New occurrences of the rare, REE minerals daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite from the Sheep Creek area, Montana, USA

Minerals
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Abstract

Over 30 small, discontinuous, tabular carbonatite bodies are located in the Sheep Creek area, Ravalli County, southwest Montana. The age and origin of these REE-Nb-rich deposits are currently being investigated. The purpose of this paper is to document the occurrence of several rare minerals, including daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite, in two of the carbonatite bodies. These minerals are found in association with monazite, hydroxylbastnäsite, ferriallanite, calcite, dolomite, baryte, quartz, actinolite, apatite, celsian, and Sr-rich aragonite. Automated SEM-EDS was used to target the areas of interest in polished specimens for more detailed spot SEM-EDS and electron probe microanalysis. Raman spectra were also acquired for each of the rare minerals. The complex mineralogy of the Sheep Creek carbonatites is most likely due to several overlapping thermal events, including primary magmatic, overprinting hydrothermal, and supergene weathering stages. The rare minerals described in this study are believed to be hydrothermal and/or carbothermal in origin, although no estimates of temperature are available at this time.

Publication type Article
Publication Subtype Journal Article
Title New occurrences of the rare, REE minerals daqingshanite, törnebohmite, biraite, sahamalite, and ferriperbøeite from the Sheep Creek area, Montana, USA
Series title Minerals
DOI 10.3390/min14101047
Volume 14
Issue 10
Year Published 2024
Language English
Publisher MDPI
Contributing office(s) Geology, Geophysics, and Geochemistry Science Center
Description 1047, 17 p.
Country United States
State Montana
Other Geospatial Sheep Creek Area
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