The Mississippian Antler Foreland and Continental Margin in Southern Nevada: The Eleana Formation Reinterpreted
CASHMAN, PATRICIA H., and JAMES H. TREXLER, JR., University of Nevada, Reno, NV
Rocks mapped as the Mississippian Eleana Formation at the type locality on the Nevada Test Site appear to comprise two completely different, but coeval, sedimentary units. In the Eleana Range (Western Eleana Formation), the strata are siliciclastic and carbonate turbidites of Mississippian age. From immediately east of the Eleana Range to Syncline Ridge (Eastern Eleana Formation), the strata are Devonian-Mississippian mudstone and quartzite conformably overlying Devonian limestone and underlying Pennsylvanian limestone. Although the contact between the two sedimentary packages is not exposed, small-scale structures document an east-dipping fault contact and reverse motion.
Sandstone petrography and stratigraphic considerations support the age data in identifying two separate Mississippian units. Sandstones from the Western Eleana are chert litharenites with significant amounts of feldspar and both volcanic and sedimentary lithic grains. These rocks are interpreted to be a submarine fan deposit; southwest-directed paleocurrent indicators suggest that they were deposited in an elongate trough, filled axially from the northeast. The source of the sediments was the Antler allochthon and foreland basin. We tentatively correlate this section with the Dale Canyon-Chainman-Diamond Peak section near Eureka, Nevada. Sandstones from the Eastern Eleana are quartz arenites with rare chert and detrital heavy minerals. These strata are tentatively interpreted to be a hallow shelf deposit, with sediments derived from the continent to the east. We tentatively correlate this section with the Guilmette-Pilot-Scotty Wash-Chainman section of eastern Nevada. These sedimentary systems were initially separated an unknown distance across the late Paleozoic continental margin.
AAPG Search and Discovery Article #91009©1991 AAPG-SEPM-SEG-SPWLA Pacific Section Annual Meeting, Bakersfield, California, March 6-8, 1991 (2009)