no abstract provided

This tile service is derived from a digital raster graphic of the historical 15-minute USGS topographic quadrangle maps of coastal towns in Massachusetts. These quadrangles were mosaicked together to create a single data layer of the coast of Massachusetts and a large portion of the southeastern area of the state.The Massachusetts Office of Coastal Zone Management (CZM) obtained the map images from the Harvard Map Collection. The maps were produced in the late 1890s and early 20th century at a scale of 1:62,500 or 1:63,360 and are commonly known as 15-minute quadrangle maps because each map covers a four-sided area of 15 minutes of latitude and 15 minutes of longitude.

Geologic, sediment texture, and physiographic zone maps characterize the sea floor south and west of Martha's Vineyard and north of Nantucket, Massachusetts. These maps were derived from interpretations of seismic-reflection profiles, high-resolution bathymetry, acoustic-backscatter intensity, bottom photographs, and surficial sediment samples. The interpretation of the seismic stratigraphy and mapping of glacial and Holocene marine units provided a foundation on which the surficial maps were created. This mapping is a result of a collaborative effort between the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management to characterize the surface and subsurface geologic framework offshore of Massachusetts.

A dataset listing Massachusetts cities by population for 2024.

Geologic, sediment texture, and physiographic zone maps characterize the sea floor south and west of Martha's Vineyard and north of Nantucket, Massachusetts. These maps were derived from interpretations of seismic-reflection profiles, high-resolution bathymetry, acoustic-backscatter intensity, bottom photographs, and surficial sediment samples. The interpretation of the seismic stratigraphy and mapping of glacial and Holocene marine units provided a foundation on which the surficial maps were created. This mapping is a result of a collaborative effort between the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management to characterize the surface and subsurface geologic framework offshore of Massachusetts.

April 2022

Yucca Mountain, Nye County, Nevada, has been identified as a potential site for underground storage of high-level radioactive waste. This geologic map compilation, including all of Yucca Mountain and Crater Flat, most of the Calico Hills, western Jackass Flats, Little Skull Mountain, the Striped Hills, the Skeleton Hills, and the northeastern Amargosa Desert, portrays the geologic framework for a saturated-zone hydrologic flow model of the Yucca Mountain site. Key geologic features shown on the geologic map and accompanying cross sections include: (1) exposures of Proterozoic through Devonian strata inferred to have been deformed by regional thrust faulting and folding, in the Skeleton Hills, Striped Hills, and Amargosa Desert near Big Dune; (2) folded and thrust-faulted Devonian and Mississippian strata, unconformably overlain by Miocene tuffs and lavas and cut by complex Neogene fault patterns, in the Calico Hills; (3) the Claim Canyon caldera, a segment of which is exposed north of Yucca Mountain and Crater Flat; (4) thick densely welded to nonwelded ash-flow sheets of the Miocene southwest Nevada volcanic field exposed in normal-fault-bounded blocks at Yucca Mountain; (5) upper Tertiary and Quaternary basaltic cinder cones and lava flows in Crater Flat and at southernmost Yucca Mountain; and (6) broad basins covered by Quaternary and upper Tertiary surficial deposits in Jackass Flats, Crater Flat, and the northeastern Amargosa Desert, beneath which Neogene normal and strike-slip faults are inferred to be present on the basis of geophysical data and geologic map patterns. A regional thrust belt of late Paleozoic or Mesozoic age affected all pre-Tertiary rocks in the region; main thrust faults, not exposed in the map area, are interpreted to underlie the map area in an arcuate pattern, striking north, northeast, and east. The predominant vergence of thrust faults exposed elsewhere in the region, including the Belted Range and Specter Range thrusts, was to the east, southeast, and south. The vertical to overturned strata of the Striped Hills are hypothesized to result from successive stacking of three south- vergent thrust ramps, the lowest of which is the Specter Range thrust. The CP thrust is interpreted as a north-vergent backthrust that may have been roughly contemporaneous with the Belted Range and Specter Range thrusts. The southwest Nevada volcanic field consists predominantly of a series of silicic tuffs and lava flows ranging in age from 15 to 8 Ma. The map area is in the southwestern quadrant of the southwest Nevada volcanic field, just south of the Timber Mountain caldera complex. The Claim Canyon caldera, exposed in the northern part of the map area, contains thick deposits of the 12.7-Ma Tiva Canyon Tuff, along with widespread megabreccia deposits of similar age, and subordinate thick exposures of other 12.8- to 12.7-Ma Paintbrush Group rocks. An irregular, blocky fault array, which affects parts of the caldera and much of the nearby area, includes several large-displacement, steeply dipping faults that strike radially to the caldera and bound south-dipping blocks of volcanic rock. South and southeast of the Claim Canyon caldera, in the area that includes Yucca Mountain, the Neogene fault pattern is dominated by closely spaced, north-northwest- to north- northeast-striking normal faults that lie within a north- trending graben. This 20- to 25-km-wide graben includes Crater Flat, Yucca Mountain, and Fortymile Wash, and is bounded on the east by the "gravity fault" and on the west by the Bare Mountain fault. Both of these faults separate Proterozoic and Paleozoic sedimentary rocks in their footwalls from Miocene volcanic rocks in their hanging walls. Stratigraphic and structural relations at Yucca Mountain demonstrate that block-bounding faults were active before and during eruption of the 12.8- to 12.7-Ma Paintbrush Group, and significant motion on these faults continued until after the 11.6-Ma Rainier Mesa Tuff was deposited. North of Crater Flat, in and near the Claim Canyon caldera, most of the tilting of the volcanic section predated the 11.6-Ma Rainier Mesa Tuff. In contrast, geologic relations in central and southern Yucca Mountain indicate that much of the stratal tilting there occurred after 11.6 Ma, probably synchronous with the main pulse of vertical-axis rotation that occurred between 11.6 and 11.45 Ma. Beneath the broad basins, such as Crater Flat, Jackass Flats, and the Amargosa Desert, faults are inferred from geophysical data. Geologic and geophysical data imply the presence of the large-offset, east-west-striking Highway 95 fault beneath surficial deposits along the northeast margin of the Amargosa Desert, directly south of Yucca Mountain and Crater Flat. The Highway 95 fault is interpreted to be downthrown to the north, with a component of dextral displacement. It juxtaposes a block of Paleozoic carbonate rock overlain by a minimal thickness of Tertiary rocks (to the south) against the Miocene volcanic section of Yucca Mountain (to the north). Alluvial geomorphic surfaces compose the bulk of Quaternary surficial units in the Yucca Mountain region. Deposits associated with these surfaces include alluvium, colluvium, and minor eolian and debris-flow sediments. Photogeologic and field studies locally have identified subtle fault scarps that offset these surfaces, and other evidence of Quaternary fault activity.

description: This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern Nevada. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic and tectonic interest. The Thirsty Canyon NW quadrangle is located in southern Nye County about 20 km west of the Nevada Test Site (NTS) and 30 km north of the town of Beatty. The map area is underlain by extensive layers of Neogene (about 14 to 4.5 million years old [Ma]) mafic and silicic volcanic rocks that are temporally and spatially associated with transtensional tectonic deformation. Mapped volcanic features include part of a late Miocene (about 9.2 Ma) collapse caldera, a Pliocene (about 4.5 Ma) shield volcano, and two Pleistocene (about 0.3 Ma) cinder cones. Also documented are numerous normal, oblique-slip, and strike-slip faults that reflect regional transtensional deformation along the southern part of the Walker Lane belt. The Thirsty Canyon NW map provides new geologic information for modeling groundwater flow paths that may enter the map area from underground nuclear testing areas located in the NTS about 25 km to the east. The geologic map database comprises six component ArcINFO map coverages that can be accessed after decompressing and unbundling the data archive file (tcnw.tar.gz). These six coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt) are formatted here in ArcINFO EXPORT format. Bundled with this database are two PDF files for readily viewing and printing the map, accessory graphics, and a description of map units and compilation methods.; abstract: This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, dike, and caldera wall), and point (i.e., structural attitude) vector data for the Thirsty Canyon NW 7 1/2' quadrangle in southern Nevada. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic and tectonic interest. The Thirsty Canyon NW quadrangle is located in southern Nye County about 20 km west of the Nevada Test Site (NTS) and 30 km north of the town of Beatty. The map area is underlain by extensive layers of Neogene (about 14 to 4.5 million years old [Ma]) mafic and silicic volcanic rocks that are temporally and spatially associated with transtensional tectonic deformation. Mapped volcanic features include part of a late Miocene (about 9.2 Ma) collapse caldera, a Pliocene (about 4.5 Ma) shield volcano, and two Pleistocene (about 0.3 Ma) cinder cones. Also documented are numerous normal, oblique-slip, and strike-slip faults that reflect regional transtensional deformation along the southern part of the Walker Lane belt. The Thirsty Canyon NW map provides new geologic information for modeling groundwater flow paths that may enter the map area from underground nuclear testing areas located in the NTS about 25 km to the east. The geologic map database comprises six component ArcINFO map coverages that can be accessed after decompressing and unbundling the data archive file (tcnw.tar.gz). These six coverages (tcnwpoly, tcnwflt, tcnwfold, tcnwdike, tcnwcald, and tcnwatt) are formatted here in ArcINFO EXPORT format. Bundled with this database are two PDF files for readily viewing and printing the map, accessory graphics, and a description of map units and compilation methods.

The Bayreuth sheet cuts into: the Bohemian massif with the Fichtel Mountains and the Upper Palatinate Forest, the Thuringian-Saxon and north-eastern Bavarian basement mountains and the southern German strata. Variscan folded rocks of the Precambrian to Lower Carboniferous are exposed in the southwest-northeast trending saddle and trough structures (Thuringian Synclinorian, Berga Anticlinorian & Vogtland Synclinorian) of the Thuringian-Saxon and Northeast Bavarian basement. The embedded complex of the Münchberger Gneissmasse represents a special feature: with its metamorphic rocks and its anchimetamorphic environment of Paleozoic layers in the Bavarian facies, it is both facies and tectonically in contrast to the surrounding Paleozoic in the Thuringian facies. In the center of the map sheet is the Fichtelgebirge with its Variscan granites and metamorphic pararocks (mica slate, gneisses, phyllites, quartzites). The Precambrian and Old Paleozoic sedimentary rocks were metamorphosed during the Variscan deformation. The Fichtelgebirge granites intruded post-Sudetic (330-310 ma) and post-Asturian (290-280 ma). In the area around Marktredwitz (Waldsassener Schiefergebirge) volcanic rocks pushed up in the Tertiary. While the Fichtelgebirge belongs to the Saxothuringian of the Variscids, the Upper Palatinate Forest in the southeast of the map sheet belongs to the Moldanubian. It is made up of metamorphites (gneiss, metabasite and anatexite) that emerged from the early Variscan overprint of Precambrian rocks. Here, too, extensive granitic plutonic rocks intruded in the Carboniferous. Slate Mountains and Bohemian Massif are cut off to the southwest by the Frankish Line, one of the major NW-SE fault zones in Central Europe. At the fault, the basement was z. T. lifted out more than 1000 m. In the south-west, the South German escarpment landscape with the Mesozoic of the East Bavarian Schollenland and the Franconian Jura joins. With its Jurassic sedimentary rocks, the Franconian Jura is one of the dominant mountain ranges in the southern German escarpment landscape. In addition to the legend, which provides information about the age, petrography and genesis of the units shown, three geological sections provide insights into the structure of the subsoil. In the northwest-southeast profile, the Franconian Forest, the Münchberg Gneiss Massif, the Fichtelgebirge and the Moldanubian Massif of the Bohemian Massif are crossed. Two northeast-southwest profiles illustrate the transition from the Franconian Forest or Fichtelgebirge to the southern German escarpment landscape via the fault of the Franconian Line.

In the 1800s, the spread of railroads enabled the growth and spread of the United States. Although slow by today’s standards, trains traveled more quickly than other forms of transportation available at the time. By train, it took roughly four days to reach San Francisco from Omaha, Nebraska. By contrast, it had taken covered wagons four to six months, and stagecoaches around a month. In addition to travel, railroads facilitated trade and economic growth. Prior to railroads, people relied on a system of roads and canals for transportation of goods and crops. But this system could be unreliable depending on road conditions, the weather, and many other factors. Trains brought products made in the factories of the East and Midwest to the rest of the country and carried farm produce and livestock to urban markets. The first railroad charter was granted to John Stevens in 1815, and several railroads were in service by 1830. Early rail development was haphazard, financed by individual investors and built without government oversight. Rail gauges, or the distance between rails, could be different depending on the company. This caused a lot of problems for connecting railroads, because only trains designed for that gauge could use those sections of track. Despite miles of track being built, people were generally still skeptical about the usefulness of railroads. In 1843, the Western Railroad of Massachusetts proved to Americans that trains could transport crops and other goods long distances at low costs. By 1861, there were 35,400 kilometers (22,000 miles) of track in the North and only 15,300 kilometers (9,500 miles) in the South. Troops and supplies could be transported quickly using trains. Many battles, like the Battle of Bull Run, were fought over control of Southern railway depots, and tracks were used to move both Confederate and Union soldiers to battles. After the Civil War, railway construction increased significantly. In 1862, Congress passed the Pacific Railway Act with the goal of building a transcontinental railroad. The first, built by the Central Pacific Railroad Company in the West and the Union Pacific in the Midwest, was completed in 1869. Following roughly the route previously taken by the Pony Express and the California Trail, the route was called the Overland Route. Construction was dangerous, as rail crews had to cross mountains, rivers, and other difficult terrain. For this work, the Central Pacific and Union Pacific relied mainly on immigrant labor, recruiting Chinese immigrants in the West and Irish immigrants in the Midwest. Formerly enslaved people and Mormons were also part of these crews. Between 10,000 and 15,000 Chinese workers completed an estimated 90 percent of work on the Central Pacific’s portion of track, facing racism, violence, and discrimination. Chinese workers were often paid less than white workers and were given the most undesirable and dangerous jobs. The Overland Route was one of the first land-grant railroads. To fund construction of such a long and expensive project, the U.S. government gave railroad companies millions of acres of land that they could sell for profit. Following this model, many more railroads were built, including four additional transcontinental railroads. These new railroads took southern and northern routes across the country. In addition to connecting existing cities on the West Coast to the rest of the country, the railroads also influenced where people settled. Trains made multiple stops to refuel, make repairs, and take on more food and water. In return, towns grew around these stops. More than 7,000 cities and towns west of the Missouri River started as Union Pacific depots and water stops. In 1890, the U.S. Bureau of the Census announced that the “Frontier was closed.” The railroads had played a large role in that milestone. This dataset was researched and built by Dr. Jeremy Atack, Professor Emeritus and Research Professor of Economics at Vanderbilt University. His procedure and sources, as well as downloadable files, are documented here.

Find local risk levels for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV) based on seasonal testing from June to October.

I. SNEP HRU Project Background The Southeast New England Program (SNEP) region consists of watersheds in Massachusetts and Rhode Island that primarily drain into Narragansett Bay, Buzzards Bay, or Nantucket Sound. It encompasses all or portions of 134 municipalities many of which are highly developed. The region faces multiple water quality issues with stormwater being previously identified a major contributor. These maps have been generated for all 134 Municipalities including 81 subwatersheds in the SNEP region to provide organizations and municipalities a way to understand where significant stormwater pollution may be originating. For organizations or municipalities with GIS capabilities the data that created these maps is available as well. II. What are HRUs? Hydrologic Response Units (HRUs) describe a landscape through unique combinations of land use and land cover (residential, commercial, forest, etc.), soil types (A, B, C, D), and additional characteristics such as slope, and impervious cover. These landscape characteristics, or HRUs, provide the building block to quantify stormwater pollutant loads (nitrogen, phosphorus, and total suspended solids (TSS)) originating from a given land area. The HRUs and nutrient pollutant loads in stormwater provides a baseline from which reduction targets can be created. III. How can HRUs be used? These maps and their underlying data can provide critical information to municipalities, watershed organizations, EPA, and others to assess stormwater pollutant loads in SNEP watersheds. EPA expects that this information will facilitate further understanding of the distribution of stormwater pollutant load source areas throughout the watersheds. This information serves to advance a broader understanding of stormwater impacts and potential management options by the public and direct stakeholders. Consistent HRUs may help municipalities implement MS4 permitting requirements and facilitate stormwater management strategies, such as land use conversion, stormwater Control Measure (SCM) siting, and targeting areas for conservation. HRU mapping can identify best locations for SCMs and can be utilized with additional stormwater planning tools (such as EPA’s Opti-Tool) to develop a cost-effective stormwater management plan. By providing a consistent HRU map for the SNEP region, practitioners can focus their efforts on implementation of SCM strategies rather than mapping their landscape. Hotspot mapping is a tool that integrates the HRU analysis and stormwater runoff pollutant load outputs to indicate areas where pollutant loads are highest and areas that stormwater controls may be best implemented. The HRUs and pollutant loads can be overlayed with parcel analysis to determine which parcels have high loads/areas of large impervious cover. The parcel data can help towns prioritize their efforts by determining the properties with highest potential to reduce pollutant loads through stormwater controls. Similarly, it can help determine which properties have large stormwater pollutant loads. IV. Other Resources HRUs That have been completed by EPA - Taunton River Watershed FDC Project and Tisbury, MA IC Disconnection Project The Cape Cod Commission developed HRUs for Barnstable County (CCC: Barnstable County HRUs). The UNH Stormwater Center developed parcel level hotspot mapping in New Hampshire for municipalities to prioritize where new BMPs should be placed (UNHSC: NH Hotspot Mapping).

Agnes Creek is located near the eastern outcrop margin of the Proterozoic Musgrave Province, which is composed predominantly of amphibolite to granulite facies meta-igneous and metasedimentary gneisses of the Birksgate Complex. Geochronological... Agnes Creek is located near the eastern outcrop margin of the Proterozoic Musgrave Province, which is composed predominantly of amphibolite to granulite facies meta-igneous and metasedimentary gneisses of the Birksgate Complex. Geochronological studies have shown that protolith ages for these rocks range in the eastern Musgrave Province between c. 1.7–1.5 Ga. The Birksgate Complex was intruded at c. 1.15 Ma by a number of granitoid bodies of the Pitjantjatjara Supersuite during the Musgravian Orogeny. These gneisses and granites were intruded by dykes of the c. 1080 Ma Alcurra Dolerite and the c. 800 Ma Amata Dolerite. Small serpentinite bodies exposed at the southern margin of De Rose Hill Station are possibly part of the c. 1080 Ma Giles Complex. These basement rocks are unconformably overlain in the southern part of Agnes Creek by Neoproterozoic sedimentary rocks of the Officer Basin, including the glaciogenic Chambers Bluff Tillite. The Moorilyanna Graben in the central part of Agnes Creek formed due to major tectonic movements along east-trending faults during the Petermann Orogeny between c. 550–500 Ma, and is filled with Cambrian siliciclastic sedimentary rocks (Moorilyanna Formation). Pervasive epidote and silica alteration of basement rocks along major east-trending faults is probably related to tectonic movements and fluid flow during the mid Paleozoic Alice Springs Orogeny. Mesozoic sedimentary rocks of the Eromanga Basin unconformably overlie Proterozoic basement rocks in the north-eastern part of Agnes Creek. Intense chemical weathering during the Neogene converted exposed basement rocks into clay-rich saprolite and led to the formation of extensive silcrete and ferricrete. Cenozoic fluvial and aeolian sediments cover large parts of Agnes Creek. Work on the current Agnes Creek map sheet began in 2012 with extensive field mapping. A significant amount of petrographic, geochemical, isotopic and geochronological data were also collected and analysed to complement field observations.

The deep sea sedimentary record is an archive of the pre-glacial to glacial development of Antarctica and changes in climate, tectonics and ocean circulation. Identification of the pre-glacial, transitional and full glacial components in the sedimentary record is necessary for ice sheet reconstruction and to build circum-Antarctic sediment thickness grids for past topography and bathymetry reconstructions, which constrain paleoclimate models. A ~3300 km long Weddell Sea to Scotia Sea transect consisting of multichannel seismic reflection data from various organisations, were used to interpret new horizons to define the initial basin-wide seismostratigraphy and to identify the pre-glacial to glacial components. We mapped seven main units of which three are in the inferred Cretaceous-Paleocene pre-glacial regime, one in the Eocene-Oligocene transitional regime and three units in the Miocene-Pleistocene full glacial climate regime. Sparse borehole data from ODP leg 113 and SHALDRIL constrain the ages of the upper three units. Compiled seafloor spreading magnetic anomalies constrain the basement ages and the hypothetical age model. In many cases, the new horizons and stratigraphy contradict the interpretations in local studies. Each seismic sedimentary unit and its associated base horizon are continuous and traceable for the entire transect length, but reflect a lateral change in age whilst representing the same deposition process. The up to 1240 m thick pre-glacial seismic units form a mound in the central Weddell Sea basin and, in conjunction with the eroded flank geometry, support the interpretation of a Cretaceous proto-Weddell Gyre. The base reflector of the transitional seismic unit, which marks the initial ice sheet advances to the outer shelf, has a lateral model age of 26.6-15.5 Ma from southeast to northwest. The Pliocene-Pleistocene glacial deposits reveals lower sedimentations rates, indicating a reduced sediment supply. Sedimentation rates for the pre-glacial, transitional and full glacial components are highest around the Antarctic Peninsula, indicating higher erosion and sediment supply of a younger basement. We interpret an Eocene East Antarctic Ice Sheet expansion, Oligocene grounding of the West Antarctic Ice Sheet and Early Miocene grounding of the Antarctic Peninsula Ice Sheet.

April 2025

This geodatabase contains all the geologic map information for the Geologic Map of the San Juan caldera cluster, southwestern Colorado and is part of U.S. Geological Survey Geologic Investigations Map Series I-2799. The San Juan Mountains are the largest erosional remnant of a composite volcanic field that covered much of the southern Rocky Mountains in middle Tertiary time. The San Juan field consists mainly of intermediate-composition lavas and breccias, erupted about 35-30 Ma from scattered central volcanoes (Conejos Formation) and overlain by voluminous ash-flow sheets erupted from caldera sources. In the central San Juan Mountains, eruption of at least 8,800 km3 of dacitic-rhyolitic magma as nine major ash flow sheets (individually 150-5,000 km3) was accompanied by recurrent caldera subsidence between 28.3 Ma and about 26.5 Ma. Voluminous andesitic-dacitic lavas and breccias were erupted from central volcanoes prior to the ash-flow eruptions, and similar lava eruptions continued within and adjacent to the calderas during the period of more silicic explosive volcanism. Exposed calderas vary in size from 10 to 75 km in maximum dimension, the largest calderas being associated with the most voluminous eruptions.

The following dashboards provide data on contagious respiratory viruses, including acute respiratory diseases, COVID-19, influenza (flu), and respiratory syncytial virus (RSV) in Massachusetts. The data presented here can help track trends in respiratory disease and vaccination activity across Massachusetts.

The MAITLAND Special 1:250,000 scale geological map covers the greater part of South Australia's Yorke Peninsula. The rocks in the map area comprise deformed Palaeoproterozoic and early Mesoproterozoic basement of the south-eastern Gawler Craton,... The MAITLAND Special 1:250,000 scale geological map covers the greater part of South Australia's Yorke Peninsula. The rocks in the map area comprise deformed Palaeoproterozoic and early Mesoproterozoic basement of the south-eastern Gawler Craton, and undeformed Neoproterozoic to Quaternary sediments. More than 90% of the land surface in the map area is covered by Quaternary sand dunes, calcrete, aeolianite and soil. The oldest rocks on Yorke Peninsula belong to the middle Palaeoproterozoic Corny Point Paragneiss (~1920-1845 Ma), which has a Hutchison Group equivalent protolith and was metamorphosed at ~1845 Ma. Several felsic and mafic plutonic suites, principally Gleesons Landing Granite, intrude the paragneiss on the southern part of the peninsula. The early phases of this I-type granite could be as old as ~1855 Ma, and are intruded by megacrystic augen orthogneiss (~1850 Ma). The Gleesons Landing Granite is intruded by the deformed Royston Granite (~1849.5 Ma) and mafic dykes (Tournefort Metadolerite). The late Palaeoproterozoic Wallaroo Group (1770-1740 Ma) comprises a succession of metasediments and volcanics, and in the northern part of the map area hosts the Moonta - Wallaroo Cu-Au deposits. The Wallaroo Group is considered to have been deformed by the Kimban Orogeny (in the restricted sense of Schwarz, 2003) during 1730-1700 Ma, and was later intruded by early Mesoproterozoic Tickera Granite (1598-1586 Ma), Curramulka Gabbronorite (1589 Ma) and Arthurton Granite (1582 Ma). Neoproterozoic sediments are known to be present on MAITLAND only from drillhole intersections made in the north-eastern part of the map area, and were deposited along the Torrens Hinge Zone marginal to the Adelaide Geosyncline. The units intersected include Rhynie Sandstone, Sturt Tillite and Tapley Hill Formation. The Cambrian Stansbury Basin on Yorke Peninsula is interpreted to have formed on a rifted continental platform on the eastern Gawler Craton; sediments within it up to 2000 m thick are interpreted from seismic surveys. Generally, the Cambrian succession contains three sequence sets and records two local marine transgression and regression cycles. The Cambrian sediments have petroleum potential in the region. Permian diamictite crops out on southern Yorke Peninsula and is widely encountered in drillholes. The diamictite (Cape Jervis Formation) was deposited in glacio-lacustrine, glaciofluvial and restricted marine environments. Tertiary sediments are exposed in the coastal cliffs of the eastern side of Yorke Peninsula and consist of siliciclastics with minor carbonates. Deposition of the overlying Quaternary succession was probably controlled by glacial-eustatic sea level oscillations, resulting in periodic submarine deposition. Several marine transgressions, evidenced by limestone beds of the littoral-pelagic Point Ellen Formation (~1.2 Ma), tidal channel deposits at the base of the Bridgewater Formation (<0.78 Ma), fossiliferous Glanville Formation (~0.125 Ma) and Posidonia-bearing beds of the St Kilda Formation (~6000 years), are recognised. The tectonic development of Yorke Peninsula has been relatively complicated, particularly with respect to the formation of the basement rocks, and interpretation is made especially difficult due to their poor surface exposure. Generally in the region, six major primary rock-forming events can be recognised, relating to deposition of the middle Palaeoproterozoic (1920-1845 Ma Corny Point Paragneiss), the late Palaeoproterozoic (1770-1740 Ma Wallaroo Group), and the Neoproterozoic (~770-700 Ma), Cambrian (~540- 500 Ma), Permian and Tertiary sediments. In terms of regional structural geology, seven rock deformational or shear-faulting events (D1-D7) are recognised in this study.

The Six Mile Hill 1:75 000 Map Sheet was produced as part of a mapping program integrated into the Mineral Systems Drilling Program (MSDP) along the southern margin of the Gawler Ranges. The objective of the mapping program was to provide a... The Six Mile Hill 1:75 000 Map Sheet was produced as part of a mapping program integrated into the Mineral Systems Drilling Program (MSDP) along the southern margin of the Gawler Ranges. The objective of the mapping program was to provide a regional geological context in which the stratigraphy, alteration and mineralisation of rocks revealed by the MSDP drilling could be interpreted, and comprised detailed basement, structural and regolith mapping. This report comprises the Explanatory Notes to the Six Mile Hill Map Sheet, part of the Mineral Systems Drilling Program Special Map Series. Six Mile Hill spans a number of geological provinces, including the Mesoarchaean-Mesoproterozoic Gawler Craton, the Mesoproterozoic Cariewerloo Basin and the Neoproterozoic Stuart Shelf, as well as preserving a protracted history of deposition in the Cenozoic. The earliest history of the area is recorded by a phase of basin development in the late Palaeoproterozoic, comprising the deposition of the Broadview Schist, and emplacement of the Wire Dam Dolerite and Tip Top Granite, accompanied by solid-state deformation between c. 1790 and 1775 Ma. Further sedimentation occurred at c. 1755 Ma, comprising deposition of the Moonabie and Wandearah formations. This was followed by intrusion of the Moola Suite at c. 1745 Ma, and basin inversion during the Kimban Orogeny (c. 1740–1690 Ma), which comprised low temperature fabric development and the formation of mylonites and thrust faults during west-southwest-directed shortening. Open folding of the Moonabie Formation during northeast-directed shortening may have occurred during the Kimban Orogeny or early during the Kararan Orogeny (c. 1610–1590 Ma). This was followed by eruption of extrusive and pyroclastic felsic volcanics and subaerial and subaqueous basaltic lavas of the Gawler Range Volcanics during the early Mesoproterozoic (c. 1590 Ma). The Gawler Craton was overlain by fluvial red beds of the Pandurra Formation at c. 1420 Ma, and was subsequently subject to weathering and erosion until the Neoproterozoic. Deposition of sediments on the Stuart Shelf commenced at c. 825 Ma with fluvial sediments of the Backy Point Formation interlayered with subaerial basaltic lavas of the Beda Basalt, and intrusion of the Gairdner Dolerite in the Gawler Craton. The Stuart Shelf was subject to exposure and erosion until c. 645 Ma when there was marine transgression and deposition of the Tapley Hill Formation. This was followed by localised deposition of fluvio-deltaic to shallow marine facies of the Upalinna and Yerelina subgroups, including the Whyalla Sandstone, and then post-glacial transgression and deposition of the Tent Hill Formation after c. 635 Ma. Six Mile Hill was subject to weathering and erosion during the Palaeozoic and Mesozoic, after which it records deep weathering, silicification and ferruginisation, as well as the deposition of colluvial, alluvial and aeolian deposits during the Cenozoic, and neotectonic faulting.

This spring, MassWildlife stocked brook, brown, rainbow, and tiger trout in over 450 lakes, ponds, rivers, and streams in 264 towns across Massachusetts!