{"help": "https://data.gov.au/data/en/api/3/action/help_show?name=package_show", "success": true, "result": {"archived": false, "author_email": null, "contact_point": "clientservices@ga.gov.au", "creator_user_id": "c2fbbe4a-4ba0-4945-808b-67454605a4cf", "duplicate_score": 1, "geospatial_topic": [], "id": "f4731898-b0ba-43cb-896f-f02091d7eaf5", "isopen": false, "language": "eng", "license_id": "notspecified", "license_title": "notspecified", "maintainer": null, "maintainer_email": null, "metadata_created": "2025-10-16T13:24:27.872244", "metadata_modified": "2025-10-16T13:24:27.872251", "name": "characterization-of-uranium-redox-state-in-organic-rich-marine-sediments-of-the-cretaceous-tool", "notes": "Throughout geological history, marine organic-rich shales show variable but appreciable enrichment in uranium (U),  500 ppm. Here we report the results of high-energy resolution fluorescence detection (HERFD) x-ray absorption spectroscopy at U L3 and M4 edges to characterize U speciation in marine sediments.\n\nWe characterised U oxidation state in samples from the Cretaceous Toolebuc Formation of the Eromanga Basin, Australia. Nine samples were carbonaceous shales with high total organic carbon (TOC) content of 5.9 to 13.4 wt % and with low maturity organic matter. Two samples of coquinite were selected for comparison (TOC 0.3 and 2.4 wt %).\n\nOur results suggest that a significant proportion of U in marine black shales (~20 to 30%) exists as U(VI) (Figures 1-2), despite the extremely reducing (anoxic to euxinic) conditions during sediment precipitation and diagenesis. Within individual samples, spot analyses indicate variation in the estimated oxidation state within a range of ~20% of U(VI). Uranium is unevenly distributed at mm to nanoscale. Nanoscale secondary ion mass spectrometry (NanoSIMS) reveals different associations that often coexist in single samples; nano-particulate uranium is associated with organic matter matrix or sulphide minerals, whereas phosphate minerals display diffuse uranium enrichment. The coquinite has a higher proportion of U(VI), consistent with the dysoxic depositional environment (Boreham and Powell, 1987).\n\nThe unexpectedly enhanced proportion of U(VI) relative to U(IV) within marine organic-rich shales implies that U might not be immediately fixed by reduction processes during sedimentation, but adsorbed by accumulating organic matter, at least in part as U(VI). This is consistent with the behaviour of uranium reported within the water column of the anoxic Black Sea (Anderson, 1989), experiments on U(VI) sorption by organic matter (e.g., Bhat et al., 2008), and previously documented redox state of U from continental organic-rich Eocene (56-34 Ma) sediments of paleochannel and lacustrine origin (Cumberland et al., 2018).\n\nThe results are significant for improving hydrocarbon exploration in known fields (covering the gap to a carbon-free economy without development of new greenfield oil provinces); economic geology (uranium, base-metal, and critical-metal deposits); and environmental management (evaluating potential mobilization of U by groundwaters).\n\nThis Abstract was submitted and presented to the 2023 Goldschmidt Conference Lyon, France (https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi)", "num_resources": 2, "num_tags": 8, "organization": {"id": "91f054ec-d0c3-4d42-a89a-5daa2c7a6818", "name": "geoscience-australia-data", "title": "Geoscience Australia Data", "type": "organization", "description": "Harvester for Geoscience Australia Data", "image_url": "", "created": "2025-06-23T12:29:08.024111", "is_organization": true, "approval_status": "approved", "state": "active"}, "original_harvest_source": {"site_url": "https://ecat.ga.gov.au", "href": "https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/characterization-of-uranium-redox-state-in-organic-rich-marine-sediments-of-the-cretaceous-tool", "title": "Geoscience Australia"}, "owner_org": "91f054ec-d0c3-4d42-a89a-5daa2c7a6818", "private": false, "promotion_level": "0", "spatial": "{\"type\": \"Polygon\", \"coordinates\": [[[112.0, -44.0], [154.0, -44.0], [154.0, -9.0], [112.0, -9.0], [112.0, -44.0]]]}", "spatial_coverage": "{\"type\": \"Polygon\", \"coordinates\": [[[112.0, -44.0], [154.0, -44.0], [154.0, -9.0], [112.0, -9.0], [112.0, -44.0]]]}", "state": "active", "temporal_coverage_from": "2023-09-19 21:54:58", "title": "Characterization of uranium redox state in organic-rich marine sediments of the Cretaceous Toolebuc Formation, Australia", "type": "dataset", "unpublished": false, "url": null, "version": null, "resources": [{"cache_last_updated": null, "cache_url": null, "created": "2025-10-16T13:24:27.873767", "datastore_active": false, "datastore_contains_all_records_of_source_file": false, "description": "Link to Conference Page", "format": "HTML", "hash": "", "id": "1af3fc9b-a113-462b-ae2e-1eb310c82170", "last_modified": null, "metadata_modified": "2025-10-16T13:24:27.862671", "mimetype": null, "mimetype_inner": null, "name": "Link to Conference Page", "package_id": "f4731898-b0ba-43cb-896f-f02091d7eaf5", "position": 0, "resource_locator_function": "", "resource_locator_protocol": "WWW:LINK-1.0-http--link", "resource_type": null, "size": null, "state": "active", "url": "https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi", "url_type": null, "zip_extract": false}, {"cache_last_updated": null, "cache_url": null, "created": "2025-10-16T13:24:27.873771", "datastore_active": false, "datastore_contains_all_records_of_source_file": false, "description": "Link to Conference Paper", "format": "HTML", "hash": "", "id": "e14d51ea-7b97-4c70-851b-7927a0f19116", "last_modified": null, "metadata_modified": "2025-10-16T13:24:27.862865", "mimetype": null, "mimetype_inner": null, "name": "Link to Conference Paper", "package_id": "f4731898-b0ba-43cb-896f-f02091d7eaf5", "position": 1, "resource_locator_function": "", "resource_locator_protocol": "WWW:LINK-1.0-http--link", "resource_type": null, "size": null, "state": "active", "url": "https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi/Paper/19977", "url_type": null, "zip_extract": false}], "tags": [{"display_name": "EFTF \u2013 Exploring for the Future", "id": "909d5c1c-3ed4-40c5-abcd-3fe164de1b08", "name": "EFTF \u2013 Exploring for the Future", "state": "active", "vocabulary_id": null}, {"display_name": "Geochemistry", "id": "e3abf967-e82d-46fa-b59a-b7e0e79e7c52", "name": "Geochemistry", "state": "active", "vocabulary_id": null}, {"display_name": "Geochemistry not elsewhere classified", "id": "17af571d-b56d-4480-9853-2b80fa395513", "name": "Geochemistry not elsewhere classified", "state": "active", "vocabulary_id": null}, {"display_name": "Inorganic Geochemistry", "id": "2060b13a-383f-41e4-840a-e19a66321265", "name": "Inorganic Geochemistry", "state": "active", "vocabulary_id": null}, {"display_name": "Organic Geochemistry", "id": "352c8196-76ed-4a82-bc33-3bc6fb079149", "name": "Organic Geochemistry", "state": "active", "vocabulary_id": null}, {"display_name": "Published_External", "id": "5178775c-8044-4b7f-881f-5428a4e2d925", "name": "Published_External", "state": "active", "vocabulary_id": null}, {"display_name": "Unconventional Hydrocarbons", "id": "9e7f22d3-d04d-4c4b-ac86-611ff2a91511", "name": "Unconventional Hydrocarbons", "state": "active", "vocabulary_id": null}, {"display_name": "trace elements", "id": "ec0a7acf-c353-4802-9247-a18ed653be17", "name": "trace elements", "state": "active", "vocabulary_id": null}], "groups": [], "relationships_as_subject": [], "relationships_as_object": [], "extras": [{"key": "harvest_object_id", "value": "31d6935a-df7b-48cd-9082-fdf5ac50282a"}, {"key": "harvest_source_id", "value": "00080910-39e7-408f-882c-e6e1eb6baadb"}, {"key": "harvest_source_title", "value": "Geoscience Australia"}]}}