This data collection is associated with the publications: Merdith, A. S., Landgrebe, T. C. W., Dutkiewicz, A., & Müller, R. D. (2013). Towards a predictive model for opal exploration using a spatio-temporal data mining approach. Australian Journal of Earth Sciences, 60(2), 217-229. doi: 10.1080/08120099.2012.754793

and

Landgrebe, T. C. W., Merdith, A., Dutkiewicz, A., & Müller, R. D. (2013). Relationships between palaeogeography and opal occurrence in Australia: A data-mining approach. Computers & Geosciences, 56(0), 76-82. doi: 10.1016/j.cageo.2013.02.002

Publication Abstract - Merdith et al. (2013)

Opal is Australia's national gemstone, however most significant opal discoveries were made in the early 1900's - more than 100 years ago - until recently. Currently there is no formal exploration model for opal, meaning there are no widely accepted concepts or methodologies available to suggest where new opal fields may be found. As a consequence opal mining in Australia is a cottage industry with the majority of opal exploration focused around old opal fields. The EarthByte Group has developed a new opal exploration methodology for the Great Artesian Basin. The work is based on the concept of applying “big data mining” approaches to data sets relevant for identifying regions that are prospective for opal. The group combined a multitude of geological and geophysical data sets that were jointly analysed to establish associations between particular features in the data with known opal mining sites. A “training set” of known opal localities (1036 opal mines) was assembled, using those localities, which were featured in published reports and on maps. The data used include rock types, soil type, regolith type, topography, radiometric data and a stack of digital palaeogeographic maps. The different data layers were analysed via spatio-temporal data mining combining the GPlates PaleoGIS software (www.gplates.org) with the Orange data mining software (orange.biolab.si) to produce the first opal prospectivity map for the Great Artesian Basin. One of the main results of the study is that the geological conditions favourable for opal were found to be related to a particular sequence of surface environments over geological time. These conditions involved alternating shallow seas and river systems followed by uplift and erosion. The approach reduces the entire area of the Great Artesian Basin to a mere 6% that is deemed to be prospective for opal exploration. The work is described in two companion papers in the Australian Journal of Earth Sciences and Computers and Geosciences.

Publication Abstract - Landgrebe et al. (2013)

Age-coded multi-layered geological datasets are becoming increasingly prevalent with the surge in open-access geodata, yet there are few methodologies for extracting geological information and knowledge from these data. We present a novel methodology, based on the open-source GPlates software in which age-coded digital palaeogeographic maps are used to “data-mine” spatio-temporal patterns related to the occurrence of Australian opal. Our aim is to test the concept that only a particular sequence of depositional/erosional environments may lead to conditions suitable for the formation of gem quality sedimentary opal. Time-varying geographic environment properties are extracted from a digital palaeogeographic dataset of the eastern Australian Great Artesian Basin (GAB) at 1036 opal localities. We obtain a total of 52 independent ordinal sequences sampling 19 time slices from the Early Cretaceous to the present-day. We find that 95% of the known opal deposits are tied to only 27 sequences all comprising fluvial and shallow marine depositional sequences followed by a prolonged phase of erosion. We then map the total area of the GAB that matches these 27 opal-specific sequences, resulting in an opal-prospective region of only about 10% of the total area of the basin. The key patterns underlying this association involve only a small number of key environmental transitions. We demonstrate that these key associations are generally absent at arbitrary locations in the basin. This new methodology allows for the simplification of a complex time-varying geological dataset into a single map view, enabling straightforward application for opal exploration and for future co-assessment with other datasets/geological criteria. This approach may help unravel the poorly understood opal formation process using an empirical spatio-temporal data-mining methodology and readily available datasets to aid hypothesis testing.

Authors and Institutions

Andrew Merdith - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia. ORCID: 0000-0002-7564-8149

Thomas Landgrebe - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia

Adriana Dutkiewicz - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia

R. Dietmar Müller - EarthByte Research Group, School of Geosciences, The University of Sydney, Australia. ORCID: 0000-0002-3334-5764

Overview of Resources Contained

This collection contains geological data from Australia used for data mining in the publications Merdith et al. (2013) and Landgrebe et al. (2013). The resulting maps of opal prospectivity are also included.

List of Resources

Note: For details on the files included in this data collection, see “Description_of_Resources.txt”.

Note: For information on file formats and what programs to use to interact with various file formats, see “File_Formats_and_Recommended_Programs.txt”.

• Map of Barfield region, Australia (.jpg, 270 KB)
• Map overviewing the Great Artesian basins and main opal mining camps (.png, 82 KB)
• Maps showing opal prospectivity data mining results for different geological datasets (.tif, 23.1 MB)
• Map of opal prospectivity from palaeogeography data mining (.pdf, 2.6 MB)
• Raster of palaeogeography target regions for viewing in Google Earth (.jpg, 418 KB)
• Opal mine locations (.gpml, .txt, .kmz, .shp, total 15.6 MB)
• Map of opal prospectivity from all data mining results as a Google Earth overlay (.kmz, 12 KB)
• Map of probability of opal occurrence in prospective regions from all data mining results (.tif, 5.9 MB)
• Paleogeography of Australia (.gpml, .txt, .shp, total 114.2 MB)
• Radiometric data showing potassium concentration contrasts (.tif, .kmz, total 311.3 MB)
• Regolith data (.gpml, .txt, .kml, .shp, total 7.1 MB)
• Soil type data (.gpml, .txt, .kml, .shp, total 7.1 MB)

For more information on this data collection, and links to other datasets from the EarthByte Research Group please visit EarthByte

For more information about using GPlates, including tutorials and a user manual please visit GPlates or EarthByte

URL: https://geoscience.data.qld.gov.au/dataset/mr001857

Queensland Opal - Opalton and Eromanga-Eulo Areas Map 2 Edition 4 The Queensland Opal two Map Sheet and Commentary publication was revised in 1993, it is a guide to opal locations and prospective areas, and shows the access to various fields and mines. These fourth edition maps have a simplified geological background and updates have been made to the data on mine locations and their working status, and to Mining District boundaries. The emphasis on geology is intended to indicate the more prospective ground of the deeply weathered sections of the Winton Formation where opal is more likely to occur. As well, it is a map of the outcropping rocks of the country, and can be used whilst travelling the highways, minor roads, and bush tracks, not only to indicate good opal country, but also to reflect the landforms of the region. This publication is a joint development of the Department of Minerals and Energy, the Winton Shire Council and the Department of Business, Industry and Regional Development. The map product is available to all government agencies, industry and the public for reference.

Queensland Opal - Opalton and Eromanga-Eulo Areas Map 2 of 2 Edition 4 plus Commentary booklet. Author: Blight, RKJ, Gatehouse, NC, Wegner, M, McShea, R, Hill, R, Stewart, P.

URL: https://geoscience.data.qld.gov.au/dataset/mr001856

Queensland Opal - Western Queensland Map 1 Edition 4 The Queensland Opal two Map Sheet and Commentary publication was revised in 1993, it is a guide to opal locations and prospective areas, and shows the access to various fields and mines. These fourth edition maps have a simplified geological background and updates have been made to the data on mine locations and their working status, and to Mining District boundaries. The emphasis on geology is intended to indicate the more prospective ground of the deeply weathered sections of the Winton Formation where opal is more likely to occur. As well, it is a map of the outcropping rocks of the country, and can be used whilst travelling the highways, minor roads, and bush tracks, not only to indicate good opal country, but also to reflect the landforms of the region. This publication is a joint development of the Department of Minerals and Energy, the Winton Shire Council and the Department of Business, Industry and Regional Development. The map product is available to all government agencies, industry and the public for reference.

Queensland Opal - Western Queensland Map 1 of 2 Edition 4 plus Commentary booklet. Author: Blight, RKJ, Gatehouse, NC, Wegner, M, McShea, R, Hill, R, Stewart, P.

A polygon Arcview shapefile of northern Nevada cryptocrystalline occurrences derived from Nevada rockhound guides and converted to a coverage.

Location of all current mineral exploration licence applications issued under the Mining Act 1971. Assessment and comment is sought on applications from numerous sources before granting a licence.

Available format: ESRI Shape, MAPINFO Tab, Google Earth KMZ and WMS/WFS.

Instructions: From SARIG webservice, Map Layers, click on 'Mineral Tenements', 'Mineral Exploration Tenements', 'Applications, Exploration Licence (Mineral/Opal)'.

For information on how to download dataset visit http://www.minerals.dmitre.sa.gov.au/sarighelp/map_layers#L5

Link to the ScienceBase Item Summary page for the item described by this metadata record. Service Protocol: Link to the ScienceBase Item Summary page for the item described by this metadata record. Application Profile: Web Browser. Link Function: information

URL: https://geoscience.data.qld.gov.au/dataset/mr009287

The QUEENSLAND OPAL FIELDS WESTERN QUEENSLAND Gemfields map was published in 1977 at 1:1 000 000 as part of the MINES PUBLICATION series to administer permit and permit related spatial information. The map was maintained internally as a provisional office chart and is located within the (7140, 7141, 7142, 7143, 7144, 7145, 7146, 7147, 7148, 7149, 7150, 7151, 7152, 7153, 7154, 7155, 7240, 7241, 7242, 7243, 7244, 7245, 7246, 7247, 7248, 7249, 7250, 7251, 7252, 7253, 7254, 7255, 7340, 7341, 7342, 7343, 7344, 7345, 7346, 7347, 7348, 7349, 7350, 7351, 7352, 7353, 7354, 7355, 7440, 7441, 7442, 7443, 7444, 7445, 7446, 7447, 7448, 7449, 7450, 7451, 7452, 7453, 7454, 7455, 7540, 7541, 7542, 7543, 7544, 7545, 7546, 7547, 7548, 7549, 7550, 7551, 7552, 7553, 7554, 7555, 7640, 7641, 7642, 7643, 7644, 7645, 7646, 7647, 7648, 7649, 7650, 7651, 7652, 7653, 7654, 7655, 7740, 7741, 7742, 7743, 7744, 7745, 7746, 7747, 7748, 7749, 7750, 7751, 7752, 7753, 7754, 7755, 7840, 7841, 7842, 7843, 7844, 7845, 7846, 7847, 7848, 7849, 7850, 7851, 7852, 7853, 7854, 7855, 7940, 7941, 7942, 7943, 7944, 7945, 7946, 7947, 7948, 7949, 7950, 7951, 7952, 7953, 7954, 7955, 8040, 8041, 8042, 8043, 8044, 8045, 8046, 8047, 8048, 8049, 8050, 8051, 8052, 8053, 8054, 8055) 1:100 000 map areas.
The map product is available to all government agencies, industry and the public for reference.
Title and Image reference number is QUEENSLAND OPAL FIELDS WESTERN QUEENSLAND_7268.

Revised 1984, Western Queensland

1. Band ratio: B11/(B10+B12) Blue is low quartz content Red is high quartz content Geoscience Applications: Use in combination with Silica index to more accurately map "crystalline" quartz rather than poorly ordered silica (e.g. opal), feldspars and compacted clays.

Link to the ScienceBase Item Summary page for the item described by this metadata record. Service Protocol: Link to the ScienceBase Item Summary page for the item described by this metadata record. Application Profile: Web Browser. Link Function: information

URL: https://geoscience.data.qld.gov.au/dataset/mr010890

The QUEENSLAND OPAL FIELDS Mine map was published in 1977 at 1:500 000, and charted by the Mines District Office to administer permit and permit related spatial information. The map was maintained internally as a provisional office chart and is located within the () 1:100 000 map area.
The map product is available to all government agencies, industry and the public for reference.
Title and Image reference number is QUEENSLAND OPAL FIELDS_0156.
Hard copy can be found in Cabinet PU78-45 Drawer 5.

This report was prepared by the Mineral Economics Section. Part 1 deals with the production of opal and includes sections on the history and present operations in the industry, production and overseas trade statistics, and the types of mining tenures at present available to opal miners. The fields at present being worked are described and the factors which affect production are discussed. Part 2 deals with the marketing of opal and includes sections on the cutting and preparation of stone, markets at home and abroad, and the various factors affecting trade. A number of proposals for improving trade and trading conditions generally are discussed, and the report concludes with a list of references in literature, two graphs showing the value of opal produced in each State and the whole of Australia, from 1890 to 1947, and a map of Australia showing localities mentioned in the text.

Understanding the evolution of Arctic polar climate from the protracted warmth of the middle Pliocene into the earliest glacial cycles in the Northern Hemisphere has been hindered by the lack of continuous, highly resolved Arctic time series. Evidence from Lake El'gygytgyn, NE Arctic Russia, shows that 3.6-3.4 million years ago, summer temperatures were ~8°C warmer than today when pCO2 was ~400 ppm. Multiproxy evidence suggests extreme warmth and polar amplification during the middle Pliocene, sudden stepped cooling events during the Pliocene-Pleistocene transition, and warmer than present Arctic summers until ~2.2 Ma, after the onset of Northern Hemispheric glaciation. Our data are consistent with sea-level records and other proxies indicating that Arctic cooling was insufficient to support large-scale ice sheets until the early Pleistocene.

This submission includes composite risk segment models in raster format for permeability, heat of the earth, and MT, as well as the final PFA model of geothermal exploration risk in Southwestern Utah, USA. Additionally, this submission has data regarding hydrothermally altered areas, and opal sinter deposits in the study area. All of this information lends to the understanding and exploration for hidden geothermal systems in the area.

One mosaic of the map sheet: 1. Géomorphologie. Scale of 1:100 000. Date of publication: 1981.

There is no description available.

The map sheet: 1. Carte gravimétrique de Haute-Volta. Scale of 1:5 000 000 to 1:1 000 000. Date of publication: 1962.

1. Band ratio: (B6+B8)/B7 Blue is low content, Red is high content (potentially includes: chlorite, epidote, jarosite, nontronite, gibbsite, gypsum, opal-chalcedony) Useful for mapping: (1) jarosite (acid conditions) - in combination with ferric oxide content (high); (2) gypsum/gibbsite - in combination with ferric oxide content (low); (3) magnesite - in combination with ferric oxide content (low) and MgOH content (moderate-high) (4) chlorite (e.g. propyllitic alteration) - in combination with Ferrous in MgOH (high); and (5) epidote (calc-silicate alteration) - in combination with Ferrous in MgOH (low).

There is no description available.

This dataset is about: Stable oxygen isotope ratios in opal and seawater from various locations. Please consult parent dataset @ https://doi.org/10.1594/PANGAEA.789256 for more information.

URL: https://geoscience.data.qld.gov.au/dataset/mr009385

The YOWAH OPAL FIELD Mine map was published in 2012 at 1:5 000 as part of the MINES PUBLICATION series to administer permit and permit related spatial information. The map was maintained internally as a provisional office chart and is located within the Dundoo (7842) 1:100 000 map area. The map product is available to all government agencies, industry and the public for reference. Title and Image reference number is YOWAH OPAL FIELD_9797.

Drawn by Mapping and Survey Section 7th March 2012