Mount Morrison Roof Pendant Geology

Type area is along john muir trail between mount morrison roof pendant and wheeler crest and pine creek septa on east and potter pass septum on west sierra nevada ca bateman 1992.

Mount morrison roof pendant geology.

Mount morrison consists of a roof pendant that underlies an area of 62 km 2 24 sq mi. Metasedimentary rocks of the mount morrison roof pendant just south of long valley caldera gave 87 sr 86 sr values that range from 0 7090 to 0 7250 goff et al 1991. Late cretaceous type section locality area and or origin of name. Evidence for its original paleogeographic position.

Pelitic rocks in the mount morrison pendant some distance from any pluton contain biotite muscovite quartz k feldspar and andalusite or cordierite the mineral composition yielding maximum pressures of 2 0 2 2 kbar at temperatures of 600 615 c data of j. In the mount morrison pendant structures produced during the morrison orogeny apparently were later refolded twice prior to sinistral displacement on the laurel convict fault which cross cuts. Granitoid plutons underlying the volcanic field have given 87 sr 86 sr values ranging from 0 70666 to 0 70987 and many other sierran plutons nearby range from 0 707 to 0 715 goff et al 1991. This roof pendant is host to the pine creek mine deposits which have produced significant amounts of tungsten as well as accessory molybdenum copper silver and gold newberry 1982.

These rocks developed along the passive western continental margin of north america during the middle devonian. The mount diablo ophiolite contra costa county california. The metamorphic rock composing the mount morrison roof pendant block is the relict of a paleozoic sedimentary sequence overprinted by several deformation events which left the rocks isolated atop the sierra nevada batholith. Biostratigraphy of upper paleozoic rocks in the mount morrison roof pendant sierra nevada california.

The mount morrison roof pendant the only roof pendant in the central sierra nevada containing paleozoic fossils is complexly deformed and contains three generations of structures including folds reverse faults schistosities and lineations. Sorensen 1988 personal commun.