The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite

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Carbonatite-hosted rare earth element (REE) deposits are the primary source of the world’s light REEs and have the potential to be a source of heavy REEs. The Mount Weld REE deposit in Western Australia is hosted in a lateritic sequence that reflects supergene enrichment of the underlying carbonatite complex. Similar to other carbonatite-related ore deposits, ore from Mount Weld displays extreme light REE (LREE) enrichment (La up to 4 wt. %), but in contrast also contains substantially higher concentrations of heavy REEs (HREEs). REE enrichment in the laterite is controlled by the breakdown of primary minerals, the release and transport of REEs, and the formation of secondary minerals. Secondary REE-bearing phosphate minerals are the primary REE-host phases in the laterite ore with monazite as the dominant phase; other REE-bearing phases include rhabdophane, cerianite, churchite, florencite, and crandallite subgroup minerals. Profiles through the laterite show that in the REE-rich zone, apatite and primary calcite have broken down, and dolomite decreases by approximately 60-100%, such that the loss of Ca and Mg, as well as Si and K, leads to a relative increase in the REEs. Sequestering of REEs in secondary mineral phases formed by groundwater further enhances the REE concentration.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title The Mount Weld rare earth element deposit, Western Australia: A carbonatite-derived laterite
Volume 3
Year Published 2023
Language English
Publisher Society for Geology Applied to Mineral Deposits
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description 4 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings of the 17th SGA biennial meeting
First page 236
Last page 239
Conference Title 17th Biennial SGA Meeting
Conference Location Zurich, Switzerland
Conference Date August 28 - September 1, 2023
Country Australia
Other Geospatial Mount Weld mine
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