Abstract: What's New in Oklahoma's Old Basement

GILBERT, M. CHARLES, and JOHN P. HOGAN

Ham, Denison and Merritt (1964) laid the groundwork for trying to understand the importance and control of the basement in the development of subsequent stratigraphy and structure of the Mid-Continent. The map of the Geologic Provinces of Oklahoma produced by Northcutt and Campbell (1996) prompts a new look at the character of the basement. What are the cover rock-basement relationships? Can we read something about the basement from the Geologic Province Map? Can we "predict" Paleozoic structure and stratigraphy from a knowledge of the basement?

It is clear that basement features are involved in definitions of the major provinces, the most profound being the contact between the younger basement of the Southern Oklahoma Aulacogen and the older basement of the northern Arbuckles. This boundary, well-defined on the north of the SOA, splits the Arbuckle Uplift in two and separates the Wichita Uplift and Anadarko Basin. New dating of this younger basement reveals a compressed time interval for its formation (approx. 525-540 Ma), and implies substantial erosion before deposition of the Upper Cambrian Timbered Hills Group and the Arbuckle Group. The extent of the dense fin of new rock defines the core of the SOA and determined the positions of some of the major Pennsylvanian thrust faults. Some are presumably reactivated Cambrian normal faults.

There is evidence from gravity that the Anadarko Basin lies across an extension of the older Mid-continent Rift (1.1 Ga). This may have a relation to the largest overhang or the Mountain View Fault, and the placement of the Cyril Basin, Cement Fault, etc.

Puzzling questions remaining are Why the Nemaha Uplift, and Where is the other half of the Arbuckle basement?

AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma