ABSTRACT: Late Paleozoic Paleolatitude and Paleogeography of the Midland Basin, Texas

WALKER, D. A., Mobil Exploration and Producing U.S., Midland, TX, J. GOLONKA, Mobil Exploration and Producing Services Inc., Dallas, TX, A. M. REID, Consulting Geologist, Midland, TX, and S. TOMLINSON REID, Consulting Geologist, Midland TX

During the Late Pennsylvanian through Early Permian, the Midland basin was located in the low latitudes. In the Desmoinesian (Strawn), the basin was astride the equator; during the Missourian (Canyon), the center of the basin had migrated northward so it was located at 1-2 degrees N latitude. In the Virgilian (Cisco), the basin center was located around 2-4 degrees N latitude, and by the Wolfcampian, it was positioned at around 4-6 degrees N latitude. From the Desmoinesian (312 Ma) through the Missourian (306 Ma), the relative motion of the basin was 63 degrees NE. Later during the Virgilian (298 Ma) to Wolfcampian (280 Ma), the direction of motion was 24 degrees NE. This change in motion reflects a major tectonic event, occurring between the Missourian and Virgilian, that greatly mod fied the movement of the Laurentian (North American) plate. At that time, Laurentia had collided with Gondwana and become part of the supercontinent Pangea. Throughout the late Paleozoic, Laurentia was rotated so the Midland basin was oriented 43 degrees northeast from its current setting.

Late Paleozoic paleogeography and paleolatitude controlled the direction of prevailing winds and ocean currents, thereby influencing the distribution of carbonate facies in the Midland basin. Present prevailing winds and ocean currents have been shown to have a major

impact on modern carbonate sedimentation and facies distribution in Belize, the Bahamas and Turks, and Caicos. A clearer understanding of how late Paleozoic latitude and geography affected sedimentation helps explain and predict the distribution of carbonates throughout the Midland basin.

AAPG Search and Discovery Article #91018©1992 AAPG Southwest Section Meeting, Midland, Texas, April 21-24, 1992 (2009)