A strontium isoscape of southwestern Australia  


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 (NGSA; www.ga.gov.au/ngsa). The present study targeted the Yilgarn geological region in southwestern Australia. The samples were mostly taken from a depth of ~60-80 cm (Bottom Outlet Sediments, BOS) in floodplain deposits at or near the outlet of large catchments (drainage basins). A small number of surface (0-10 cm) samples (Top Outlet Sediments, TOS) were also included in the study. For all, 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. Overall, 107 NGSA BOS < 2 mm and 13 NGSA TOS < 2 mm were analysed for Sr isotopes. Given that there are ~10 % field duplicates in the NGSA, all those samples originate from within 97 NGSA catchments, which together cover 533 000 km2 of southwestern Australia. Preliminary results for the BOS samples demonstrate a wide range of strontium isotopic values (0.7152 < 87Sr/86Sr < 1.0909) 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 appear to be consistent, in many places, with surface geology, regolith/soil type and/or nearby outcropping bedrock. For instance, catchments in the western and central Yilgarn dominated by felsic intrusive basement geology have radiogenic 87Sr/86Sr signatures in the floodplain sediments consistent with published whole-rock data. Similarly, unradiogenic signatures in sediments in the eastern Yilgarn are in agreement with published whole-rock data. 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.&nbsp; The new spatial dataset is publicly available through the Geoscience Australia portal https://portal.ga.gov.au/.</div>

Product Type

dataset

eCat Id

149755

Contact for the resource

  Resource provider

 

  Point of contact

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

  Point of contact

 

Digital Object Identifier

https://dx.doi.org/10.26186/149755

Keywords

( Project )
  • EFTF – Exploring for the Future
( Project )
  • National Database of Archived Samples
( Project )
  • Isotopic Atlas of Australia
( Project )
  • EFTF
( Project )
  • Australia’s Resources Framework
  • Mineral exploration
  • Sr isotopes
  • regolith
theme.ANZRC Fields of Research.rdf
  • Soil chemistry and soil carbon sequestration (excl. carbon sequestration science)Isotope geochemistryExploration geochemistry
  • Published_External

Publication Date

2024-08-11T23:44:21

Creation Date

2024-06-05T08:00:00

Security Constraints

Australian Government Security Classification System    

Classification - unclassified

Legal Constraints

Creative Commons Attribution 4.0 International Licence    

Use - license otherRestrictions

Status

completed

Purpose

Deliver strontium (Sr) isotopic data to EFTF stakeholders

Maintenance Information

asNeeded

Topic Category

geoscientificInformation

Series Information

Lineage

<b>Bibliographic references</b><br />CARITAT, P. de, DOSSETO, A. & DUX, F., 2022. A strontium isoscape of inland southeastern Australia, Earth Syst. Sci. Data, 14, 4271-4286, <br />https://doi.org/10.5194/essd-14-4271-2022<br /><br />CARITAT, P. de, DOSSETO, A. & DUX, F., 2022. A strontium isoscape of northern Australia, Earth Syst. Sci. Data, 15, 1655-1673, https://doi.org/10.5194/essd-15-1655-2023&nbsp; https://doi.org/10.5194/essd-15-1655-2023</div><div><br></div><div><b>Related to</b><br />CARITAT, P. de, DOSSETO, A. & DUX, F., 2022. A strontium isoscape of inland southeastern Australia. Geoscience Australia dataset, Canberra, Australia<br /> https://dx.doi.org/10.26186/146397<br /><br />CARITAT, P. de, DOSSETO, A. & DUX, F., 2022. A strontium isoscape of northern Australia. Geoscience Australia dataset, Canberra, Australia<br /> https://dx.doi.org/10.26186/147473</div>

Parent Information

Extents

[-34.5, -25, 115, 125]

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 - informed

A strontium isoscape of northern Australia    

eCat Identifier - 147473,

UUID - f7259782-43fa-433f-8784-50098b233ec1

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Source Information