--> Abstract: Sequence Stratigraphy and Biostratigraphy of a Mixed Carbonate-Siliciclastic Ramp: Lower Carboniferous Mount Head Formation, Southwest Alberta, Canada, by R. T. Brandley and F. F. Krause; #91012 (1992).
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ABSTRACT: Previous HitSequenceNext Hit Previous HitStratigraphyNext Hit and Previous HitBiostratigraphyNext Hit of a Mixed Carbonate-Siliciclastic Ramp: Lower Carboniferous Mount Head Formation, Southwest Alberta, Canada

BRANDLEY, RICHARD T., and FEDERICO F. KRAUSE, University of Calgary, Calgary, Alberta, Canada

The Mount Head Formation consists of mixed carbonate-siliciclastic sediments deposited in a broad embayment of the western North American paleocoastline on a gently sloping, westward-deepening ramp.

Previous HitSequenceNext Hit stratigraphic relationships are constrained by coral and foraminiferal Previous HitbiostratigraphyTop that provides time relationships at the approximate scale of parasequence sets. Basin fill is represented by three to four cycles of retrogradational and progradational parasequence sets. Retrogradational parasequence sets consist of western, normal marine, poorly sorted wackestone and packstone beds, and mid-ramp carbonate-sand shoal complexes that onlap eastern, restricted shelf, and sabkha deposits. Onlapped surfaces are sharp, undulating, unconformable marine flooding surfaces. Each surface represents synchronous, submarine, sea-floor exposure, modified subsequently by submarine processes and then covered diachronously by onlapping sediments.

Progradational parasequence sets consist of (1) eastern, restricted shelf, and sabkha sediments and mid-ramp carbonate-sand shoal deposits that downlap onto underlying, carbonate-sand shoals, and (2) western carbonate-sand shoal sediments that downlap onto deep-water, poorly sorted wackestone and packstone beds. Downlapped surfaces are maximum marine flooding surfaces. These surfaces are observed locally and are inferred to exist regionally from observed stacking patterns. Downlapping depositional facies are separated by sharp boundaries that are locally disconformable.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)