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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 67 (1983)

Issue: 8. (August)

First Page: 1349

Last Page: 1349

Title: Depositional Environment of Leo Sands, Middle Minnelusa Formation, Niobrara County, Wyoming: ABSTRACT

Author(s): J. Duncan McBane, Robert P. Swinehart

Article Type: Meeting abstract


The Upper Pennsylvanian middle Minnelusa Formation "Leo Sands" in the north half of Niobrara County, Wyoming, and southwestern South Dakota, may have been deposited in a nearshore eolian sabkha environment. Cores reveal sedimentary features which support this hypothesis, such as deflation lags, avalanche-produced strata, probable interdune deposits, and nodular anhydrites.

The "Leo Sands" have proven to be excellent reservoir rocks. Associated anhydrites provide the seal for hydrocarbons which may have been generated from organic-rich interdunal shales.

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Copyright 1997 American Association of Petroleum Geologists