Edwards, Jeffrey Scott, authorMcCallum, M. E. (Malcolm E.), 1934-, advisorBurns, L. K., committee memberWarren, C. Gerry, committee member2007-01-032007-01-031983http://hdl.handle.net/10217/88345Zip file contains supplementary plates 1 and 2.Geologic mapping and thin section petrography of rock units in and adjacent to the southwestern portion of the Mullen Creek mafic complex reveals the presence of a roof zone of a Precambrian layered basic intrusion that invaded a metavolcanic sequence (predominantly hornblende gneiss). This portion of the mafic complex consists of variably metamorphosed interlayered rocks that originally ranged from pyroxenite to anorthosite but were dominantly gabbro and leucogabbro. Most of these rocks underwent regional medium-grade metamorphism to form amphibolite facies assemblages in which hornblende has replaced pyroxene, labradorite has remained stable and relict igneous textures are preserved. A later episode of retrogressive low-grade metamorphism has produced locally abundant fractures, veinlets and minerals typical of the greenschist facies such as chlorite, epidote, talc, serpentine and saussurite.masters thesesZIPPDFengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.southern WyomingMedicine Bow MountainsProspect Mountain graniteBig Creek shear zonelayered mafic intrusionMullen Creek-Nash Fork shear zoneMullen Creek mafic complexnorthern Coloradohornblende gneissPetrology -- Medicine Bow Mountains (Colo. and Wyo.)Text