Print this pageABSTRACT: Arbuckle Group Depositional Cycles, Southern Oklahoma
Robert F. Lindsay, Kathy M. Koskelin
Outcrop and/or subsurface core studies of Butterly Dolomite, Cool Creek, Kindblade, and West Spring Creek formations reveal most of the Arbuckle Group to have been deposited as a series of storm-dominated, shallowing-upward sequences. They were deposited upon an extremely broad, nearly flat carbonate ramp that formed the southern margin of the North American craton (Knox, Arbuckle, Ellenburger, and El Paso groups) in the Upper Cambrian and Lower Ordovician.
Shallowing-upward sequences were deposited in a cyclic manner, with individual fifth-order cycles only a few feet to tens of feet thick. These cycles record abrupt transgressions, caused by quick sea level rise, followed by progradation of a paleoshoreline as sea level gradually fell. Each cycle is divided into subtidal and tidal-flat components. Subtidal and tidal-flat components can be of equal thickness or can be skewed with one component becoming dominant and the other subordinate.
Only half of all cycles are complete shallowing-upward sequences. Once understood, the vertical stacking of facies in a cycle is predictable so that complete vs. incomplete cycles can be easily recognized. These distinctions are very important to recognize because well-developed subtidal portions of a cycle can form reservoir intervals when dolomitized.
AAPG Search and Discovery Article #91003©1990 AAPG Annual Convention, San Francisco, California, June 3-6, 1990