Mineralogy and Crystallographic Orientations of Inclusions within Vapor Phase Minerals of Topaz Bearing Rhyolite In Juab County, Utah

A sequence of volcanic events in response to the uplift and spreading of the Basin and Range, approximately 6.5 million years ago, led to the formation of multiple and extensive lava flows, domes, and tuffs in the Thomas Range of Juab County, Utah. The fluorine rich rhyolite lava flows are characterized by complex flow banding that is one of the most distinct features of the area at outcrop scale. This flow banding appears to have provided pathways for the transportation of vapors containing ions such as F, Si, O, Na, K, Fe, Mg, Ti, Ca, P, Al, Mn, Cl, Be, Sr, Li, Cr, Cs, Ba, Pb, Co, Ga, Sc, Y, Zr, Nb, Hf, Ta, Th, and U, which were then able to flow into the vugs allowing the formation of vapor phase minerals containing varying inclusions throughout the formation. Some of the common vapor phase minerals found in this area include topaz, quartz, garnet, hematite, pseudobrookite, bixbyite, red beryl, and fluorite; many of which are uncommon in silicic volcanic rocks. Over the years, several topaz specimens from Topaz Mountain and the red beryl from the 20 MYA Wah Wah Range were collected for the purpose of research at UWG. The first step in this research includes the creation of a series of thoroughly polished orthogonal thin sections from the rhyolite samples collected this is followed by orthogonal thin sections of several crystals from multiple vugs. Once completed, thin sections will be analyzed using the scanning electron microscope to map elemental composition. Additionally, this phase of the research will focus on the distribution of mineral inclusions in topaz and red beryl and the distribution of semi-trace elements in the Topaz Mountain topaz and red beryl from both Topaz Mountain and the Wah Wah Mountain.