description: This Open-File report is a digital geologic map database stored in a computer in the U. S. Geological Survey offices in Menlo Park, California. The study area includes the Monterey Peninsula and part of the Carmel Valley area. Geologically, this region is situated within the complexly deformed Salinian block between the active San Andreas fault to the northeast and the San Gregorio fault zone to the southwest. It also is characterized by compressional tectonics related to the San Andreas fault system and includes many poorly understood subsidiary faults (Greene and others, 1988). A series of high-angle faults trends northwestward across the quadrangles. Most of the faults in the area are discontinuous, with some less than 1 km long; however, the Tularcitos fault zone continues across the entire mapped area. These faults displace the Monterey Formation and locally offset Quaternary deposits.; abstract: This Open-File report is a digital geologic map database stored in a computer in the U. S. Geological Survey offices in Menlo Park, California. The study area includes the Monterey Peninsula and part of the Carmel Valley area. Geologically, this region is situated within the complexly deformed Salinian block between the active San Andreas fault to the northeast and the San Gregorio fault zone to the southwest. It also is characterized by compressional tectonics related to the San Andreas fault system and includes many poorly understood subsidiary faults (Greene and others, 1988). A series of high-angle faults trends northwestward across the quadrangles. Most of the faults in the area are discontinuous, with some less than 1 km long; however, the Tularcitos fault zone continues across the entire mapped area. These faults displace the Monterey Formation and locally offset Quaternary deposits.

description: This part of SIM 3319 presents the geologic and geomorphic map (see sheets 10, SIM 3319) of Offshore Refugio Beach, California. The vector data file is included in "Geology_OffshoreRefugioBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioBeach/data_catalog_OffshoreRefugioBeach.html. The offshore Refugio Beach map area largely consists of a gently offshore-dipping (<1 degree) shelf (10 to ~ 90 m) underlain by sediments derived primarily from relatively small coastal watersheds draining the Santa Ynez Mountains. Nearshore and shelf deposits are primarily sand (Qms) at depths less than about 45 m and more fine-grained sediment - very fine sand, silt and clay (Qmsf), at depths greater than about 45 m. The boundary between Qms and Qmsf is based on observations and extrapolation from sediment sampling (for example, Reid and others, 2006) and camera groundtruthing. The Qms-Qmsf boundary is transitional and approximate, expected to shift based on seasonal to annual to decadal scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits similar to Qmsf also occur below the shelfbreak on the upper slope at water depths greater than 90 m, where they are broken out as a separate unit (Qmsl) based on their location and geomorphology. More coarse-grained deposits recognized on the basis of high backscatter and in some cases moderate seafloor relief have two modes of occurrence. In the relative nearshore (10 to 30 m water depth), coarse-grained strata (Qmsc) underlie laterally coalescing and discontinuous bars at the mouths of steep coastal watersheds. Coarser-grained sediments also form several distinct lobes (Qmscl) in water depths of 25 to 70 m, about 600 to 3,000 m offshore. The lobes range in size from ~100,000 m2 to ~1.5 km2 and are mapped on the basis of high backscatter and subtle positive seafloor relief. These coarse-grained strata were clearly derived from fluvial point sources in the adjacent, steep Santa Ynez Mountains. Bedrock exposures in the nearshore west of El Capitan are assigned to the Miocene Monterey Formation based on proximity to coastal outcrops mapped by Dibblee (1981a, b). Much of the outer shelf (water depths > 70 m) is also underlain by undifferentiated Tertiary bedrock (Tbu). Based on the regional cross sections constrained by deep seismic-reflection data and borehole logs (Heck, 1998; Tennyson and Kropp, 1998; Forman and Redin, 2005; Redin, 2005) and high-resolution seismic-reflection data coupled with proprietary oil industry dartcore data (Ashley, 1977), these outer-shelf outcrops consist of the Miocene Sisquoc Formation and the Pliocene Repetto and Pico Formations. These rocks have been uplifted in a large, warped, regional south-dipping homocline that formed above the blind, north-dipping North Channel fault. The fault tip is inferred at about 1.5 sec TWT (~2 km) about 6 to 7 km offshore, beneath the slope and just outside California's State Waters. Bedrock that underlies some parts of the shelf is overlain by a thin (< 1 m?) sediment veneer, recognized based on high backscatter, flat relief, continuity with moderate to high relief bedrock outcrops, and (in some cases) high-resolution, seismic-reflection data (Qms/Qtbu. Qms/Tbu, Qms/Tm). These sediment layers are likely ephemeral - they may or may not be present based on storms, seasonal/annual patterns of sediment movement, or longer-term climate cycles. This area has a long history of petroleum production (Barnum, 1998), and grouped to solitary pockmarks (Qmp) caused by gas seeps are common features in the offshore Refugio map area. Shell discovered the Molino gas field in 1962, 4 km offshore in the southwest part of the map area. Production, by onshore directional drilling of an anticlinal trap, has been underway since the 1960's (Galloway, 1998). References cited: Ashley, R.J., Berry, R.W., and Fischer, P.J., 1977, Offshore geology and sediment distribution of the El Capitan-Gaviota continental shelf, northern Santa Barbara Channel, California: Journal of Sedimentary Petrology, v. 47, no, 1, p. 199-208. Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, p. 201€“215. Dibblee, T.W., Jr., 1981a, Geologic map of the Tajiquas Quadrangle, California: U.S. Geological Survey Open-File Report 81-371, 1:24,000. Dibblee, T.W., Jr., 1981b, Geologic map of the Gaviota Quadrangle, California: U.S. Geological Survey Open-File Report 81-374, 1:24,000. Dibblee, T.W., Jr., 1981c, Geologic map of the Santa Ynez Quadrangle, California: U.S. Geological Survey Open-File Report 81-371, 1:24,000. Dibblee, T.W., Jr., 1981d, Geologic map of the Solvang Quadrangle, California: U.S. Geological Survey Open-File Report 81-372, 1:24,000. Forman, J., and Redin, T., 2005, Santa Barbara Channel structure and correlation sections, Correlation Section no 37, Arroyo Hondo, Gaviota Quadrangle, Santa Ynez Mts. To North West Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 37, 1 sheet. Galloway, J.M., 1998, Chronology of petroleum exploration and development in the Santa Barbara channel area, offshore southern California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section and Coast Geological Society, Miscellaneous Publication 46, p. 1€“12, 1 sheet. Heck, R.G., 1998, Santa Barbara Channel Regional Formline Map, Top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., 1998, Structure and Petroleum Geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, Miscellaneous Publication 46, Plate 1. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000. Redin, T., 2005, Santa Barbara Channel structure and correlation sections, Correlation Section no 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet. Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006,usSEABED:Pacific Coast (California Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, http://pubs.usgs.gov/ds/2006/182/. Tennyson, M.E., and Kropp, A.P., 1998, Regional cross section across Santa Barbara channel from northwestern Santa Rosa Island to Canada de Molina, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., in Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section and Coast Geological Society, Miscellaneous Publication 46, 1 plate.; abstract: This part of SIM 3319 presents the geologic and geomorphic map (see sheets 10, SIM 3319) of Offshore Refugio Beach, California. The vector data file is included in "Geology_OffshoreRefugioBeach.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreRefugioBeach/data_catalog_OffshoreRefugioBeach.html. The offshore Refugio Beach map area largely consists of a gently offshore-dipping (<1 degree) shelf (10 to ~ 90 m) underlain by sediments derived primarily from relatively small coastal watersheds draining the Santa Ynez Mountains. Nearshore and shelf deposits are primarily sand (Qms) at depths less than about 45 m and more fine-grained sediment - very fine sand, silt and clay (Qmsf), at depths greater than about 45 m. The boundary between Qms and Qmsf is based on observations and extrapolation from sediment sampling (for example, Reid and others, 2006) and camera groundtruthing. The Qms-Qmsf boundary is transitional and approximate, expected to shift based on seasonal to annual to decadal scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits similar to Qmsf also occur below the shelfbreak on the upper slope at water depths greater than 90 m, where they are broken out as a separate unit (Qmsl) based on their location and geomorphology. More coarse-grained deposits recognized on the basis of high backscatter and in some cases moderate seafloor relief have two modes of occurrence. In the relative nearshore (10 to 30 m water depth), coarse-grained strata (Qmsc) underlie laterally coalescing and discontinuous bars at the mouths of steep coastal watersheds. Coarser-grained sediments also form several distinct lobes (Qmscl) in water depths of 25 to 70 m, about 600 to 3,000 m offshore. The lobes range in size from ~100,000 m2 to ~1.5 km2 and are mapped on the basis of high backscatter and subtle positive seafloor relief. These coarse-grained strata were clearly derived from fluvial point sources in the adjacent, steep Santa Ynez Mountains. Bedrock exposures in the nearshore west of El Capitan are assigned to the Miocene Monterey Formation based on proximity to coastal outcrops mapped by Dibblee (1981a, b). Much of the outer shelf (water depths > 70 m) is also underlain by undifferentiated Tertiary bedrock (Tbu). Based on the regional cross sections constrained by deep seismic-reflection data and borehole logs (Heck, 1998; Tennyson and Kropp, 1998; Forman and Redin, 2005; Redin, 2005) and high-resolution seismic-reflection data coupled with proprietary oil industry dartcore data (Ashley, 1977), these outer-shelf outcrops consist of the Miocene Sisquoc Formation and the Pliocene Repetto and Pico Formations. These rocks have been uplifted in a large, warped,

This digital map database, compiled from previously published and unpublished data, and new mapping by the authors, represents the general distribution of bedrock and surficial deposits in the mapped area. Together with the accompanying text file (skmf.txt, skmf.pdf, or skmf.ps), it provides current information on the geologic structure and stratigraphy of the area covered. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:24,000 or smaller.

This part of SIM 3261 presents data for the geologic and geomorphic map (see sheet 10, SIM 3261) of the Offshore of Carpinteria map area, California. The vector data file is included in "Geology_OffshoreCarpinteria.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCarpinteria/data_catalog_OffshoreCarpinteria.html. The offshore part of the map area largely consists of a relatively shallow (less than about 45 m deep), gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (unit Qms) at depths less than about 25 m and, at depths greater than about 25 m, are the more fine-grained sediments (very fine sand, silt, and clay) of unit Qmsf. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying (see sheet 6). It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Coarser grained deposits (coarse sand to boulders) of unit Qmsc, which are recognized on the basis of their moderate seafloor relief and high basckscatter (sheet 3), as well as camera observations (sheet 6) and sampling (Reid and others, 2006; Barnard and others, 2009), are found locally in water depths less than about 15 m, except offshore of Rincon Point where they extend to depths of about 21 m. The largest Qmsc deposits are present at the mouths of Rincon Creek and Toro Canyon Creek. The convex seafloor relief of these coarse-grained deposits suggests that they are wave-winnowed lags that armor the seafloor and are relatively resistant to erosion. The sediments may, in part, be relict, having been deposited in shallower marine (or even alluvial?) environments at lower sea levels in the latest Pleistocene and Holocene; this seems especially likely for the arcuate lobe of unit Qmsc that extends 1,700 m offshore from Rincon Point. The Qmsc deposits offshore of Toro Canyon Creek are found adjacent to onshore alluvial and alluvial fan deposits (Minor and others, 2009) and, thus, may have formed as distal-alluvial or fan-delta facies of that system. Offshore bedrock exposures are assigned to the Miocene Monterey Formation (unit Tm) and the Pliocene and Pleistocene Pico Formation (unit QTp), primarily on the basis of extrapolation from the onshore mapping of Tan and others (2003a,b), Tan and Clahan (2004), and Minor and others (2009), as well as the cross sections of Redin and others (1998, 2004) that are constrained by industry seismic-reflection data and petroleum well logs. Where uncertainty exists, bedrock is mapped as an undivided unit (QTbu). These strata are exposed in structural highs that include the Rincon Anticline and uplifts bounded by the Rincon Creek Fault and by the north and south strands of the Red Mountain Fault. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tm, Qms/QTbu, or Qms/QTp, are interpreted as ephemeral sediment layers that may or may not be continuously present, whose presence or absence is a function of the recency and intensity of storm events, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. Two offshore anthropogenic units also are present in the map area, each related to offshore hydrocarbon production. The first (unit af) consists of coarse artificial fill associated with construction of the Rincon Island petroleum-production facility near the east edge of the map area. The second (unit pd) consists of coarse artificial fill mixed with sediment and shell debris, mapped in outcrops surrounding Rincon Island and at the locations of former oil platforms "Heidi," "Hope," "Hazel," and "Hilda" from the Summerland and Carpinteria oil fields (Barnum, 1998). The Monterey Formation is the primary petroleum-source rock in the Santa Barbara channel, and the Pico Formation is one of the primary petroleum reservoirs. The Offshore of Carpinteria map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent GPS data suggest north-south shortening of about 6 to 10 mm/yr (Larson and Webb, 1992; Donnellan and others, 1993). The active, east-west-striking, north-dipping Pitas Point Fault (a broad zone that includes south-dipping reverse-fault splays), Red Mountain Fault, and Rincon Creek Fault are some of the structures on which this shortening occurs (see, for example, Jackson and Yeats, 1982; Sorlien and others, 2000). This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara Basins and represents an important earthquake hazard (see, for example, Fisher and others, 2009). References Cited: Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 201-215. Donnellan, A., Hager, B.H., and King, R.W., 1993, Discrepancy between geologic and geodetic deformation rates in the Ventura basin: Nature, v. 346, p. 333-336. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Jackson, P.A., and Yeats, R.S., 1982, Structural evolution of Carpinteria basin, western Transverse Ranges, California: American Association of Petroleum Geologists Bulletin, v. 66, p. 805-829. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet 38 p., available at http://pubs.usgs.gov/sim/3001/. Redin, T., Forman, J., and Kamerling, M.J., 1998, Regional structure section across the eastern Santa Barbara Channel, from eastern Santa Cruz Island to the Carpinteria area, Santa Ynez Mountains, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 195-200, 1 sheet. Redin, T., Kamerling, M.J., and Forman, J., 2004, Santa Barbara Channel structure and correlation sections--Correlation section no. 34R., N-S structure and correlation section, south side central Santa Ynez Mountains across the Santa Barbara channel to the east end of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 32, 1 sheet. Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED--Pacific Coast (California, Oregon, Washington) offshore surficial-sediment data release: U.S. Geological Survey Data Series 182, available at http://pubs.usgs.gov/ds/2006/182/. Sorlien, C.C., Gratier, J.P., Luyendyk, B.P., Hornafius, J.S., and Hopps, T.E., 2000, Map restoration of folded and faulted late Cenozoic strata across the Oak Ridge fault, onshore and offshore Ventura basin, California: Geological Society of America Bulletin, v. 112, p. 1,080-1,090. Tan, S.S., and Clahan, K.B., 2004, Geologic map of the White Ledge Peak 7.5' quadrangle, Santa Barbara and Ventura Counties, California--A digital database: California Geological Survey Preliminary Geologic Map, scale 1:24,000, available at http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm. Tan, S.S., Jones, T.A., and Clahan, K.B., 2003a, Geologic map of the Pitas Point 7.5' quadrangle, Ventura County, California--A digital database: California Geological Survey Preliminary Geologic Map, scale 1:24,000, available at http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm. Tan, S.S., Jones, T.A., and Clahan, K.B., 2003b, Geologic map of the Ventura 7.5' quadrangle, Ventura County, California--A digital database: California Geological Survey Preliminary Geologic Map, scale 1:24,000, available at http://www.conservation.ca.gov/cgs/rghm/rgm/preliminary_geologic_maps.htm.

This part of SIM 3281 presents data for the geologic and geomorphic map (see sheet 10, SIM 3281) of the Offshore of Santa Barbara map area, California. The vector data file is included in "Geology_OffshoreSantaBarbara.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreSantaBarbara/data_catalog_OffshoreSantaBarbara.html. The offshore part of the map area largely consists of a relatively shallow (less than 75 m deep), gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (unit Qms) at water depths less than about 35 to 50 m and, at depths greater than about 35 to 50 m, are the more fine-grained sediments (very fine sand, silt, and clay) of unit Qmsf. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying (see sheet 6). It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Coarser grained deposits (coarse sand to boulders) of unit Qmsc, which are recognized on the basis of their high backscatter and, in some cases, their moderate seafloor relief (sheets 1, 2, 3), are found most prominently in a large (about 0.75 km2) lobe that is present from about 1,800 to 3,600 m offshore of the mouth of Arroyo Burro, in water depths of about 36 to 65 m. The lobe is inferred to consist of coarse-grained sediment (coarse sand to boulders) that is resistant to erosion. Although these coarse-grained deposits almost certainly are derived from Arroyo Burro, the lobe could represent either the underflow deposits of late Holocene floods or a relict geomorphologic feature, having been deposited in shallower marine deltaic (or even alluvial?) environments at lower sea levels in the latest Pleistocene and early Holocene. Unit Qmsc also is present in shallower water (depths of about 10 to 20 m), most notably in a small area (approximately 0.09 km2) that extends offshore from Montecito Creek, in the eastern part of the map area. The presence of coarser grained sediment (coarse sand and possibly gravel) also is inferred in shallower water (depths of 10 to 20 m) offshore from Arroyo Burro, but these deposits are mapped as unit Qmss because they are found within arcuate scour depressions that have been referred to as "rippled scour depressions" (see, for example, Cacchione and others, 1984; Phillips, 2007) or "sorted bedforms" (see, for example, Murray and Thieler, 2004; Goff and others, 2005; Trembanis and Hume, 2011). Although the general area in which Qmss scour depressions are found is not likely to change substantially, the boundaries of the unit(s), as well as the locations of individual depressions and their intervening flat sand sheets, likely are ephemeral, changing during significant storm events. Hydrocarbon-seep-induced topography, which is present most prominently along the axis of anticlines, includes many features (described by Keller and others, 2007) along the trend of the Mid-Channel Anticline, about 10 km south of the map area in the Santa Barbara Channel. Geologic map units associated with hydrocarbon emissions in the map area include grouped to solitary pockmarks (unit Qmp) and asphalt (tar) deposits (unit Qas), as well as areas of undifferentiated hydrocarbon-related features (unit Qhfu) that probably include a mix of mounds, mud volcanoes, pockmarks, carbonate mats, and other constructional and erosional "seabed forms" (see Keller and others, 2007), all of which are superimposed on consolidated, undivided Miocene and Pliocene bedrock (unit Tbu). Offshore bedrock exposures are assigned to the Miocene Monterey Formation (unit Tm) and to the undivided Miocene and Pliocene bedrock unit (Tbu), primarily on the basis of extrapolation from the onland geologic mapping of Minor and others (2009), as well as the geologic cross sections of Redin (2005). These cross sections, which are constrained by industry seismic-reflection data and petroleum well logs, suggest that a considerable part of the undivided bedrock unit may belong to the Pliocene and Pleistocene Pico Formation. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tbu or Qms/Tm, are interpreted as ephemeral sediment layers that may or may not be continuously present, depending on storms, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. The Santa Barbara Channel region, including the map area, has a long history of petroleum production (Barnum, 1998). The Monterey Formation is the primary petroleum-source rock in the Santa Barbara Channel, and the Pico Formation is one of the primary petroleum reservoirs. The bedrock units typically are exposed in structural highs that include uplifts associated with the partly blind(?), south-dipping Rincon Creek Fault Zone and the outer shelf anticlinal uplift that developed above the south strand of the Red Mountain Fault in the southwestern part of the map area. The Offshore of Santa Barbara map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent GPS data suggest north-south shortening of about 6 mm/yr (Larson and Webb, 1992). The active, east-west-striking Red Mountain and Rincon Creek Faults and their related folds are some of the structures on which this shortening occurs. This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara Basins and represents an important earthquake hazard (see, for example, Fisher and others, 2009). Very high uplift rates of onland marine terraces from More Mesa (2.2 mm/yr), in the western part of the map area, to Summerland (0.7 mm/yr), a few kilometers east of the map area, are further indication of rapid shortening in this region (Keller and Gurrola, 2000). References Cited: Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 201-215. Cacchione, D.A., Drake, D.E., Grant, W.D., and Tate, G.B., 1984, Rippled scour depressions of the inner continental shelf off central California: Journal of Sedimentary Petrology, v. 54, p. 1,280-1,291. Dibblee, T.W., Jr., 1986a, Geologic map of the Carpinteria quadrangle, Santa Barbara County, California: Santa Barbara, Calif., Dibblee Geological Foundation Map DF-04, scale 1:24,000. Dibblee, T.W., Jr., 1986b, Geologic map of the Santa Barbara quadrangle, Santa Barbara County, California: Santa Barbara, Calif., Dibblee Geological Foundation Map DF-06, scale 1:24,000. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Goff, J.A., Mayer, L.A., Traykovski, P., Buynevich, I., Wilkens, R., Raymond, R., Glang, G., Evans, R.L., Olson, H., and Jenkins, C., 2005, Detailed investigations of sorted bedforms or "rippled scour depressions," within the Martha's Vineyard Coastal Observatory, Massachusetts: Continental Shelf Research, v. 25, p. 461-484. Keller, E.A., Duffy, M., Kennett, J.P., and Hill, T., 2007, Tectonic geomorphology and hydrocarbon potential of the Mid-Channel anticline, Santa Barbara Basin, California: Geomorphology, v. 89, p. 274-286. Keller, E.A., and Gurrola, L.D., 2000, Final report, July, 2000--Earthquake hazard of the Santa Barbara fold belt, California: NEHRP Award #99HQGR0081, SCEC Award #572726, 78 p., available at http://www.scec.org/research/98research/98gurrolakeller.pdf. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale 1:25,000, 1 sheet, pamphlet 38 p., available at http://pubs.usgs.gov/sim/3001/. Murray, B., and Thieler, E.R., 2004, A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and "rippled scour depressions": Continental Shelf Research, v. 24, no. 3, p. 295-315. Phillips, E., 2007, Exploring rippled scour depressions offshore Huntington Beach, CA: Santa Cruz, University of California, M.S. thesis, 58 p. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 34A, Summerland area, Santa Ynez Mountains, across the east central Santa Barbara Channel to the China Bay area, Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 34A, 1 sheet. Reid, J.A., Reid, J.M., Jenkins, C.J., Zimmerman, M., Williams, S.J., and Field, M.E., 2006, usSEABED--Pacific Coast (California, Oregon, Washington) offshore

description: This part of SIM 3302 presents data for folds for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Folds_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. This map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). Significant clockwise rotation--at least 90 degrees--since the Miocene has been proposed for the Western Transverse Ranges province (Luyendyk and others, 1980; Hornafius and others, 1986; Nicholson and others, 1994), and this region is presently undergoing north-south shortening (see, for example, Larson and Webb, 1992). In the eastern part of the map area, cross sections suggest that this shortening is, in part, accommodated by offset on the North Channel, Red Mountain, South Ellwood, and More Creek Fault systems (Bartlett, 1998; Heck, 1998; Redin and others, 2005; Leifer and others, 2010). Crustal deformation in the western part of the Offshore of Coal Oil Point map area apparently is less complex than that in the eastern part (Redin, 2005); the western structure is dominated by a large, south-dipping homocline that extends from the south flank of the Santa Ynez Mountains beneath the continental shelf. References Cited: Bartlett, W.L., 1998, Ellwood oil field, Santa Barbara County, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 217-237. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Heck, R.G., 1998, Santa Barbara Channel regional formline map, top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 1 plate. Hornafius, J.S., Luyendyk, B.P., Terres, R.R., and Kamerling, M.J., 1986, Timing and extent of Neogene rotation in the western Transverse Ranges, California: Geological Society of America Bulletin, v. 97, p. 1,476-1,487. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Leifer, I., Kamerling, M., Luyendyk, B.P., and Wilson, D.S., 2010, Geologic control of natural marine hydrocarbon seep emissions, Coal Oil Point seep field, California: Geo-Marine Letters, v. 30, p. 331-338, doi:10.1007/s00367-010-0188-9. Luyendyk, B.P., Kamerling, M.J., and Terres, R.R., 1980, Geometric model for Neogene crustal rotations in southern California: Geological Society of America Bulletin, v. 91, p. 211-217. Nicholson, C., Sorlien, C., Atwater, T., Crowell, J.C., and Luyendyk, B.P., 1994, Microplate capture, rotation of the western Transverse Ranges, and initiation of the San Andreas transform as a low-angle fault system: Geology, v. 22, p. 491-495. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara Channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 1 sheet. Redin, T., Kamerling, M., and Forman, J., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 35, North Ellwood-Coal Oil Point area across the Santa Barbara Channel to the north coast of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet.; abstract: This part of SIM 3302 presents data for folds for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Folds_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. This map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). Significant clockwise rotation--at least 90 degrees--since the Miocene has been proposed for the Western Transverse Ranges province (Luyendyk and others, 1980; Hornafius and others, 1986; Nicholson and others, 1994), and this region is presently undergoing north-south shortening (see, for example, Larson and Webb, 1992). In the eastern part of the map area, cross sections suggest that this shortening is, in part, accommodated by offset on the North Channel, Red Mountain, South Ellwood, and More Creek Fault systems (Bartlett, 1998; Heck, 1998; Redin and others, 2005; Leifer and others, 2010). Crustal deformation in the western part of the Offshore of Coal Oil Point map area apparently is less complex than that in the eastern part (Redin, 2005); the western structure is dominated by a large, south-dipping homocline that extends from the south flank of the Santa Ynez Mountains beneath the continental shelf. References Cited: Bartlett, W.L., 1998, Ellwood oil field, Santa Barbara County, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 217-237. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Heck, R.G., 1998, Santa Barbara Channel regional formline map, top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 1 plate. Hornafius, J.S., Luyendyk, B.P., Terres, R.R., and Kamerling, M.J., 1986, Timing and extent of Neogene rotation in the western Transverse Ranges, California: Geological Society of America Bulletin, v. 97, p. 1,476-1,487. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Leifer, I., Kamerling, M., Luyendyk, B.P., and Wilson, D.S., 2010, Geologic control of natural marine hydrocarbon seep emissions, Coal Oil Point seep field, California: Geo-Marine Letters, v. 30, p. 331-338, doi:10.1007/s00367-010-0188-9. Luyendyk, B.P., Kamerling, M.J., and Terres, R.R., 1980, Geometric model for Neogene crustal rotations in southern California: Geological Society of America Bulletin, v. 91, p. 211-217. Nicholson, C., Sorlien, C., Atwater, T., Crowell, J.C., and Luyendyk, B.P., 1994, Microplate capture, rotation of the western Transverse Ranges, and initiation of the San Andreas transform as a low-angle fault system: Geology, v. 22, p. 491-495. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara Channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 1 sheet. Redin, T., Kamerling, M., and Forman, J., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 35, North Ellwood-Coal Oil Point area across the Santa Barbara Channel to the north coast of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet.

This part of DS 781 presents data for the geologic and geomorphic map of Monterey Canyon and Vicinity, California. The vector data file is included in "Geology_MontereyCanyon.zip," which is accessible from http://dx.doi.org/10.5066/F7XD0ZQ4. The offshore part of the Monterey Canyon and Vicinity map area contains two geomorphic regionsâ (1) the continental shelf, and (2) Monterey Canyon and its tributaries (the Monterey Canyon "system"), including Soquel Canyon. The continental shelf in the Monterey Canyon and Vicinity map area is relatively flat and characterized by a variably thick (and locally absent) cover of uppermost Pleistocene and Holocene sediment that overlies Neogene bedrock and Pleistocene paleo-channel and canyon fill (unit Qcf). Inner-shelf and nearshore deposits are mostly sand (unit Qms), and are thickest (as much as 32 m) in a shore-parallel bar offshore that extends to the mouth of the Salinas River (sheet 9). Slope failures off of the west flank of this delta-mouth bar have resulted in three west-trending elongate sandy lobes (unit Qmsl); individual lobes are as much as 3,000-m long and 800-m wide, have as much as 150 cm of relief above the surrounding smooth seafloor, and are commonly transitional to upslope chutes. Unit Qmsf lies offshore of unit Qms in the mid shelf, consists primarily of mud and muddy sand, and is commonly extensively bioturbated. Sediment cover typically thins in the offshore direction and toward Monterey Canyon (sheet 9); Pleistocene paleo-channel and canyon fill (unit Qcf) and the upper Miocene and Pliocene Purisima Formation (unit Tp; Powell and others, 2007) are exposed on the outer shelf and along the rims of the modern Monterey Canyon system. Both the Purisima Formation (Tp) and Pleistocene paleo-channel and canyon fill (Qcf) are in places overlain by a thin (less than 1 m?) veneer of sediment recognized on the basis of high backscatter, flat relief, continuity with moderate- to higher-relief outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tp or Qms/Qcf, are interpreted as ephemeral sediment layers that may or may not be continuously present, depending on storms, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. Sea level has risen about 125 to 130 meters over about the last 21,000 years (for example, Stanford and others, 2011), leading to broadening of the continental shelf, progressive eastward migration of the shoreline, and associated transgressive erosion and deposition. Sea-level rise was apparently not steady, leading to development of pairs of shoreline angles and adjacent submerged wave-cut platforms (Kern, 1977) during pulses of relative stability. Latest Pleistocene paleoshorelines are best preserved along the flanks of Soquel Canyon, where three sets of wave cut platforms (units Qwp1, Qwp2, Qwp3) and paired risers (units Qwpr1, Qwpr2, Qwpr3) are bounded by shoreline angles at water depths of about 120 to 125 meters, about 108 meters, and about 96 to 100 meters. Within the Monterey Canyon system, geologic and geomorphic units are delineated and characterized on the basis of multibeam bathymetry (sheet 1), backscatter (sheet 3), published samples and descriptions of geology within the canyon system (e.g., Greene, 1977; Barry and others, 1996; Stakes and others, 1999; Wagner and others, 2002; Paull and others, 2005a, 2005b, 2010), and, where available, seismic-reflection profiles (sheet 8) and video observations (sheet 6). Major geologic and geomorphic components within the canyons include the canyon-head region, canyon axial channels, canyon walls, and canyon benches and platforms. The canyon-head region of Monterey Canyon includes sandy channel fill (unit Qchc; Paull and others, 2005a) and inter-channel sediment-draped ridges (unit Qchr) inferred to have formed largely by erosion of the canyon head into older canyon and (or) channel fill. There is a geomorphic gradational transition down-canyon from canyon-head channel fill (unit Qchc) to proximal active axial channel fill (unit Qcpcf), and both channel-fill units include dynamic crescent-shaped sandy bedforms (Paull and others, 2005a, 2010; Smith and others, 2005; Xu and others, 2008). Beyond the canyon head region, the axial channel of Monterey Canyon forms a sinuous ribbon of coarse-grained deposits (unit Qccf3), sloping about 3.5° to the western edge of the map area (Paull and others, 2005a, 2010; Greene and others, 2002; Xu and others, 2008). Xu and others (2002, 2008, 2013) and Paull and others (2010) have documented recent sediment-gravity flows down the Monterey Canyon axial channel, indicating that it is an active conduit of sediment transport. Map units adjacent to the axial channel include canyon walls, benches, and landslides. Canyon walls (unit Qmscw) that are relatively smooth are generally covered by muddy Quaternary sediments (Paull and others, 2005a, 2010), whereas steeper and rougher segments of canyon walls commonly contain exposures of bedrock or incised Pleistocene paleo-channel and canyon fill (unit Qcfcw). Purisima Formation outcrops occur in the upper canyon walls (unit Tpcw). Older, underlying bedrock units (Greene, 1977; Barry and others, 1996; Stakes and others, 1999; Wagner and others, 2002) are exposed at greater depths along canyon walls. These older units include the Miocene Monterey Formation (unit Tmcw), Miocene and Oligocene sandstone (unit Tscw), Tertiary volcanics intrusive into sedimentary bedrock and Cretaceous granodiorite (unit Tvcw), and Cretaceous granodiorite (unit Kgcw). Exposures of these bedrock units and incised Pleistocene paleo-channel and canyon fill outcrops in the canyon walls (unit Qcfcw) are inferred to result from a combination of erosion by dense sediment flows down the axial channel and continuing landslide failure of the canyon walls. Relatively flat areas immediately adjacent to the axial channel or within the canyon walls are mapped as inner benches (unit Qcb2) and outer benches (unit Qcb1), respectively (bench term from Paull and others, 2010 and Maier and others, 2012). Benches generally have lower slopes than surrounding canyon walls and accumulate fine-grained sediments, including muddy marine, hemipelagic, turbidite, and landslide deposits (Paull and others, 2005a, 2010). Relatively flat, smooth, sediment-covered platforms on the crests of bathymetric divides between canyon meanders are mapped as canyon platforms (unit Qmscp). Regions of the canyon walls characterized by steep, scallop-shaped scarps and paired hummocky mounds are mapped as landslides (units Qlsm). Multiple generations of landslides are mapped (units Qlsm1, Qlsm2, Qlsm3) where failure of older landslides yielded younger landslides. Paull and others (2005b) noted that landslide scarps are commonly associated with chemosynthetic biologic communities. Landslide blocks in the Monterey Canyon system (Qlsmb) are distinguished by positive relief and deflection of an axial channel. Landslide blocks are inferred to be bedrock, similar to bedrock found in adjacent canyon walls. One block in the distal portion of the Monterey Canyon system in the map area (Qlsmb1) has been previously studied, identified as composed of Cretaceous granodiorite, and informally named the â Navy Slumpâ (Greene and others, 2002; Paull et al., 2005a). Soquel Canyon is the most prominent of five mapped tributaries to Monterey Canyon. During the sea-level lowstand about 21,000 years ago, Soquel Creek fed directly into Soquel Canyon, carrying coarse-grained sediment directly to the Monterey Canyon system (see sheet 9). Sea-level rise isolated Soquel Canyon from its paired coastal watershed, and this "abandoned" tributary canyon is now being filled largely with Holocene hemipelagic sediment. The Soquel Canyon axial channel is divided into two sections based on lithology of the fill deposits. The abandoned submarine canyon axial channel fill (unit Qccf2) in upper Soquel canyon consists of fine-grained sediment. In lower Soquel Canyon adjacent to Monterey Canyon, the abandoned submarine canyon axial channel fill (unit Qccf1) contains gravel, sand, and mud (Stakes and others, 1999) that is possibly derived from Holocene and Pleistocene landslides, and may also contain bedrock exposures. Two other abandoned canyon tributaries (unit Qctf1) were likely connected to the Pajaro River during the sea-level lowstand. These two tributaries are mapped east of Soquel Canyon on the north flank of Monterey Canyon. One abandoned tributary (unit Qctf2) is mapped on the south flank of Monterey Canyon and appears to have been connected to the Salinas River during the sea-level lowstand. The shelf north and south of Monterey Canyon in the Monterey Canyon and Vicinity map area is cut by a diffuse zone of northwest striking, steeply dipping to vertical faults comprising the Monterey Bay Fault Zone (MBFZ). This zone, originally mapped by Greene (1977, 1990), extends about 45 km across outer Monterey Bay (Map E on sheet 9). Fault strands within the MBFZ are mapped with high-resolution seismic-reflection profiles (sheet 8). Seismic-reflection profiles traversing this diffuse zone cross as many as 9 faults over a width of about 8 km (see, for example, fig. 7 on sheet 8). The zone lacks a continuous "master fault," along which deformation is concentrated. Fault length ranges up to about 20 km (based on mapping outside this map area), but most strands are only about 2- to 7-km long. Faults in this diffuse zone cut through Neogene bedrock and locally appear to minimally disrupt overlying inferred Quaternary sediments. The presence of warped reflections along some fault strands suggests that fault offsets may be both vertical and strike-slip. Mapping fault strands in the MBFZ across the Monterey Canyon system is problematic. The combination of steep relief, increased water depths, and massive to poorly-stratified

description: This part of SIM 3302 presents data for faults for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Faults_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. This map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). Significant clockwise rotation--at least 90 degrees--since the early Miocene has been proposed for the Western Transverse Ranges province (Luyendyk and others, 1980; Hornafius and others, 1986; Nicholson and others, 1994), and this region is presently undergoing north-south shortening (see, for example, Larson and Webb, 1992). In the eastern part of the map area, cross sections suggest that this shortening is, in part, accommodated by offset on the North Channel, Red Mountain, South Ellwood, and More Creek Fault systems (Bartlett, 1998; Heck, 1998; Redin and others, 2005; Leifer and others, 2010). Crustal deformation in the western part of the Offshore of Coal Oil Point map area apparently is less complex than that in the eastern part (Redin, 2005); the western structure is dominated by a large, south-dipping homocline that extends from the south flank of the Santa Ynez Mountains beneath the continental shelf. References Cited: Bartlett, W.L., 1998, Ellwood oil field, Santa Barbara County, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 217-237. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Heck, R.G., 1998, Santa Barbara Channel regional formline map, top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 1 plate. Hornafius, J.S., Luyendyk, B.P., Terres, R.R., and Kamerling, M.J., 1986, Timing and extent of Neogene rotation in the western Transverse Ranges, California: Geological Society of America Bulletin, v. 97, p. 1,476-1,487. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Leifer, I., Kamerling, M., Luyendyk, B.P., and Wilson, D.S., 2010, Geologic control of natural marine hydrocarbon seep emissions, Coal Oil Point seep field, California: Geo-Marine Letters, v. 30, p. 331-338, doi:10.1007/s00367-010-0188-9. Luyendyk, B.P., Kamerling, M.J., and Terres, R.R., 1980, Geometric model for Neogene crustal rotations in southern California: Geological Society of America Bulletin, v. 91, p. 211-217. Nicholson, C., Sorlien, C., Atwater, T., Crowell, J.C., and Luyendyk, B.P., 1994, Microplate capture, rotation of the western Transverse Ranges, and initiation of the San Andreas transform as a low-angle fault system: Geology, v. 22, p. 491-495. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara Channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 1 sheet. Redin, T., Kamerling, M., and Forman, J., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 35, North Ellwood-Coal Oil Point area across the Santa Barbara Channel to the north coast of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet.; abstract: This part of SIM 3302 presents data for faults for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Faults_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. This map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). Significant clockwise rotation--at least 90 degrees--since the early Miocene has been proposed for the Western Transverse Ranges province (Luyendyk and others, 1980; Hornafius and others, 1986; Nicholson and others, 1994), and this region is presently undergoing north-south shortening (see, for example, Larson and Webb, 1992). In the eastern part of the map area, cross sections suggest that this shortening is, in part, accommodated by offset on the North Channel, Red Mountain, South Ellwood, and More Creek Fault systems (Bartlett, 1998; Heck, 1998; Redin and others, 2005; Leifer and others, 2010). Crustal deformation in the western part of the Offshore of Coal Oil Point map area apparently is less complex than that in the eastern part (Redin, 2005); the western structure is dominated by a large, south-dipping homocline that extends from the south flank of the Santa Ynez Mountains beneath the continental shelf. References Cited: Bartlett, W.L., 1998, Ellwood oil field, Santa Barbara County, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 217-237. Fisher, M.A., Sorlien, C.C., and Sliter, R.W., 2009, Potential earthquake faults offshore southern California from the eastern Santa Barbara channel to Dana Point, in Lee, H.J., and Normark, W.R., eds., Earth science in the urban ocean--The Southern California Continental Borderland: Geological Society of America Special Paper 454, p. 271-290. Heck, R.G., 1998, Santa Barbara Channel regional formline map, top Monterey Formation, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 1 plate. Hornafius, J.S., Luyendyk, B.P., Terres, R.R., and Kamerling, M.J., 1986, Timing and extent of Neogene rotation in the western Transverse Ranges, California: Geological Society of America Bulletin, v. 97, p. 1,476-1,487. Larson, K.M., and Webb, F.H., 1992, Deformation in the Santa Barbara Channel from GPS measurements 1987-1991: Geophysical News Letters, v. 19, p. 1,491-1,494. Leifer, I., Kamerling, M., Luyendyk, B.P., and Wilson, D.S., 2010, Geologic control of natural marine hydrocarbon seep emissions, Coal Oil Point seep field, California: Geo-Marine Letters, v. 30, p. 331-338, doi:10.1007/s00367-010-0188-9. Luyendyk, B.P., Kamerling, M.J., and Terres, R.R., 1980, Geometric model for Neogene crustal rotations in southern California: Geological Society of America Bulletin, v. 91, p. 211-217. Nicholson, C., Sorlien, C., Atwater, T., Crowell, J.C., and Luyendyk, B.P., 1994, Microplate capture, rotation of the western Transverse Ranges, and initiation of the San Andreas transform as a low-angle fault system: Geology, v. 22, p. 491-495. Redin, T., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 36, N-S structure and correlation section, western Santa Ynez Mountains across the Santa Barbara Channel to Santa Rosa Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 36, 1 sheet. Redin, T., Kamerling, M., and Forman, J., 2005, Santa Barbara Channel structure and correlation sections--Correlation Section no. 35, North Ellwood-Coal Oil Point area across the Santa Barbara Channel to the north coast of Santa Cruz Island: American Association of Petroleum Geologists, Pacific Section, Publication CS 35, 1 sheet.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Monterey map area, California. The vector data file is included in "Geology_OffshoreMonterey.zip," which is accessible from http://dx.doi.org/10.3133/ofr20161110. The offshore part of the Offshore of Monterey map area contains two geomorphic regions—(1) the continental shelf, and (2) Carmel Canyon and its tributaries (part of the “Offshore Monterey system†of Greene and others (2002)). The relatively flat continental shelf in the Offshore of Monterey map area consists of exposed bedrock or bedrock overlain by only a thin (< 5 m) cover of sediment). The thickest sediment in the map area (about 16 m) occurs in a broad depression about 2 km north of the north tip of the Monterey Peninsula at water depths of about 75 to 85 m (sheet 9, Map B). Inner- to mid-shelf and nearshore deposits are mostly sand (unit Qms), with coarse sand and gravel (unit Qmsc) present in the mid-shelf about 2 km offshore of Seaside. Unit Qmsf lies offshore of unit Qms in the mid to outer shelf (water depths of 65 to 150 m), consists primarily of mud and muddy sand, and is commonly extensively bioturbated. Unit Qmsd typically is mapped as erosional lags in scour depressions that are bounded by relatively sharp or, less commonly, diffuse contacts with the horizontal sand sheets of unit Qms. These depressions typically are irregular to lenticular and a few tens of centimeters deep, and they range in size from a few tens of square meters to as much as 2,400,000 m2. They most commonly are found at water depths that range from about 15 to 90 m. Such scour depressions are common along this stretch of the California coast (see, for example, Cacchione and others, 1984; Hallenbeck and others, 2012; Davis and others, 2013), where offshore sandy sediment can be relatively thin (and, thus, is unable to fill the depressions) owing to low sediment supply from rivers and also to significant erosion and offshore transport of sediment during large northwest winter swells. Such features have been referred to as “rippled scour depressions†(see, for example, Cacchione and others, 1984) or “sorted bedforms†(see, for example, Goff and others, 2005; Trembanis and Hume, 2011). Although the general areas in which both unit Qmsd scour depressions and surrounding Qms sand sheets are found are not likely to change substantially, the boundaries of the unit(s) likely are ephemeral, changing seasonally and during significant storm events. Sea level has risen about 125 to 130 m over about the last 21,000 years (for example, Stanford and others, 2011), leading to broadening of the continental shelf, progressive eastward migration of the shoreline, and associated transgressive erosion and deposition. A submerged shoreline along the flank of Carmel Canyon (water depths of 80 to 90 m) represents a relative sea-level stillstand, indicating that sea-level rise was not steady. Associated map units include a wave-cut platform (unit Qwp) and an adjacent riser (unit Qwpr). Bedrock units forming seafloor outcrops on the shelf include Cretaceous granitic rocks (unit Kgr), the Paleocene Carmelo Formation (unit Tc; Bowen, 1965), Oligocene volcanic rocks (basaltic andesite, unit Tvb), the Miocene Monterey Formation (unit Tm), the upper Miocene and Pliocene Purisima Formation (unit Tp) (Eittreim and others, 2002; Wagner and others, 2002). Unit Tu is mapped where rocks of the Carmelo, Monterey, and Purisima Formations cannot be confidently divided. Unit Kgr is notably characterized by high backscatter (sheet 3) and rough, massive, and fractured seafloor texture. In contrast the less indurated Neogene sedimentary rocks, most notably units Tm and Tp, form lower relief outcrops with common “ribbed†morphology reflecting the differential hardness (and hence erodibility) of sedimentary layers. Several of these bedrock units are in places overlain by a thin (less than 1 m?) veneer of sediment recognized on the basis of high backscatter, flat relief, continuity with moderate- to higher-relief outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units (for example, Qms/Kgr or Qms/Tp) are interpreted as ephemeral sediment layers that may or may not be continuously present, depending on storms, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. The shelf north and east of the Monterey Bay Peninsula in the Offshore of Monterey map area is cut by a diffuse zone of northwest striking, steeply dipping to vertical faults comprising the Monterey Bay Fault Zone (MBFZ). This zone, originally mapped by Greene (1977, 1990), extends about 45 km across Monterey Bay (Map E on sheet 9). Fault strands within the MBFZ are mapped with high-resolution seismic-reflection profiles (sheet 8). Seism... Visit https://dataone.org/datasets/48147f19-f48b-446f-88ee-d357aa0e851c for complete metadata about this dataset.

This part of DS 781 presents data for the geologic and geomorphic map of the Drakes Bay and Vicinity map area, California. The polygon shapefile is included in "Geology_DrakesBay.zip," which is accessible from http://pubs.usgs.gov/ds/781/DrakesBay/data_catalog_DrakesBay.html. Marine geology and geomorphology was mapped in the Drakes Bay and Vicinity map area from approximate Mean High Water (MHW) to the 3-nautical-mile limit of Californiaâ  s State Waters. MHW is defined at an elevation of 1.46 m above the North American Vertical Datum of 1988 (NAVD 88) (Weber and others, 2005). Offshore geologic units were delineated on the basis of integrated analyses of adjacent onshore geology with multibeam bathymetry and backscatter imagery, seafloor-sediment and rock samples (Reid and others, 2006), digital camera and video imagery, and high-resolution seismic-reflection profiles. The onshore bedrock mapping was compiled from Galloway (1977), Clark and Brabb (1997), and Wagner and Gutierrez (2010). Quaternary mapping was compiled from Witter and others (2006) and Wagner and Gutierrez (2010), with unit contacts modified based on analysis of 2012 LiDAR imagery; and additional Quaternary mapping by M.W. Manson. San Andreas Fault traces are compiled from California Geological Survey (1974) and Wagner and Gutierrez (2010). The offshore part of the map area includes the large embayment known as Drakes Bay and extends from the shoreline to water depths of about 40 to 60 m. The continental shelf is quite wide in this area, with the shelfbreak located west of the Farallon High, about 35 km offshore. This map area is largely characterized by a relatively flat (<0.8à °) bedrock platform that is locally overlain by thin sediment cover. Sea level has risen about 125 to 130 m over about the last 21,000 years (for example, Lambeck and Chappell, 2001; Peltier and Fairbanks, 2006), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and associated transgressive erosion and deposition (for example, Catuneanu, 2006). Land-derived sediment was carried into this dynamic setting, and then subjected to full Pacific Ocean wave energy and strong currents before deposition or offshore transport. Tectonic influences impacting shelf morphology and geology are related to local faulting, folding, uplift, and subsidence. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse fault zone (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone that is associated with two main fault structures, the Point Reyes Fault and the Western Point Reyes Fault. Late Pleistocene uplift of marine terraces on the Point Reyes Peninsula suggests active deformation west of the San Andreas Fault (Grove and others, 2010). Offshore Double Point, the Point Reyes Fault is associated with warping and folding of Neogene strata visible on high-resolution seismic data. In this map area the cumulative (post-Miocene) slip-rate on the Point Reyes Fault Zone is poorly constrained, but is estimated to be 0.3 mm/yr based on vertical offset of granitic basement rocks (McCulloch, 1987; Wills and others, 2008). Salinian granitic basement rocks (unit Kgg) are exposed on the Point Reyes headland and offshore in the northwest corner of the map area. The granitic rocks are mapped on the basis of massive, bulbous texture and extensive fracturing in multibeam imagery, and high backscatter. Much of the inner shelf is underlain by Neogene marine sedimentary rocks that form the core of the Point Reyes syncline (Weaver, 1949), and include the mid- to late Miocene Monterey Formation (unit Tm), late Miocene Santa Margarita Formation (unit Tsm), late Miocene Santa Cruz Mudstone (unit Tsc), and late Miocene to early Pliocene Purisima Formation (unit Tp; Clark and Brabb, 1997; Powell and others, 2007). At Millers Point, the Monterey Formation is exposed onshore and on the seafloor in the nearshore and appears highly fractured with bedding planes difficult to identify. Seafloor exposures of the younger Tsc and Tp units are characterized by distinct rhythmic bedding and are often gently folded and fractured. Unit Tu refers to seafloor outcrops that may include unit Tm, unit Tsm, or unit Tsc. The Santa Cruz Mudstone and underlying Santa Margarita Sandstone at Double Point are more than 450 m thick in an oil test well (Clark and Brabb, 1997), and these units form coastal bluffs and tidal zone exposures that extend onto the adjacent bedrock shelf. The Santa Cruz Mudstone thins markedly to the northwest and disappears from the section about 10 km to the northwest where Purisima Formation unconformably overlies Santa Margarita Sandstone. We infer the offshore contact between the Santa Cruz Mudstone and Purisima Formation based on an angular unconformity visible in seismic data just southeast of the map area. This angular unconformity becomes conformable to the northwest in the Drakes Bay and Vicinity map area. We suggest this contact bends northward in the subsurface and comes onshore near U-Ranch (Galloway, 1977; Clark and Brabb, 1997). Given the lack of lithological evidence for this contact offshore Double Point, this interpretation is speculative, and an alternative interpretation is that the noted unconformity occurs within the Santa Cruz Mudstone. For this reason, we have queried unit Tp here to indicate this uncertainty. Modern nearshore sediments are mostly sand (unit Qms) and a mix of sand, gravel, and cobbles (units Qmsc and Qmsd). The more coarse-grained sands and gravels (units Qmsc and Qmsd) are primarily recognized on the basis of bathymetry and high backscatter (see Bathymetry--Drakes Bay, California and Backscattter A to C--Drakes Bay, California, DS 781, for more information). Both Qmsc and Qmsd typically have abrupt landward contacts with bedrock and form irregular to lenticular exposures that are commonly elongate in the shore-normal direction. Contacts between units Qmsc and Qms are typically gradational. Unit Qmsd forms erosional lags in scoured depressions that are bounded by relatively sharp and less commonly diffuse contacts with unit Qms horizontal sand sheets. These depressions are typically a few tens of centimeters deep and range in size from a few 10's of meters to more than 1 km2. There are two areas of high-backscatter, and rough seafloor that are notable in that each includes several small (less than about 20,000 m2), irregular "lumps", with as much as 1 m of positive relief above the seafloor (unit Qsr). Southeast of the Point Reyes headland, unit Qsr occurs in water depths between 50 and 60 meters, with individual lumps randomly distributed to west-trending. Southwest of Double Point, unit Qsr occurs in water depths between 30 and 40 meters, with individual lumps having a more northwest trend. Seismic-reflection data (see field activity S-8-09-NC) reveal this lumpy material rests on several meters of latest Pleistocene to Holocene sediment and is thus not bedrock outcrop. Rather, it seems likely that this lumpy material is marine debris, possibly derived from one (or more) of the more than 60 shipwrecks offshore of the Point Reyes Peninsula between 1849 and 1940 (National Park Service, 2012). It is also conceivable that this lumpy terrane consists of biological "hardgrounds". Video transect data crossing unit Qsr near the Point Reyes headland was of insufficient quality to distinguish between these above alternatives. A transition to more fine-grained marine sediments (unit Qmsf) occurs around 50-60 m depth south of the Point Reyes headland and west of Double Point, however, directly south and east of Drakes Estero estuary, backscatter and seafloor sediment samples (Chin and others, 1997) suggest fine-grained sediments extend into water depths as shallow as 30 m. Unit Qmsf is commonly extensively bioturbated and consists primarily of mud and muddy sand. These fine-grained sediments are inferred to have been derived from the Drakes and Limantour Esteros or from the San Francisco Bay to the south, via predominantly northwest flow at the seafloor (Noble and Gelfenbaum, 1990). References Cited Catuneanu, O., 2006, Principles of Sequence Stratigraphy: Amsterdam, Elsevier, 375 p. Chin, J.L., Karl, H.A., and Maher, N.M., 1997, Shallow subsurface geology of the continental shelf, Gulf of the Farallones, California, and its relationship to surficial seafloor characteristics: Marine Geology, v. 137, p. 251-269. Clark, J.C., and Brabb, E.E., 1997, Geology of the Point Reyes National Seashore and vicinity: U.S. Geological Survey Open-File Report 97-456, scale 1:48,000. Grove, K., Sklar, L.S., Scherer, A.M., Lee, G., and Davis, J., 2010, Accelerating and spatially-varying crustal uplift and its geomorphic expression, San Andreas Fault zone north of San Francisco, California: Tectonophysics, v. 495, p. 256-268. Hoskins E.G., Griffiths, J.R., 1971, Hydrocarbon potential of northern and central California offshore: American Association of Petroleum Geologists Memoir 15, p. 212-228. Lambeck, K., and Chappell, J., 2001, Sea level change through the last glacial cycle: Science, v. 292, p. 679-686, doi: 10.1126/science.1059549. McCulloch, D.S., 1987, Regional geology and hydrocarbon potential of offshore Central California, in Scholl, D.W., Grantz, A., and Vedder, J.G., eds., Geology and resource potential of the continental margin of Western North America and adjacent ocean basins-Beaufort Sea to Baja California: Circum-Pacific Council for Energy and Mineral Resources Earth Science Series, v. 6, p. 353-401. National Park Service, 2012, Shipwrecks at Point Reyes, available at:

This polygon shapefile depicts geological features within the offshore area of Santa Barbara, California. The offshore part of the map area largely consists of a relatively shallow (less than 75 m deep), gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (unit Qms) at water depths less than about 35 to 50 m and, at depths greater than about 35 to 50 m, are the more fine-grained sediments (very fine sand, silt, and clay) of unit Qmsf. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying (see sheet 6). It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Coarser grained deposits (coarse sand to boulders) of unit Qmsc, which are recognized on the basis of their high backscatter and, in some cases, their moderate seafloor relief (sheets 1, 2, 3), are found most prominently in a large (about 0.75 km2) lobe that is present from about 1,800 to 3,600 m offshore of the mouth of Arroyo Burro, in water depths of about 36 to 65 m. The lobe is inferred to consist of coarse-grained sediment (coarse sand to boulders) that is resistant to erosion. Although these coarse-grained deposits almost certainly are derived from Arroyo Burro, the lobe could represent either the underflow deposits of late Holocene floods or a relict geomorphologic feature, having been deposited in shallower marine deltaic (or even alluvial?) environments at lower sea levels in the latest Pleistocene and early Holocene. Unit Qmsc also is present in shallower water (depths of about 10 to 20 m), most notably in a small area (approximately 0.09 km2) that extends offshore from Montecito Creek, in the eastern part of the map area. The presence of coarser grained sediment (coarse sand and possibly gravel) also is inferred in shallower water (depths of 10 to 20 m) offshore from Arroyo Burro, but these deposits are mapped as unit Qmss because they are found within arcuate scour depressions that have been referred to as "rippled scour depressions" (see, for example, Cacchione and others, 1984; Phillips, 2007) or "sorted bedforms" (see, for example, Murray and Thieler, 2004; Goff and others, 2005; Trembanis and Hume, 2011). Although the general area in which Qmss scour depressions are found is not likely to change substantially, the boundaries of the unit(s), as well as the locations of individual depressions and their intervening flat sand sheets, likely are ephemeral, changing during significant storm events. Hydrocarbon-seep-induced topography, which is present most prominently along the axis of anticlines, includes many features (described by Keller and others, 2007) along the trend of the Mid-Channel Anticline, about 10 km south of the map area in the Santa Barbara Channel. Geologic map units associated with hydrocarbon emissions in the map area include grouped to solitary pockmarks (unit Qmp) and asphalt (tar) deposits (unit Qas), as well as areas of undifferentiated hydrocarbon-related features (unit Qhfu) that probably include a mix of mounds, mud volcanoes, pockmarks, carbonate mats, and other constructional and erosional "seabed forms" (see Keller and others, 2007), all of which are superimposed on consolidated, undivided Miocene and Pliocene bedrock (unit Tbu). Offshore bedrock exposures are assigned to the Miocene Monterey Formation (unit Tm) and to the undivided Miocene and Pliocene bedrock unit (Tbu), primarily on the basis of extrapolation from the onland geologic mapping of Minor and others (2009), as well as the geologic cross sections of Redin (2005). These cross sections, which are constrained by industry seismic-reflection data and petroleum well logs, suggest that a considerable part of the undivided bedrock unit may belong to the Pliocene and Pleistocene Pico Formation. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tbu or Qms/Tm, are interpreted as ephemeral sediment layers that may or may not be continuously present, depending on storms, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. The Santa Barbara Channel region, including the map area, has a long history of petroleum production (Barnum, 1998). The Monterey Formation is the primary petroleum-source rock in the Santa Barbara Channel, and the Pico Formation is one of the primary petroleum reservoirs. The bedrock units typically are exposed in structural highs that include uplifts associated with the partly blind(?), south-dipping Rincon Creek Fault Zone and the outer shelf anticlinal uplift that developed above the south strand of the Red Mountain Fault in the southwestern part of the map area. The Offshore of Santa Barbara map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent GPS data suggest north-south shortening of about 6 mm/yr (Larson and Webb, 1992). The active, east-west-striking Red Mountain and Rincon Creek Faults and their related folds are some of the structures on which this shortening occurs. This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara Basins and represents an important earthquake hazard (see, for example, Fisher and others, 2009). Very high uplift rates of onland marine terraces from More Mesa (2.2 mm/yr), in the western part of the map area, to Summerland (0.7 mm/yr), a few kilometers east of the map area, are further indication of rapid shortening in this region (Keller and Gurrola, 2000). A map that shows these data is published in Scientific Investigations Map 3281, "California State Waters Map Series--Offshore of Santa Barbara, California." This layer is part of USGS Data Series 781.

This polygon shapefile contains geologic features of the offshore area of Carpinteria, California. The offshore part of the map area largely consists of a relatively shallow (less than about 45 m deep), gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (unit Qms) at depths less than about 25 m and, at depths greater than about 25 m, are the more fine-grained sediments (very fine sand, silt, and clay) of unit Qmsf. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying (see sheet 6). It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Coarser grained deposits (coarse sand to boulders) of unit Qmsc, which are recognized on the basis of their moderate seafloor relief and high basckscatter (sheet 3), as well as camera observations (sheet 6) and sampling (Reid and others, 2006; Barnard and others, 2009), are found locally in water depths less than about 15 m, except offshore of Rincon Point where they extend to depths of about 21 m. The largest Qmsc deposits are present at the mouths of Rincon Creek and Toro Canyon Creek. The convex seafloor relief of these coarse-grained deposits suggests that they are wave-winnowed lags that armor the seafloor and are relatively resistant to erosion. The sediments may, in part, be relict, having been deposited in shallower marine (or even alluvial?) environments at lower sea levels in the latest Pleistocene and Holocene; this seems especially likely for the arcuate lobe of unit Qmsc that extends 1,700 m offshore from Rincon Point. The Qmsc deposits offshore of Toro Canyon Creek are found adjacent to onshore alluvial and alluvial fan deposits (Minor and others, 2009) and, thus, may have formed as distal-alluvial or fan-delta facies of that system. Offshore bedrock exposures are assigned to the Miocene Monterey Formation (unit Tm) and the Pliocene and Pleistocene Pico Formation (unit QTp), primarily on the basis of extrapolation from the onshore mapping of Tan and others (2003a,b), Tan and Clahan (2004), and Minor and others (2009), as well as the cross sections of Redin and others (1998, 2004) that are constrained by industry seismic-reflection data and petroleum well logs. Where uncertainty exists, bedrock is mapped as an undivided unit (QTbu). These strata are exposed in structural highs that include the Rincon Anticline and uplifts bounded by the Rincon Creek Fault and by the north and south strands of the Red Mountain Fault. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tm, Qms/QTbu, or Qms/QTp, are interpreted as ephemeral sediment layers that may or may not be continuously present, whose presence or absence is a function of the recency and intensity of storm events, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. Two offshore anthropogenic units also are present in the map area, each related to offshore hydrocarbon production. The first (unit af) consists of coarse artificial fill associated with construction of the Rincon Island petroleum-production facility near the east edge of the map area. The second (unit pd) consists of coarse artificial fill mixed with sediment and shell debris, mapped in outcrops surrounding Rincon Island and at the locations of former oil platforms "Heidi," "Hope," "Hazel," and "Hilda" from the Summerland and Carpinteria oil fields (Barnum, 1998). The Monterey Formation is the primary petroleum-source rock in the Santa Barbara channel, and the Pico Formation is one of the primary petroleum reservoirs. The Offshore of Carpinteria map area is in the Ventura Basin, in the southern part of the Western Transverse Ranges geologic province, which is north of the California Continental Borderland (Fisher and others, 2009). This province has undergone significant north-south compression since the Miocene, and recent GPS data suggest north-south shortening of about 6 to 10 mm/yr (Larson and Webb, 1992; Donnellan and others, 1993). The active, east-west-striking, north-dipping Pitas Point Fault (a broad zone that includes south-dipping reverse-fault splays), Red Mountain Fault, and Rincon Creek Fault are some of the structures on which this shortening occurs (see, for example, Jackson and Yeats, 1982; Sorlien and others, 2000). This fault system, in aggregate, extends for about 100 km through the Ventura and Santa Barbara Basins and represents an important earthquake hazard.

This part of SIM 3302 presents data for the geologic and geomorphic map (see sheet 10, SIM 3302) of the Offshore of Coal Oil Point map area, California. The vector data file is included in "Geology_OffshoreCoalOilPoint.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshoreCoalOilPoint/data_catalog_OffshoreCoalOilPoint.html. The offshore part of the Offshore of Coal Oil Point map area largely consists of a gently offshore-dipping (less than 1 degree) shelf underlain by sediments derived primarily from relatively small coastal watersheds that drain the Santa Ynez Mountains. Shelf deposits are primarily sand (Qms) at depths less than about 35 to 50 m, and they are finer grained sediment such as very fine sand, silt, and clay (Qmsf) from depths of 35 to 50 m southward to the shelf break at a depth of about 90 m. The boundary between units Qms and Qmsf is based on observations and extrapolation from sediment sampling (see, for example, Reid and others, 2006) and camera ground-truth surveying. It is important to note that the boundary between units Qms and Qmsf should be considered transitional and approximate and is expected to shift as a result of seasonal- to annual- to decadal-scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits that are similar to unit Qmsf also are mapped at water depths greater than 90 m, below the shelf break on the upper slope; however, here they are identified as a separate unit (unit Qmsl) because of their location below the distinct shelf-slope geomorphologic break. Coarser grained, marine deposits (coarse sand to boulders) of units Qmsc, Qmscl, and Qsc are recognized on the basis of their high acoustic backscatter, their ground-truth-survey imagery, and, in some cases, their moderate seafloor relief. This coarse-grained facies is linked either to the mouths of steep coastal watersheds or to adjacent seafloor bedrock outcrops, and the deposits generally represent wave-winnowed lags of deltaic sediment. Two distinct lobes of coarse-grained sediment (unit Qmscl), present in deeper water (about 50 m) near the west edge of the map area, may similarly represent winnowed deltaic deposits that formed at lower sea levels during the latest Pleistocene or early Holocene. An isolated patch of clast-supported cobbles (unit Qsc), which rests on bedrock south of Coal Oil Point at a water depth of 70 m, also may have been deposited at lower sea levels during the late Pleistocene. Offshore bedrock exposures are mapped as either the Miocene Monterey Formation (Tm, Tmu, Tmm), the late Miocene and early Pliocene Sisquoc Formation (Tsq), or the undivided Quaternary and Tertiary bedrock (QTbu) or undivided Tertiary bedrock (Tbu) units on the basis of the confidence in extending the onshore mapping of Minor and others (2009) offshore. Midshelf to outer shelf bedrock exposures are all mapped as undivided units; however, offshore sampling data (see, for example, Kunitomi and others, 1998), as well as regional cross sections that are constrained by petroleum exploration data and sampling (Redin, 2005; Redin and others, 2005), have suggested that these seafloor outcrops predominantly are late Miocene and Pliocene strata. These rocks have been uplifted in a large, regional, internally warped, south-dipping homocline that formed above the blind, north-dipping Pitas Point-North Channel Fault system; the fault tip is inferred to lie beneath the continental slope, about 6 to 7 km offshore. Bedrock is, in some places, overlain by a thin (less than 1 m?) veneer of sediment, recognized on the basis of high backscatter, flat relief, continuity with moderate- to high-relief bedrock outcrops, and (in some cases) high-resolution seismic-reflection data; these areas, which are mapped as composite units Qms/Tu, Qms/Tsq, Qms/Tmu, Qms/Tmm, Qms/Tm, Qms/Tbu, or Qmsf/QTbu, are interpreted as ephemeral sediment layers that may or may not be continuously present, whose presence or absence is a function of the recency and intensity of storm events, seasonal and (or) annual patterns of sediment movement, or longer term climate cycles. The Offshore of Coal Oil Point map area includes the upper part of the large (130 km2), well-documented submarine Goleta landslide complex (Eichhubl and others, 2002; Fisher and others, 2005; Greene and others, 2006). Greene and others (2006) reported that the complex, which measures 14.6 km long and 10.5 km wide and extends from water depths of 90 to 574 m, has displaced about 1.75 km3 of landslide debris during the Holocene; they described it as a compound, multiphase submarine landslide that contains both surficial slump blocks and mud flows, in three distinct segments (west, central, and east lobes). Each segment consists of a distinct headwall scarp (units Qglwh, Qglch, Qgleh), a downdropped head block (units Qglwb, Qglcb, Qgleb), and several composite slide-debris lobes (units Qglw5, Qfglw4, Qglw3, Qglw2, Qglw1, Qglc4, Qglc3, Qglc2a, Qglc2, Qfle5, Qgle4, Qgle3, Qgle2). The geologic map geomorphic map on sheet 10 (SIM 3302) shows the upper approximately 3 km of this landslide complex; in addition, the seismic-reflection profile SB-145 (fig. 3 on sheet 8, SIM 3302), which crosses the east lobe of the landslide complex, illustrates its subsurface characteristics. The landslide source is inferred to be Pleistocene-age, shelf-edge deltaic sediments deposited during Quaternary sea-level lowstands, and Fisher and others (2005) suggested that the youngest landslides formed about 8,000 to 10,000 years ago. The Santa Barbara Channel region, including the map area, has a long history of petroleum production (Barnum, 1998) that began in 1928 with discovery of the Ellwood oil field. Subsequent discoveries in the offshore part of the map area include the South Ellwood offshore oil field, the Coal Oil Point oil field, and the Naples oil and gas field (Brickey, 1998; Galloway, 1998). Oil and gas are mainly sourced by the Miocene Monterey Formation; the reservoirs are in the Vaqueros Formation, the Rincon Shale, and the Monterey Formation. Development of the South Ellwood offshore oil field began in 1966 from platform "Holly," which was the last platform to be installed in California's State Waters. Debris and infrastructure associated with platform "Holly," as well as with seep containment devices ("seep tents"), are mapped as unit pd. Hornafius and others (1999) described "the world's most spectacular marine hydrocarbon seeps" in the Coal Oil Point map area, and these seeps release an estimated 36 metric tons of methane and 17 metric tons reactive organic gas (ethane, propane, butane, and higher hydrocarbons) per day. Areas of grouped to solitary pockmarks (unit Qmp) caused by gas seeps are common features. In addition, numerous asphalt (tar) deposits (unit Qas) associated with hydrocarbon seeps and gas vents are mapped both onshore and offshore. The offshore deposits, which have been confirmed with seafloor video observations, often are localized along bedrock structures such as faults or the crests of anticlines, forming bathymetric features that are morphologically similar to bedrock outcrops but are distinguished from them on the basis of their low acoustic backscatter. Although many such asphalt deposits are too small to be shown on the map, the larger deposits can cover as much as several hundred square meters. References Cited: Barnum, H.P., 1998, Redevelopment of the western portion of the Rincon offshore oil field, Ventura, California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 201-215. Brickey, M.R., 1998, Oil and gas fields of the Santa Barbara Channel area, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, preface (2 p.). Eichhubl, P., Greene, H.G., and Maher, N., 2002, Physiography of an active transpressive margin basin--High-resolution bathymetry of the Santa Barbara basin, southern California continental borderland: Marine Geology, v. 184, p. 95-120. Fisher, M.A., Normark, W.R., Greene, H.G., Lee, H.J., and Sliter, R.W., 2005, Geology and tsunamigenic potential of submarine landslides in Santa Barbara Channel, southern California: Marine Geology, v. 224, p. 1-22. Galloway, J., 1998, Chronology of petroleum exploration and development in the Santa Barbara Channel area, offshore southern California, in Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, p. 1-12, 1 sheet. Greene, H.G., Murai, L.Y., Watts, P., Maher, N.A., Fisher, M.A., and Eichhubl, P., 2006, Submarine landslides in the Santa Barbara channel as potential tsunami sources: Natural Hazards and Earth System Sciences, v. 6, p. 63-88. Hornafius, J.S., Quigley, D.C., and Luyendyk, B.P., 1999, The world's most spectacular marine hydrocarbon seeps (Coal Oil Point, Santa Barbara Channel, California)--Quantification of emissions: Journal of Geophysical Research - Oceans, v. 104, p. 20,703-20,711. Kunitomi, D.S., Hopps, T.E., and Galloway, J.M., eds., 1998, Structure and petroleum geology, Santa Barbara Channel, California: American Association of Petroleum Geologists, Pacific Section, and Coast Geological Society, Miscellaneous Publication 46, 328 p. Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A., and Brandt, T.R., 2009, Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: U.S. Geological Survey Scientific Investigations Map 3001, scale

description: This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Aptos map area, California. The vector data file is included in "Geology_OffshoreAptos.zip," which is accessible from http://dx.doi.org/10.5066/F7K35RQB. Most of the offshore occupies very gently dipping (about 0.1 to 0.4 ) continental shelf, extending from the nearshore to water depths of about 70 m. In the southwestern part of the map, the shelf is incised by the north-trending head of Soquel Canyon, which has a maximum depth of 260 m on the south edge of the map. The shelf is underlain by late Neogene bedrock and a variably thick (as much as 32 m) late Quaternary sediment cover. Sea level has risen 120 to 130 m over about the last 21,000 years (for example, Stanford and others, 2011), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and transgressive erosion and deposition. Sea-level rise was apparently not steady during this period, leading to development of shoreline angles and adjacent submerged wave-cut platforms and risers (Kern, 1977). These features commonly are commonly removed by erosion or buried by shelf sediment, however their original morphology is at least partly preserved along the rim of upper Soquel Canyon. Geologic map units include three wave-cut platforms (units Qwp1, Qwp2, Qwp3) and risers (units Qwpr1, Qwpr2, Qwpr3), separated by shoreline angles at depths of approximately 96 to 100 m, 108 m, and 120 to 125 m. The deepest paleoshoreline (about 120 m deep) approximately corresponds to sea level during the final stages of the last sea-level lowstand (Stanford and others, 2011). Submergence during sea-level rise also cut off the direct connection between Soquel Canyon and coastal watersheds, rendering the submarine canyon relatively inactive. Although slightly sheltered in Monterey Bay, the Offshore of Aptos map area is now subjected to significant wave energy and strong currents. Shelf morphology and geology are also affected by local faulting, folding, and uplift. The shelf in the Offshore of Aptos map area is cut by a diffuse zone of northwest-striking, steeply dipping to vertical faults mapped with high-resolution, seismic-reflection profiles. Faults are mapped on the basis of abrupt truncation or warping of reflections and (or) juxtaposition of reflection panels with different seismic parameters. Seismic profiles traversing this diffuse zone cross as many as 13 faults over a distance of 8 km. Mapped fault lengths in this diffuse zone are typically 2 to 7 km, and the strike of these offshore faults rotates from about 325 to 350 from southwest to northeast. Faults in this diffuse zone cut through Neogene bedrock and locally appear to disrupt overlying latest Quaternary sediments, and the presence of warped reflections along some fault strands suggests there may be both vertical and strike-slip offsets. This broad, distributed zone of deformation resembles the northwest-trending Monterey Bay Fault Zone (Greene, 1977, 1990), which occurs about 10 km farther west in outer Monterey Bay and similarly lacks a lengthy continuous "master fault." Deformation in both the Monterey Bay Fault zone and the diffuse zone of faults in the Offshore of Aptos map area is attributable to its location in the 40-km-wide, northward-narrowing structural zone between two major, right-lateral, strike-slip faults, the San Andreas Fault to the east and the offshore San Gregorio Fault to the west (McCulloch, 1987; Brabb, 1997; Wagner and others, 2002; Dickinson and others, 2005). Emergent late Pleistocene marine terraces on the south flank of the Santa Cruz Mountains in and north of northeastern Monterey Bay are as high as 125 m. Anderson and Menking (1994) report a 50- to 60-m elevation for the shoreline angle tied to the lowest emergent terrace (assigned to oxygen isotope stage 5c or 5e) in the Aptos vicinity, suggesting an uplift rate of about 0.4 to 0.6 mm/yr. Anderson (1990) and Anderson and Menking (1994) attributed this uplift to advection of crust around a bend in the San Andreas Fault, which lies 13 km northeast of the Aptos shoreline. The uplifted region in this tectonic model would include the nearshore and shelf of northeastern Monterey Bay, but there are considerable shore-normal uplift gradients and offshore uplift rates are not constrained. From La Selva Beach west to the western edge of the map area, the upper Miocene and Pliocene Purisima Formation (unit Tp; Powell and others, 2007) forms discontinuous outcrops that extend from coastal bluffs into the offshore to depths as great as 25 m. The seafloor outcrops are most prominent offshore of Soquel Point and have relatively low relief, probably in large part due to low structural dips. The Purisima Formation also forms outcrops in the steep walls of the head of Soquel Canyon. Other "hard bottom" in the map area is mapped at the location of a wastewater outfall pipe offshore of the mouth of the Pajaro River (artificial fill; unit af). Modern nearshore and inner- to mid-shelf sediments are mostly sand (unit Qms) and a mix of sand and gravel (units Qmsc and Qmsd). There is an extensive area in northeastern Monterey Bay where unit Tp bedrock is overlain a very thin cover of Qms; such areas are mapped and labeled as composite units (Qms/Tp) and shown with a stippled pattern on the map. Storlazzi and others (2011) showed that active sediment transport in the nearshore of northern Monterey Bay can lead to significant burial and exhumation of offshore bedrock reefs, and it is likely that the sediment cover in the mapped composite areas is ephemeral and transient. The more coarse-grained sands and gravels (units Qmsc and Qmsd) are primarily recognized on the basis of bathymetry and high backscatter. Unit Qmsc occurs only adjacent to bedrock at Soquel Point in water depths less than 20 m. Unit Qmsd forms erosional lags in scoured depressions at water depths ranging from about 10 to 25 m. The Qmsd depressions have irregular to lenticular outlines; are a few tens of centimeters deep; range in size from a few 10's to as much as about 54,000 m2; and are either bounded by relatively sharp and less commonly diffuse contacts with unit Qms sands, or by abrupt contacts with seafloor bedrock outcrops. Qmsd depressions are most abundant in a northeast-trending zone between Seacliff State Beach and La Selva Beach, where they form distinct, narrow (< 50 m) linear, bands that extend about 4 km offshore. Scour depressions similar to those mapped adjacent to bedrock near Soquel Point are common along this stretch of the California coast (see, for example, Hallenbeck and others, 2012; Davis and others, 2013). Such features have been referred to as "rippled-scour depressions" (see, for example, Cacchione and others, 1984) or "sorted bedforms" (see, for example, Goff and others, 2005; Trembanis and Hume, 2011). They form where surficial offshore sandy sediment is relatively thin (thus unable to fill the depressions) due to both low sediment supply and to erosion and transport of sediment during large ocean swells. The elongate, linear, shore-normal bands of scour depressions between Aptos and La Selva Beach are morphologically anomalous; this mode of occurrence has not been recognized elsewhere along the California coast. Although the general areas in which both unit Qmsd scour depressions and surrounding Qms sand sheets occur are not likely to change substantially, the boundaries of the unit(s) are likely ephemeral, changing seasonally and during significant storm events. An offshore transition from unit Qms to the more fine-grained marine sediments of unit Qmsf occurs at water depths of 25 to 30 m. Unit Qmsf is commonly extensively bioturbated and consists primarily of mud and muddy sand. Edwards (2002) and Grossman and others (2006) suggested these fine-grained sediments form an extensive "mid-shelf mud belt" that was primarily sourced by the San Lorenzo River, Pajaro River, and smaller coastal watersheds. A 4.3 km2 zone of hummocky seafloor (Qmsh) surrounded by fine-grained Qmsf occurs in the southeastern part of the map area at 30 to 35 m water depth, about 3 to 4 km north of the head of Soquel Canyon. Bathymetric contours reveal that the hummocky zone has an embayed up-slope margin, and relief on hummocks within the zone is as much as 100 cm over 100 m. The hummocky zone probably formed by liquefaction, and associated induced ground failure forced by strong ground motions from earthquakes. The embayed upper margin of the zone also indicates some slumping, surprising given the extremely gentle dip of the shelf (about 0.2 ) at this location. Earthquake sources for strong ground motions could include the distributed fault zone in northeastern Monterey Bay (several mapped faults cut the hummocky area) or the nearby San Andreas Fault (20 km to the northeast) or San Gregorio Fault (19 km to the southwest). Recent large earthquakes on the San Andreas Fault include the M 6.9 1989 Loma Prieta earthquake and the M 7.8 1906 Great California earthquake (Northern California Earthquake Data Center, 2014). Soquel Canyon is a tributary to the much larger Monterey Canyon system (Greene and others, 2002). The canyon axis plunges south about 4 ; side-canyon walls generally dip about 5 but are locally as steep as 20 to 25 . Non-bedrock geologic units in Soquel Canyon are largely defined and delineated on the basis of geomorphology. Unit Qcw represents mud and sand draped over the upper submarine canyon wall. Unit Qcfa represents the mainly mud fill of the inactive axial canyon channel. References Cited Anderson, R.S., 1990, Evolution of the northern Santa Cruz Mountains by advection of crust past a San Andreas Fault bend: Science, v. 249, p. 397-401. Anderson, R.S., and Menking, K.M., 1994, The Quaternary marine terraces of Santa Cruz, California-Evidence for coseismic uplift on two faults: Geological Society of America

This polygon shapefile contains geological features for the offshore area of Refugio Beach, California. The offshore Refugio Beach map area largely consists of a gently offshore-dipping (<1 degree) shelf (10 to ~ 90 m) underlain by sediments derived primarily from relatively small coastal watersheds draining the Santa Ynez Mountains. Nearshore and shelf deposits are primarily sand (Qms) at depths less than about 45 m and more fine-grained sediment - very fine sand, silt and clay (Qmsf), at depths greater than about 45 m. The boundary between Qms and Qmsf is based on observations and extrapolation from sediment sampling (for example, Reid and others, 2006) and camera groundtruthing. The Qms-Qmsf boundary is transitional and approximate, expected to shift based on seasonal to annual to decadal scale cycles in wave climate, sediment supply, and sediment transport. Fine-grained deposits similar to Qmsf also occur below the shelfbreak on the upper slope at water depths greater than 90 m, where they are broken out as a separate unit (Qmsl) based on their location and geomorphology. More coarse-grained deposits recognized on the basis of high backscatter and in some cases moderate seafloor relief have two modes of occurrence. In the relative nearshore (10 to 30 m water depth), coarse-grained strata (Qmsc) underlie laterally coalescing and discontinuous bars at the mouths of steep coastal watersheds. Coarser-grained sediments also form several distinct lobes (Qmscl) in water depths of 25 to 70 m, about 600 to 3,000 m offshore. The lobes range in size from ~100,000 m2 to ~1.5 km2 and are mapped on the basis of high backscatter and subtle positive seafloor relief. These coarse-grained strata were clearly derived from fluvial point sources in the adjacent, steep Santa Ynez Mountains. Bedrock exposures in the nearshore west of El Capitan are assigned to the Miocene Monterey Formation based on proximity to coastal outcrops mapped by Dibblee (1981a, b). Much of the outer shelf (water depths greater than 70 m) is also underlain by undifferentiated Tertiary bedrock (Tbu). Based on the regional cross sections constrained by deep seismic-reflection data and borehole logs (Heck, 1998; Tennyson and Kropp, 1998; Forman and Redin, 2005; Redin, 2005) and high-resolution seismic-reflection data coupled with proprietary oil industry dartcore data (Ashley, 1977), these outer-shelf outcrops consist of the Miocene Sisquoc Formation and the Pliocene Repetto and Pico Formations. These rocks have been uplifted in a large, warped, regional south-dipping homocline that formed above the blind, north-dipping North Channel fault. The fault tip is inferred at about 1.5 sec TWT (~2 km) about 6 to 7 km offshore, beneath the slope and just outside California's State Waters. Bedrock that underlies some parts of the shelf is overlain by a thin (< 1 m?) sediment veneer, recognized based on high backscatter, flat relief, continuity with moderate to high relief bedrock outcrops, and (in some cases) high-resolution, seismic-reflection data (Qms/Qtbu. Qms/Tbu, Qms/Tm). These sediment layers are likely ephemeral - they may or may not be present based on storms, seasonal/annual patterns of sediment movement, or longer-term climate cycles. This area has a long history of petroleum production (Barnum, 1998), and grouped to solitary pockmarks (Qmp) caused by gas seeps are common features in the offshore Refugio map area. Shell discovered the Molino gas field in 1962, 4 km offshore in the southwest part of the map area. Production, by onshore directional drilling of an anticlinal trap, has been underway since the 1960's (Galloway, 1998). A map that show these data are published in Scientific Investigations Map 3319, "California State Waters Map Series--Offshore of Refugio Beach, California." This layer is part of USGS Data Series 781.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore of Point Reyes map area, California. The vector data file is included in "Geology_OffshorePointReyes.zip," which is accessible from http://pubs.usgs.gov/ds/781/OffshorePointReyes/data_catalog_OffshorePointReyes.html. Marine geology and geomorphology was mapped in the Offshore of Point Reyes map area from approximate Mean High Water (MHW) to the 3-nautical-mile limit of Californiaâ  s State Waters. MHW is defined at an elevation of 1.46 m above the North American Vertical Datum of 1988 (NAVD 88) (Weber and others, 2005). Offshore geologic units were delineated on the basis of integrated analyses of adjacent onshore geology with multibeam bathymetry and backscatter imagery, seafloor-sediment and rock samples (Reid and others, 2006), digital camera and video imagery, and high-resolution seismic-reflection profiles. The onshore bedrock mapping was compiled from Galloway (1977), Clark and Brabb (1997), and Wagner and Gutierrez (2010). Quaternary mapping was compiled from Witter and others (2006) and Wagner and Gutierrez (2010), with unit contacts modified based on analysis of 2012 LiDAR imagery; and additional Quaternary mapping by M.W. Manson. The morphology and the geology of the Offshore of Point Reyes map area result from the interplay between tectonics, sea-level rise, local sedimentary processes, and oceanography. The Point Reyes Fault Zone runs through the map area and is an offshore curvilinear reverse Fault Zone (Hoskins and Griffiths, 1971; McCulloch, 1987; Heck and others, 1990; Stozek, 2012) that likely connects with the western San Gregorio fault further to the south (Ryan and others, 2008), making it part of the San Andreas Fault System. The Point Reyes Fault Zone is characterized by a 5 to 11 km-wide zone that is associated with two main fault structures, the Point Reyes Fault and the Western Point Reyes Fault (fig. 1). Tectonic influences impacting shelf morphology and geology are related to local faulting, folding, uplift, and subsidence. Granitic basement rocks are offset about 1.4 km on the Point Reyes thrust fault offshore of the Point Reyes headland (McCulloch, 1987), and this uplift combined with west-side-up offset of the San Andreas Fault (Grove and Niemi, 2005) resulted in uplift of the Point Reyes Peninsula, including the adjacent Bodega and Tomales shelf. The Western Point Reyes Fault is defined by a broad anticlinal structure visible in both industry and high-resolution seismic datasets and exhibits that same sense of vergence as the Point Reyes Fault. The deformation associated with north-side-up motion across the Point Reyes Fault Zone has resulted in a distinct bathymetric gradient across the Point Reyes Fault, with a shallow bedrock platform to the north and east, and a deeper bedrock platform to the south. Late Pleistocene uplift of marine terraces on the southern Point Reyes Peninsula suggests active deformation west of the San Andreas Fault (Grove and others, 2010) on offshore structures. The Point Reyes Fault and related structures may be responsible for this recent uplift of the Point Reyes Peninsula, however, the distribution and age control of Pleistocene strata in the Offshore of Point Reyes map area is not well constrained and therefore it is difficult to directly link the uplift onshore with the offshore Point Reyes Fault structures. Pervasive stratal thinning within inferred uppermost Pliocene and Pleistocene (post-Purisima) units above the Western Point Reyes Fault anticline suggests Quaternary active shortening above a curvilinear northeast to north-dipping Point Reyes Fault zone. Lack of clear deformation within the uppermost Pleistocene and Holocene unit suggests activity along the Point Reyes Fault zone has diminished or slowed since 21,000 years ago. In this map area the cumulative (post-Miocene) slip-rate on the Point Reyes Fault Zone is poorly constrained, but is estimated to be 0.3 mm/yr based on vertical offset of granitic basement rocks (McCulloch, 1987; Wills and others, 2008). With the exception of the bathymetric gradient across the Point Reyes Fault, the offshore part of this map area is largely characterized by a relatively flat (<0.8à °) bedrock platform. The continental shelf is quite wide in this area, with the shelfbreak located west of the Farallon high , about 35 km offshore. Sea level has risen about 125 to 130 m over about the last 21,000 years (for example, Lambeck and Chappell, 2001; Peltier and Fairbanks, 2005), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and associated transgressive erosion and deposition (for example, Catuneanu, 2006). Land-derived sediment was carried into this dynamic setting, and then subjected to full Pacific Ocean wave energy and strong currents before deposition or offshore transport. Much of the inner shelf bedrock platform is composed of Tertiary marine sedimentary rocks, which are underlain by Salinian granitic and metamorphic basement rocks, including the Late Cretaceous porphyritic granite (unit Kgg), which outcrops on the seafloor south of the Point Reyes headland. Unit Kgg appears complexly fractured, similar to onshore exposures, with a distinct massive, bulbous texture in multibeam imagery. The Tertiary strata overlying the granite form the core of the Point Reyes syncline (Weaver, 1949) and include the early Eocene Point Reyes Conglomerate (unit Tpr), mid- to late Miocene Monterey Formation (unit Tm), late Miocene Santa Margarita Formation (unit Tsm), late Miocene Santa Cruz Mudstone (unit Tsc), and late Miocene to early Pliocene Purisima Formation (unit Tp). The Point Reyes Conglomerate is exposed on the seafloor adjacent to onshore outcrops on the Point Reyes headland and has a distinct massive texture with some bedding planes visible, but the strata are highly fractured. Based on stratigraphic correlations from seismic reflection data and onshore wells, combined with multibeam imagery, we infer rocks of the early Eocene Point Reyes Conglomerate extend at least 6 km northwest from onshore exposures at Point Reyes headland. The absence of unit Tsc in onshore wells (Clark and Brabb, 1997) suggests these rocks are unlikely to occur within the Tertiary section of this map area, north of the Point Reyes Fault. In this map area, unit Tu represents seafloor outcrops of a middle Miocene to upper Pliocene sequence overlying unit Tpr, that may include units Tm, Tsm, and Tp. Seafloor exposures of unit Tu are characterized by distinct rhythmic bedding where beds are dipping and by a mottled texture where those beds become flat-lying. Modern nearshore sediments are mostly sand (unit Qms and Qsw) and a mix of sand, gravel, and cobbles (units Qmsc and Qmsd). The more coarse-grained sands and gravels (units Qmsc and Qmsd) are primarily recognized on the basis of bathymetry and high backscatter. The emergent bedrock platform north and west of the Point Reyes headland is heavily scoured, resulting in large areas of unit Qmsc and associated Qmsd. Both Qmsc and Qmsd typically have abrupt landward contacts with bedrock and form irregular to lenticular exposures that are commonly elongate in the shore-normal direction. Contacts between units Qmsc and Qms are typically gradational. Unit Qmsd forms erosional lags in scoured depressions that are bounded by relatively sharp and less commonly diffuse contacts with unit Qms horizontal sand sheets. These depressions are typically a few tens of centimeters deep and range in size from a few 10's of meters to more than 1 km2. There is an area of high-backscatter, and rough seafloor southeast of the Point Reyes headland that is notable in that it includes several small, irregular "lumps", with as much as 1 m of positive relief above the seafloor (unit Qsr). Unit Qsr occurs in water depths between 50 and 60 meters, with individual lumps randomly distributed to west-trending. This area on seismic-reflection data shows this lumpy material rests on several meters of latest Pleistocene to Holocene sediment and is thus not bedrock outcrop. Rather, it seems likely that this lumpy material is marine debris, possibly derived from one (or more) of the more than 60 shipwrecks offshore of the Point Reyes Peninsula between 1849 and 1940 (National Park Service, 2012). It is also conceivable that this lumpy terrane consists of biological "hardgrounds". Video transect data crossing unit Qsr near the Point Reyes headland was of insufficient quality to distinguish between these above alternatives. A transition to more fine-grained marine sediments (unit Qmsf) occurs around 50â  60 m depth within most of the map area, however, directly south and east of Drakes Estero, backscatter and seafloor sediment samples (Chin and others, 1997) suggest fine-grained sediments extend into water depths as shallow as 30 m. Unit Qmsf is commonly extensively bioturbated and consists primarily of mud and muddy sand. These fine-grained sediments are inferred to have been derived from the Drakes Estero estuary or from the San Francisco Bay to the south, via predominantly northwest flow at the seafloor (Noble and Gelfenbaum, 1990). References Cited Catuneanu, O., 2006, Principles of Sequence Stratigraphy: Amsterdam, Elsevier, 375 p. Chin, J.L., Karl, H.A., and Maher, N.M., 1997, Shallow subsurface geology of the continental shelf, Gulf of the Farallones, California, and its relationship to surficial seafloor characteristics: Marine Geology, v. 137, p. 251-269. Clark, J.C., and Brabb, E.E., 1997, Geology of the Point Reyes National Seashore and vicinity: U.S. Geological Survey Open-File Report 97-456, scale 1:48,000. Galloway, A.J., 1977, Geology of the Point Reyes Peninsula Marin County, California: California Geological Survey Bulletin 202, scale 1:24,000. Grove, K. and Niemi, T., 2005, Late Quaternary deformation and slip rates in the northern San

Fractures serve as important conduits for subsurface fluid flow and their presence can transform an otherwise unproductive rock formation into an economic hydrocarbon reservoir. Large through going fracture zones are targeted for wellbore intersection because of their high transmissivity and ability to drain a large volume of reservoir rock. On the other hand, gouge filled faults may serve as permeability barriers that inhibit flow to the wellbore. Thus, fractures represent major heterogeneities within the reservoir. Predicting the spatial distribution and fluid flow properties of fracture systems in the subsurface is an integral component of reservoir characterization, and is the primary goal of our research project. Work to date can be divided into two main efforts: (1) evaluating the effects of mechanical stratigraphy on fracture scaling relations, and (2) spatial analysis of secondary porosity from limestone core. In the first project, we are analyzing veins (mineral-filled fractures) at the microscopic scale from samples taken from an outcrop of the Monterey Formation, California. Samples were collected from various stratigraphic layers, as well as at different structural positions around a small fold. We are also quantifying the fracture-related porosity from digital images of thin sections. This will enable us to map the distribution of porosity and fracture permeability around the fold, thus providing important constraints on fluid flow in subsurface reservoirs. In the microstructural analysis of fracture aperture, fracture length, and fracture related strain, we have analyzed 18 samples by conducting 1770 scanline surveys of digital images. The image processing software we are employing allows for the rapid collection of fracture aperture, length and spacing measurements as well as for their direct transfer into spreadsheets. A total of 15,766 individual measurements have been taken from these samples. The dataset will provide the opportunity to address a wide range of important issues, such as the ability to predict rock properties beyond the scale of observation, factors that lead to breaks in scaling relations, and fluid flow through fractured rock masses. For the second research component, we are characterizing the distribution and geometry of solution-enhanced pores in limestones, an important reservoir rock that is notorious for its irregular production history. Using a GIS (Geographic Information System) software package, we are mapping the density of pores, pore geometry and pore size from a 30 foot section of the Biscayne aquifer. The Biscayne aquifer is a porous limestone that serves as the primary source of water for the rapidly growing population of South Florida. Preliminary results reveal a heterogeneous distribution of pore density, which can be directly related to stratigraphic layering in the limestone. Further analysis will quantify the extent of high-density pore zones, and their contribution to enhanced fluid flow.

This part of DS 781 presents data for the geologic and geomorphic map of the Offshore Santa Cruz map area, California. The vector data file is included in "Geology_OffshoreSantaCruz.zip," which is accessible from http://dx.doi.org/10.5066/F7TM785G. The offshore part of the map area lies south and southwest of the southwest flank of the Santa Cruz Mountains, on the open Pacific Coast and in northwestern Monterey Bay. This offshore area extends from the shoreline across the gently dipping (about 0.7° to 0.8°) continental shelf to water depths of about 75 to 90 m at the outer limit of California's State Waters. The shelf is underlain by Neogene bedrock and a variably thick (as much as 32 m) late Quaternary sediment cover. Sea level has risen 120 to 130 m over about the last 21,000 years (for example, Stanford and others, 2011), leading to broadening of the continental shelf, progressive eastward migration of the shoreline and wave-cut platform, and associated transgressive erosion and deposition (for example, Catuneanu, 2006). The Offshore of Santa Cruz map area is now subjected to full, and sometimes severe, wave energy and strong currents. Shelf morphology and geology are also affected by local faulting, folding, and uplift. The western part of the offshore map area is cut by the northern part of the diffuse, northwest-striking, about 5-km-wide Monterey Bay Fault Zone (Greene, 1990). Mapping, based on seismic-reflection profiles, reveals that the zone can include as many as ten or more vertical to steeply dipping strands, which range in length from about 1 to 9 km in the map area. Greene (1990) suggested the fault zone may have both vertical and strike-slip offset based on the presence of warped reflections along some fault strands. Fault-related deformation clearly affects Neogene bedrock, but faults in this zone do not appear to offset Quaternary deposits. The Monterey Bay Fault Zone lies subparallel to the active San Gregorio Fault Zone (McCulloch, 1987; Dickinson and others, 2005), which extends through the southwest corner of the map area (outside California's State Waters) and has an estimated 156 km of right-lateral offset. The northwest-trending, strike-slip deformation associated with the San Gregorio and Monterey Bay Fault Zones appears to largely postdate deformation along the north-trending Ben Lomond Fault. Stanley and McCaffrey (1983) used gravity anomalies to extend mapping of the Ben Lomond fault for 3 km from bedrock exposures in the Santa Cruz Mountains beneath emergent marine terrace deposits to the shoreline about 930 m west of Point Santa Cruz. This onshore-offshore geologic map shows the fault extending an additional 4 km to the south in the offshore, based on interpretation of high-resolution bathymetry and seismic-reflection data. Emergent marine terraces on the flanks of the Santa Cruz Mountains in and north of Santa Cruz are as high as 240 m with estimated uplift rates that range from about 0.2 mm/year (for example, Bradley and Griggs, 1976; Lajoie and others, 1991) to as much as 1.1 mm/yr (for example, Perg and others, 2001). This uplift has been attributed to a combination of (1) advection of crust around a bend in the San Andreas Fault, and (2) uplift on the northeast (landward) side of a steep-northeast dipping offshore San Gregorio fault (Anderson, 1990; Anderson and Menking, 1994). The uplifted region in this tectonic model includes the nearshore and shelf of the Offshore of Santa Cruz map area, but probable shore-normal uplift gradients are associated with both processes and offshore uplift rates are not well constrained. From the northern edge of the map area south to western Santa Cruz (about 1400 m west of Point Santa Cruz (fig. 1-2), the upper Miocene Santa Cruz Mudstone (unit Tsc) forms continuous outcrops that extend from coastal bluffs into the offshore to depths as great as 35 m. To the southeast, similar continuous onshore-to-offshore outcrops of the younger (Pliocene and late Miocene) Purisima Formation (unit Tp; Powell and others, 2007) extend southwest from bluffs at Point Santa Cruz and east of the mouth of the San Lorenzo River. The Santa Cruz Mudstone (Tsc) seafloor outcrops are characterized by differentially eroded layers (harder and softer interbeds) that are folded and densely fractured, creating a relatively "shattered" appearance on shaded relief maps. The adjacent seafloor outcrops of the Purisima Formation (Tp) are similarly folded but have less distinct and more diffuse bedding surfaces (in part due to lower dips) and are notably less fractured, and thus have a distinctly different seafloor geomorphic expression. Modern nearshore and inner- to mid-shelf sediments are mostly sand (unit Qms) and a mix of sand and gravel (units Qmsc and Qmsd). In addition to its presence on the broad shelf, unit Qms notably occurs in well-defined paleocha... Visit https://dataone.org/datasets/22df24ad-d8f3-4e06-a96d-3974e4f2e7ab for complete metadata about this dataset.