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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 3. (March)

First Page: 495

Last Page: 496

Title: Cretaceous Transgression of Coahuila Peninsula, Potrero de la Mula and Sierra del Fuste, Coahuila, Mexico: ABSTRACT

Author(s): James W. McKee, Norris W. Jones, Thomas S. Laudon, Benjamin Marquez D.

Article Type: Meeting abstract

Abstract:

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Exposures of the Late Jurassic to Early Cretaceous Coahuila peninsula have been reported at three localities northwest of Torreon and at Potrero de la Mula in central Coahuila. Exposures also occur at Sierra del Fuste, about 25 km northwest of the La Mula outcrops. At Potrero de la Mula, granites to granodiorites containing xenoliths are cut by dikes of six ages. Deep pre-Cretaceous weathering, thin transgressive arkose, and overlap by the Padilla Formation confirm these as basement rocks.

In early Neocomian time the basement was a source of detritus for the basinward San Marcos Formation. Subsequently, seas partly covered the La Mula area, depositing the lagoonal facies (Oballos Member) of the Padilla Formation, which thins to a featheredge against the higher parts of the basement. A 1 to 2-m arkose, which seems restricted to paleotopographic lows, is present at the base of the Padilla. Overlying the Padilla, marine shales and a progradational sequence of fluvial and marginal-marine sandstones compose the La Mula Formation. Upper La Mula shales grade upward into sabkha deposits of the lower La Virgen Formation. Normal-marine shelf conditions existed at Potrero at several different times, causing carbonate tongues to be deposited in the La Virgen Formation and ultimatel forming the Cupido Formation. Possible subaerial exposure of the Cupido preceded deposition of the La Pena shales and calcareous mudstones, which grade upward into calcareous mudstones of the Aurora Formation.

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