Abstract

Vertically recurrent strata of cyclic carbonate and siliciclastic facies compose the Chase Group (Permian, Wolfcampian) in south-central Kansas. These rocks were deposited in shallow to relatively deepwater environments on a broad ramp. A complex hierarchy of stratigraphic cyclicity is evident in these strata. The basic genetic stratigraphic unit recognized is the cyclothem, defined as a package of transgressive-regressive strata. Higher frequency, upward-shallowing subtidal and peritidal cycles are recognized within the seven cyclothems identified in the Chase Group. Terrestrial lowstand systems tracts (LSTs) with red shales are considered to be maximum-emergence lowstand deposits, the presence of which conceptually allows definition of six presumed third- and fourth-order depositional sequences. Accordingly, cyclothems are higher frequency third- and fourth-order units, and component cycles, most of which are not regionally correlative, are mostly of autogenic origin. Cyclothem development appears to have been affected by Milankovitch-forced glacio-eustasy and tectonism.