Depositional environments of the Oil Creek Sandstone (Ordovician), Arbuckle Mountains, Oklahoma

By

Alton A. Brown, Consultant, 1603 Waterview Drive, Richardson, TX 75080

Depositional setting of the sandstone member of the Oil Creek Formation in the Arbuckle Mountains is problematic, because sedimentary structures are rarely preserved. The exception is the Barnes pit #1 quarry (south of Sulphur), where asphalt lithification enhances sedimentary structures in the upper part of the sandstone member and the lower part of the limestone member.

The sandstone section consists of two interstratified facies associations. One is thin-bedded with tabular crossbed sets, tabular ripples, and parallel lamina separated by dominantly planar bounding surfaces. This unit contains vertical burrows as well as escape structures and rare feeding traces. The other facies association is becomes more dominant up section. It comprises festoons with southerly transport direction forming thicker, lenticular sandstone beds with concave-upward bounding surfaces. No biogenic structures were observed. The gradational contact with the limestone member is a structureless, medium-bedded calcareous sandstone with a few indistinct burrows. The lowest limestone is sandy, with probable algal laminations and sand-filled desiccation cracks. Higher limestone beds are bioturbated with variable sand and fossil content and some hardgrounds.

The sandstone is interpreted as a shallow neritic marine sand, where the sand was unstabilized, reducing the biodiversity and decreased biogenic structure preservation. The transition from sand to carbonate deposition appears to be related to stabilization of the shallow neritic sand flat, initially by algal mats. It is probable that the sand flat built to sea level (or sea level dropped), because the lowest carbonate intervals have characteristics of tidal flat deposits.

AAPG Search and Discovery Article #90010©2003 AAPG Southwest Section Meeting, Fort Worth, Texas, March 1-4, 2003