Preliminary report on the distribution of copper and platinum group metals in mafic igneous rocks of the Sierra Madre, Wyoming

Abstract

Published reports on the more recent work are by Ferris (1966) on the gneissic basement near Encampment, and by Ebbett (1970) on the metasedimentary rocks. Geologic maps of the various areas are available through the Geological Survey of Wyoming, Laramie. No age determinations are available for the Sierra Madre, but extensive collections have been made by F. Allan Hills and R. S. Houston and are currently being studied by Hills at the State University of New York at Buffalo.

New models for Paleoproterozoic orogenesis in the Cheyenne belt region: Evidence from the geology and U-Pb geochronology of the Big Creek Gneiss, southeastern Wyoming

“…This body also corresponds to a prominent aeromagnetic high (see Sims et al, 2001, their plate 2). The relatively isolated nature of this body on the aeromagnetic map supports the idea that this body represents a discrete mafi c complex, as suggested by Houston et al (1975). The gabbroic rocks east of the Quimby Park fault strongly resemble rocks from the Mullen Creek complex, and, similar to Houston (1993), we interpret them as likely correlative to the Mullen Creek complex, separated by the later extension of the Saratoga Valley.…”

Progress report on the study of radioactive quartz-pebble conglomerate of the Medicine Bow Mountains and Sierra Madre, southeastern Wyoming

“…The middle Precambrian miogeosynclinal metasedimentary rocks were formerly divided into two parts: (1) the Deep Lake Formation of the Medicine Bow Mountains and the metasedimentary rocks of the Sierra Madre that are thought to be its equivalent; and (2) the rocks of the Libby Creek Group (Houston and others, 1968) of the Medicine Bow Mountains, which unconformably overlie the Deep Lake Formation. A discussion of the relationship between these two rock sequences can be found in Houston and others (1968) and Houston, Schuster, and Ebbett (1975). The following discussion emphasizes the Deep Lake Formation and its equivalents because of their potential for uranium and new information on the stratigraphy is introduced.…”

“…During the 1960's and 1970's, geologic studies of Precambrian rocks in Wyoming were continued at the University of Wyoming, with particular emphasis on the Sierra Madre. A preliminary report on the miogeosynclinal rocks of the Sierra Madre was published as a result of a study jointly sponsored by the U.S. Geological Survey and the Geological Survey of Wyoming (Houston, Schuster, and Ebbett, 1975). This report called attention to the strong resemblance of miogeosynclinal metasedimentary rocks of the Sierra Madre to rocks of the Deep Lake Formation of the Medicine Bow Mountains.…”

“…(Cloud, 1968;Roscoe, 1973). Houston, Schuster, and Ebbett (1975) again emphasized the lithologic resemblance of the Sierra Madre and Medicine Bow miogeosynclinal rocks to the Canadian Huronian, and they suggested that a more definitive correlation might come from additional isotopic studies (a more closely bracketed age determination) or from proof that the pyritic conglomerates that seem to characterize rocks of early middle Precambrian age (2,500-2,000 m.y.) are present in the Wyoming successions.…”

Geological and geochemical investigations of uranium occurrences in the Arrastre Lake area of the Medicine Bow Mountains, Wyoming

“…The determination of uranium in water and in organic-rich bog material is also recommended. Stratigraphic descriptions of these rocks are in Houston and others (1968) for the Medicine Bow Mountains and in Houston, Schuster, and Ebbett (1975) for the Sierra Madre. Virtually all geologists who have examined these rocks, beginning with Van Hise and Leith (1909) and continuing with Blackwelder (1935), Houston and others (1968), Young (1970) and Houston, Schuster and Ebbett (1975), have noted the strong lithologic resemblance of these metasedimentary rocks with those of Early Proterozoic age (Early Precambrian X) on the north shore of Lake Huron.…”