Authors / CoAuthors
de Caritat, P. | Dosseto, A. | Dux, F.
Abstract
<div>Strontium isotopes (87Sr/86Sr) are useful in the earth sciences (e.g. recognising geological provinces, studying geological processes) as well in archaeological (e.g. informing on past human migrations), palaeontological/ecological (e.g. investigating extinct and extant taxa’s dietary range and migrations) and forensic (e.g. validating the origin of drinks and foodstuffs) sciences. Recently, Geoscience Australia and the University of Wollongong have teamed up to determine 87Sr/86Sr ratios in fluvial sediments selected mostly from the low-density National Geochemical Survey of Australia (www.ga.gov.au/ngsa), with a few additional Northern Australia Geochemical Survey infill samples. The present study targeted the northern parts of Western Australia, the Northern Territory and Queensland in Australia, north of 21.5 °S. The samples were taken mostly from a depth of ~60-80 cm depth in floodplain deposits at or near the outlet of large catchments (drainage basins). A coarse grain-size fraction (<2 mm) was air-dried, sieved, milled then digested (hydrofluoric acid + nitric acid followed by aqua regia) to release total strontium. Preliminary results demonstrate a wide range of strontium isotopic values (0.7048 < 87Sr/86Sr < 1.0330) over the survey area, reflecting a large diversity of source rock lithologies, geological processes and bedrock ages. Spatial distribution of 87Sr/86Sr shows coherent (multi-point anomalies and smooth gradients), large-scale (>100 km) patterns that appears to be consistent, in many places, with surface geology, regolith/soil type and/or nearby outcropping bedrock. For instance, the extensive black clay soils of the Barkly Tableland define a >500 km-long northwest-southeast-trending low anomaly (87Sr/86Sr < 0.7182). Where carbonate or mafic igneous rocks dominate, a low to moderate strontium isotope signature is observed. In proximity to the outcropping Proterozoic metamorphic provinces of the Tennant, McArthur, Murphy and Mount Isa geological regions, conversely, high 87Sr/86Sr values (> 0.7655) are observed. A potential link between mineralisation and elevated 87Sr/86Sr values in these regions needs to be investigated in greater detail. Our results to-date indicate that incorporating soil/regolith strontium isotopes in regional, exploratory geoscience investigations can help identify basement rock types under (shallow) cover, constrain surface processes (e.g. weathering, dispersion), and, potentially, recognise components of mineral systems. Furthermore, the resulting strontium isoscape and model derived therefrom can also be utilised in archaeological, paleontological and ecological studies that aim to investigate past and modern animal (including humans) dietary habits and migrations. The new spatial dataset is publicly available through the Geoscience Australia portal https://portal.ga.gov.au/.</div>
Product Type
dataset
eCat Id
147473
Contact for the resource
Resource provider
Point of contact
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Point of contact
- Contact instructions
- MEG
Digital Object Identifier
Keywords
- ( Project )
-
- EFTF – Exploring for the Future
- ( Project )
-
- National Database of Archived Samples
- ( Project )
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- Isotopic Atlas of Australia
- ( Project )
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- Barkly-Isa-Georgetown
- ( Project )
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- EFTF
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- Mineral exploration
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- Sr isotopes
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- regolith
- theme.ANZRC Fields of Research.rdf
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- Soil chemistry and soil carbon sequestration (excl. carbon sequestration science)Isotope geochemistryExploration geochemistry
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- Published_External
Publication Date
2022-12-14T03:05:17
Creation Date
2022-11-30T09:00:00
Security Constraints
Legal Constraints
Use - license otherRestrictions
Status
completed
Purpose
Deliver isotopic data to EFTF Stakeholders
Maintenance Information
asNeeded
Topic Category
geoscientificInformation
Series Information
Lineage
<div>National Geochemical Survey of Australia (http://dx.doi.org/10.11636/Record.2011.020)</div><div>Northern Australia Geochemical Survey (http://dx.doi.org/10.11636/Record.2019.002)</div>
Parent Information
Extents
[-21.5, -11, 116, 149]
Reference System
GDA94 / geographic 2D (EPSG: 4283)
Spatial Resolution
Service Information
Associations
Association Type - informed
A strontium isoscape of inland southeastern Australia
eCat Identifier - 146397,
UUID - 004c6972-4d53-4b8f-ba35-2d2469d644e9
Association Type - wasDerivedFrom
National Geochemical Survey of Australia: The Geochemical Atlas of Australia
eCat Identifier - 71973,
UUID - a4a1ac2e-0a2c-653b-e044-00144fdd4fa6
Association Type - wasDerivedFrom
Northern Australia Geochemical Survey: Data Release 2 – Total (coarse fraction), Aqua Regia (coarse and fine fraction), and Fire Assay (coarse and fine fraction) element contents
eCat Identifier - 126296,
UUID - 631937cb-d57f-45b1-9e39-a79961db391e
Source Information