Geologic Map of the Fittstown 7.5’ Quadrangle, Pontotoc and Johnston Counties, Oklahoma - Data Release

This 1:24,000-scale geologic map includes new geologic mapping as well as compilation and revision of previous geologic maps. Field investigations were conducted from 2009-2011, while also mapping and investigating the geology and hydrology of the Chickasaw National Recreation Area, west of the map area. The Fittstown quadrangle is in the northeastern part of the Arbuckle Mountains. The Arbuckle Mountains are composed of a thick sequence of Paleozoic sedimentary rocks that overlie Early Cambrian and Precambrian igneous rocks; these latter rocks are not exposed in the quadrangle. From middle to late Pennsylvanian time, the Arbuckle Mountains region was folded, faulted, and uplifted. Periods of erosion followed these Pennsylvanian mountain-building events, beveling this region and ultimately developing the current subtle topography that includes hills and incised uplands. The southern and northwestern parts of the Fittstown quadrangle are directly underlain by Lower Ordovician dolomite of the Arbuckle Group that has eroded to form a broad, stream-incised upland containing the broad, gently southeast-plunging, Pennsylvanian-age Hunton anticline. The northeastern part of the map area is underlain by Middle Ordovician to Pennsylvanian limestone, shale, and sandstone units that predominantly dip northeast and form the northeastern limb of the Hunton anticline; this limb is cut by steeply dipping, northwest-southeast striking faults of the Franks fault zone. This limb and the Franks fault zone define the southwestern margin of the Franks Graben, which is underlain by Pennsylvanian rocks in the northeast part of the map area.