Abstract

The major roof pendants of the eastern Sierra Nevada, including the Bishop Creek, Pine Creek, Mount Morrison, Deadman Pass, Gull Lake, and part of the Northern Ritter Range and Log Cabin Mine pendants, are composed of continental-margin rocks ranging in age from Middle(?) Cambrian to middle(?) Permian. This group of pendants apparently is separated from all other exposures of Paleozoic rocks by faults, forming a geologic and geographic entity here referred to as the Morrison block. Here, for the first time, a common stratigraphy, consisting of 10 formational units, one named herein, is recognized throughout the pendants of the Morrison block, providing a basis for new correlations and regional interpretations.

Middle(?) Cambrian through Ordovician rocks of the Morrison block compare closely with rocks exposed south of Miller Mountain in west-central Nevada, suggesting paleogeographic continuity along an originally linear belt. In both areas rocks of this age are represented by deep-water, continental-margin sequences that contrast significantly with the dominantly platform deposits in the White-Inyo Range to the east. Devonian rocks, which in the Morrison block are represented by a submarine-fan system, can be traced into submarine channels in the western Inyo Mountains and thence onto the shelf in the eastern Inyo Mountains, providing a tie between these areas.

Eugeoclinal rocks now composing the Antler belt are distal equivalents of rocks in the Morrison block that were deposited and deformed during the Late Devonian–Early Mississippian Antler orogeny at a considerable distance to the west. Later, in post-Early Permian time, rocks of the Morrison block were deformed, rocks of the Antler belt were emplaced against the Morrison block, and the facies boundaries and structural belts defined here were offset on northwest-trending dextral faults.

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