Distribution of lithium in Australian regolith: an indicator of potential lithium resources in salt lake brines?  

Authors / CoAuthors

de Caritat, P. | Jaireth, S. | Bastrakov, E.N. | Grunsky, E. | Mann, A.

Abstract

Lithium (Li) concentrations in catchment outlet sediment samples were measured as part of the National Geochemical Survey of Australia (NGSA; www.ga.gov.au/ngsa). Samples were collected at or near the outlet of 1186 catchments covering ~81% of Australia during 2007-2009. At each site a top outlet sediment (TOS) sample (0-10 cm depth) and a bottom outlet sediment (BOS) sample (~60-80 cm depth) were collected; each split into a 'coarse' (<2 mm) and a 'fine' (<75 mm) grain-size fraction. Li data is available for the Mobile Metal Ion (MMI®; TOS 'coarse' only) and Aqua Regia (AR) digestion techniques. Censored data (reported to be below the Lower Limit of Detection, LLD) account for 32% of the MMI® data (LLD = 0.005 mg/kg) and are absent from the AR dataset (LLD = 0.1 mg/kg); replacement values were imputed using a nearest neighbour method. The median MMI® value is three orders of magnitude lower than the median AR concentration. Further, there is an increase in median Li for the AR digestion following the order TOS 'coarse < BOS 'coarse' < TOS 'fine' < BOS 'fine'; in other words the deep or 'fine' samples have higher Li concentrations than their surface or 'coarse' counterparts. In order to assess the 'availability' of Li, the ratio of MMI® to AR Li (Li_Mi/Ai) was calculated and plotted. Li availability ranges from almost non-existent up to 14%. The map of Li_Mi/Ai shows that the regions of high Li availability correspond to the Yilgarn Craton, much of eastern South Australia, the southernmost, westernmost and central Northern Territory, south and western Queensland, western New South Wales and Victoria and a few coastal areas. These commonly are regions where salt lakes occur. However, assessment of Li content of source rocks and groundwaters and absence of active hydrogeological setting highlight limitations for the potential for Li-rich brines in Australian salt lakes.

Product Type

nonGeographicDataset

eCat Id

76317

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Keywords

• External PublicationAbstract

( Theme )

• geochemistry

( Theme )

• regolith

( Theme )

• mineral exploration

• AU

Australian and New Zealand Standard Research Classification (ANZSRC)

• Geochemistry

• Published_Internal

Publication Date

2013-01-01T00:00:00

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

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notPlanned

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geoscientificInformation

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National Geochemical Survey of Australia (NGSA)

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Extents

[-44.0, -10.0, 112.0, 154.0]

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National Geochemical Survey of Australia (NGSA) 112.0 154.0 -44.0 -10.0 N/A