Product catalogue
Hydrogeochemistry to explore the Georgina Basin’s phosphate potential
With the increasing need to extend mineral exploration under cover, new approaches are required to better understand concealed geology, and to narrow the mineral prospectivity search-space. Hydrogeochemistry is a non-invasive exploration technique based on the premise that groundwater interacting with a deposit or supergene alteration can cause anomalous elemental and isotopic signatures down-gradient. Water chemistry can reflect mineralisation directly, but can also reveal other key components of a mineral system, including fluid-flow pathways (e.g. fault/fracture zones), evidence for mineral system traps (e.g. evaporites, shales), or metal sources (e.g. mafic rocks).
The Northern Australia Hydrogeochemical Survey (NAHS) was a multiyear regional groundwater sampling program that aimed to understand the regional mineral potential within the Tennant Creek to Mt Isa area (Schroder et al. 2020). This presentation will explore the application of NAHS for investigating mineral potential of a region and present a workflow for establishing spatial or lithological baselines to evaluate hydrogeochemical anomalies.
The Georgina Basin is well known for its phosphate potential, with several >1Mt deposits discovered in recent years such as Amaroo and Wonarah; however, the basin has been largely unmapped in terms of phosphate distribution under cover. This work focuses on a subset of 160 NAHS samples collected within two predominant aquifers of the Cambrian Georgina Basin (and time equivalents in the Wiso Basin). This focus restricts us to samples which experience a similar climate, recharge conditions, and aquifer compositions, reducing the hydrogeochemical variation that can mask intra-aquifer anomalies.
Elevated dissolved phosphate, PO43- (normalised to HCO3- or Cl-), is observed in the groundwater on the eastern margin of the Georgina Basin. This region is known for Cambrian phosphorite deposits, with sampled bores proximal to a number of near-surface Georgina Basin phosphate deposits. We tested trace element (i.e. U, V and REEs) concentrations as a tool for discriminating phosphate dissolution, however at this regional scale of sampling, possible anomalies were only seen in few bores, thus it is difficult to conclude if this is a consistent relationship robust enough for exploration.
More promising may be the use of REE ratios as another indicator of proximity to a phosphate deposit. Emsbo et al. (2015) note that REE compositions of phosphates are relatively consistent globally within a geological period. REE spidergrams of the high PO43- waters are similar to the average REE spidergram of Cambrian phosphates, which contrasts to the REE spidergram of low PO43- groundwaters. Cerium and Europium deviations make this relationship less diagnostic, thus we explore a series of REE ratios (i.e. Er/Dy, Er/Gd, Sm/Nd) for characterising PO43- relationships in groundwater, and use this to suggest other regions of the Georgina Basin with potential for subsurface phosphate deposits.
References:
Emsbo, P., McLaughlin, P.I., Breit, et al., 2015. Rare earth elements in sedimentary phosphate deposits: solution to the global REE crisis? Gondwana Research, 27(2), 776-785. Schroder, I.F., Caritat, P. de, Wallace, L., et al., 2020. Northern Australia Hydrogeochemical Survey: Final Data Release and Hydrogeochemical Atlas for EFTF. Geoscience Australia, Canberra. http://dx.doi.org/10.11636/Record.2020.015
Abstract presented at the 2021 Australian Earth Sciences Convention (AESC)
Simple
Identification info
- Date (Creation)
- 2020-10-09
- Date (Publication)
- 2024-10-09T00:21:51
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/144427
Identifier
- Codespace
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Digital Object Identifier
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Role Organisation / Individual Name Details Author Schroder, I.F.
Author de Caritat, P.
Publisher Commonwealth of Australia (Geoscience Australia)
Voice
- Name
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Australian Earth Sciences Convention (AESC) 9-12 February 2021 Hobart, Tas
- Purpose
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An abstract submitted to AESC21
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- Pending
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Resource provider Minerals, Energy and Groundwater Division
External Contact Point of contact Schroder, I.
MEG Internal Contact
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- Geoscientific information
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Extent
))
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- As needed
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Product data repository: Various Formats
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Data Store directory containing the digital product files
Data Store directory containing one or more files, possibly in a variety of formats, accessible to Geoscience Australia staff only for internal purposes
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EARTH SCIENCES
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- Discipline
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hydrogeochemistry
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- Place
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Georgina Basin
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- Feature type
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Phosphate
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- Project
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Exploring for the future - EFTF
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- Project
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Northern Australia Hydrogeochemical Survey - NAHS
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- Discipline
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groundwater
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- Feature type
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Rare earth element - REE
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- Keywords
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Published_External
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Resource constraints
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Creative Commons Attribution 4.0 International Licence
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CC-BY
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4.0
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© Geological Society of Australia Inc. 2021
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Australian Government Security ClassificationSystem
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
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Link to Abstract Volume (p190)
Link to Abstract Volume (p190)
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Download Presentation (pdf) [2.1 MB]
Download Presentation (pdf) [2.1 MB]
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pdf
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nil
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An abstract submitted to AESC21
Metadata constraints
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Australian Government Security Classification System
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urn:uuid/69e82138-5d05-4cfd-b0e2-44b7620eb024
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MEG Internal Contact
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Conference Abstract
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Geoscience Australia - short identifier for metadata record with
uuid
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- Date info (Creation)
- 2019-04-08T01:55:29
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Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
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ISO 19115-1:2014
Metadata standard
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ISO 19115-3
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
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Version 2.0, September 2018
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