Depositional environment for metatyuyamunite and related minerals from Caverns of Sonora, TX (USA)
Onac, Bogdan P.; Veni, George; White, William B.
European Journal of Mineralogy Volume 13 Number 1 (2001), p. 135 - 143
published: Jan 31, 2001
ArtNo. ESP147051301014, Price: 29.00 €
A new mineral association composed of metatyuyamunite, celestite, opal and several minor crystalline phases has been identified in the Caverns of Sonora (Texas). The minerals were identified by means of X-ray diffractometry and optical and scanning electron microscopy. The main component of this association is metatyuyamunite, a uranyl vanadate mineral that appears as aggregates of sub-millimeter platy-like crystals that are often covered by botryoidal opal coatings. The orthorhombic unit cell of the Sonora metatyuyamunite had parameters a = 10.418, b = 8.508, and c = 17.173 Å. Opal and celestite formed either directly over the yellow crust or along the cracks that traverse the limy mud on which metatyuyamunite was precipitated. The secondary uranium-vanadium minerals described herein were precipitated in the final stages of cave development.