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Blue lace agate and chalcedony pseudomorphs from Ysterputs in southern Namibia.
- Source :
-
Journal of African Earth Sciences . Apr2024, Vol. 212, pN.PAG-N.PAG. 1p. - Publication Year :
- 2024
-
Abstract
- The Blue Lace Agate mine exploited a hydrothermal vein deposit at Ysterputs in southern Namibia until 2017. The deposit occupies a shear zone and associated fractures in a Jurassic dolerite sill that intruded a Permian marine deposit. Much of the chalcedony constituting the agate is the length-slow variety 'quartzine', indicating deposition in a saline environment, presumably derived from the marine sediments. Associated minerals are dolomite, forming an initial coating on the fissure wall and brecciated dolerite fragments, as well as late-stage crystals of ankerite, calcite, dolomite, gypsum and quartz. Ysterputs is also the source of cubic chalcedony pseudomorphs, originally thought to be after fluorite, but probably after melanophlogite. • Chemical results of the minerals of the blue lace agates from Ysterputs in southern Namibia, including calcite and dolomite. • Micrographs of the length-slow 'quartzine' in agate, believed to originate from marine sediments of the Whitehill formation. • Presence of cubic chalcedony pseudomorphs, probably after melanophlogite. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 1464343X
- Volume :
- 212
- Database :
- Academic Search Index
- Journal :
- Journal of African Earth Sciences
- Publication Type :
- Academic Journal
- Accession number :
- 175963069
- Full Text :
- https://doi.org/10.1016/j.jafrearsci.2024.105211