MISSISSIPPIAN STRATIGRAPHY OF SOUTH-CENTRAL OKLAHOMA

Mississippian (Kinderhookian and Osagean) strata in south-central Oklahoma (Arbuckle and Lawrence uplifts and Ardmore basin) are distinctly different from equivalents that outcrop in the Ozarks. Post-Woodford Kinderhookian strata consist of less than 0.5 to 1.0 m of pre-Welden shale on the Lawrence uplift and south flank of the Arbuckle uplift. The Welden Limestone (thickness <2.0 m) is a diminutive representative of the lower and middle Osagean, which consists of tens of meters of “Boone” rocks on the Burlington Shelf. The Meramecian consists of the Sycamore Limestone (Arbuckle uplift) and the Caney Shale (Lawrence uplift and Ardmore basin). The lower Sycamore Limestone is spicular silty limestone/calcareous siltstone with minor interbedded shale that is coeval to more basinal silty shales of the Ahloso Member of the Caney Shale. The shelfal Sycamore Limestone contains phosphatic shale in the upper part that correlates to the Delaware Creek Member of the Caney Shale on the Lawrence uplift. Chesterian Caney shale on the Lawrence Uplift includes the upper part of the Delaware Creek Member and the Sand Branch Member. In the Ardmore basin, Meramecian Sycamore limestone grades upward into siltstones and silty shales of the Chesterian Caney. The Ardmore Caney Shale is succeeded by the dark-colored Goddard Shale, which is equivalent to the dark gray Sand Branch Member of the Caney Shale on the Lawrence Uplift, and the Fayetteville Shale of Arkansas. The Sycamore-Caney-Goddard transition and Ahloso-Delaware Creek-Sand Branch succession are interpreted as representing the gradual deepening of the Mississippian sea across the Meramecian and Chesterian stages.