Version 1
: Received: 14 August 2024 / Approved: 14 August 2024 / Online: 14 August 2024 (16:53:15 CEST)
How to cite:
Sergeev, N.; Collins, T. Regolith-hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls. Preprints2024, 2024081070. https://doi.org/10.20944/preprints202408.1070.v1
Sergeev, N.; Collins, T. Regolith-hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls. Preprints 2024, 2024081070. https://doi.org/10.20944/preprints202408.1070.v1
Sergeev, N.; Collins, T. Regolith-hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls. Preprints2024, 2024081070. https://doi.org/10.20944/preprints202408.1070.v1
APA Style
Sergeev, N., & Collins, T. (2024). Regolith-hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls. Preprints. https://doi.org/10.20944/preprints202408.1070.v1
Chicago/Turabian Style
Sergeev, N. and Tiffany Collins. 2024 "Regolith-hosted Rare Earth Element Mineralization in the Esperance Region, Western Australia: Major Characteristics and Potential Controls" Preprints. https://doi.org/10.20944/preprints202408.1070.v1
Abstract
A number of regolith-hosted REE occurrences have recently been discovered in the Esperance region in southern Western Australia. This paper summarizes major characteristics of the REE mineralization and discusses contributing factors and potential controls. The main aim is to explain why there is a lack of highly sought-after ion-adsorption clay type REE deposits across the region despite the presence of the regolith-hosted REE mineralization on a regional scale. Local mineralization mostly occurs as continuous flat-lying enrichment “blankets” within the residual regolith developed over Archaean–Proterozoic granite gneisses and granitoids with elevated REE content. The enriched horizon is commonly located in the lower saprolite and saprock and is accompanied by an overlying REE-depleted zone. This distribution pattern, together with the data on HREE fractionation and the presence of the supergene REE minerals, indicate chemogenic type enrichment formed by supergene REE mobilization into groundwater, downward transport and accumulation in the lower part of the weathering profile. Residual REE accumulation processes due to bulk rock volume and mass reduction during weathering also contribute to mineralization. It is proposed that climate and groundwater chemistry are the critical controls on the distribution of REEs in the weathering profile and on their speciation in the enrichment zone. Cenozoic aridification of climate in southwest Australia heavily overprinted pre-existing REE distributions in the weathering profile. Acidic (pH <4), highly saline groundwaters intensely leached away any relatively weakly bound, adsorbed or colloidal REE forms, moving them downward. Dissolved RREs precipitated as secondary phosphates in neutral to alkaline environment at lower Eh near the base of the weathering profile forming the supergene enrichment zone. Low denudation rates, characteristic of areas of low relief under the arid climate, are favorable for the preservation of the existing weathering profiles with REE mineralization.
Environmental and Earth Sciences, Geochemistry and Petrology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
