High-Precision Geochronology of the Guadalupian Series (Middle Permian), West Texas and Southeastern New Mexico: Sequence Stratigraphic, Tectonic, and Time Scale Implications
University of Cincinnati, Department of Geology
Cincinnati, OH 45221-0013 [email protected]
The purpose of this study is to establish the first high-precision radiometric k-bentonite (altered volcanic ash) geochronology for the Guadalupian Series at its type locality, allowing for the testing and refinement of current regional sequence stratigraphic and tectonic models associated with the Permian Basin carbonate margin system. A refined geochronology based on absolute dating will also aid in calibrating the global time-scale.
K-bentonite beds have been collected in each of the three stages of the Guadalupian Series. Several of these have not previously been reported, including one in the lower Brushy Canyon Formation and two within and immediately below the Rader Member of the Bell Canyon Formation. These new finds augment those previously studied in the South Wells and Manzanita Member of the Cherry Canyon Formation. Of particular interest is the uppermost k-bentonite bed in the Manzanita Member that may provide an additional constraint of the timing of the boundary between Middle Guadalupian Wordian Stage and the Upper Guadalupian Capitanian Stage. A date at this position would also provide more accurate timing for the Illawarra Magnetic Reversal that is recognized near the top of the Wordian in the Guadalupe Mountains.
AAPG Search and Discovery Article #90070 © 2007 AAPG Foundation Grants in Aid