Possible new Ca-REE-Bi phosphate minerals from a tungsten-rich calcsilicate skarn, Sierra Nevada Mountains, California
Abstract
Scanning electron microscope and electron microprobe analyses of 3 to 15 μm diameter grains present within a garnet-quartz granofels from a tungsten skarn reveal the possible existence of at least two new rare earth element (REE)-bearing phosphate phases: Ca(Ce,La,Bi,Nd)_2[(P,As)O_4]_2(OH)_2 and Ca(La,Ce,Nd,Pr,Bi)_2[(P,As)O_4]_2(OH)_2. The analyzed REEs constitute up to 50 wt% of the phases; bismuth oxide contents range from 4.1 to 16.1 wt%. Structural data has proved impossible to obtain from these tiny grains, presumably due to radiation damage by thorium decay. These potentially new phosphate minerals are present within alteration assemblages of REE-rich epidote crystals, as well as along grain boundaries and cracks cross-cutting the quartz-garnet host rock. Association with the zeolite brewsterite-Ba suggests that these hydroxyl phosphates formed during water-rich, low-temperature, retrograde mineralization in the skarn environment.
Additional Information
© 2015 Mineralogical Society of America. Manuscript Received March 4, 2014. Manuscript Accepted August 31, 2014. SEM, EBSD, and EPMA analyses were carried out at the Caltech GPS Division Analytical Facility, which is supported, in part, by NSF Grants EAR-0318518 and DMR-0080065. Funding for this study was provided by a grant from the California State University system. Landowners of the Consolidated Tungsten Mine are thanked for providing access, and the Chrisman family is thanked for generous field support. Discussions with B. Browne, L. Meinert, R. Newberry, W. Nokleberg, J. Preston, J. Pyle, L. Robb, G. Rossman, and F. Spear improved the content of this study, as did comments by Francis McCubbin and an anonymous reviewer.Additional details
- Eprint ID
- 56380
- Resolver ID
- CaltechAUTHORS:20150406-131547892
- EAR-0318518
- NSF
- DMR-0080065
- NSF
- California State University system
- Created
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2015-04-06Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field