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U-Pb detrital zircon study of the Pennsylvanian clastics in north-central Texas

Session: Advances and Applications in Geochronology for Interpreting Stratigraphic and Basin Records (Posters)

Presenting Author:

Xiangyang Xie

Authors:

Xie, Xiangyang¹, Busbey, Arthur B.², Stockli, Daniel F.³, Stockli, Lisa Danielle⁴

(1) Dept. of Geological Sciences, Texas Christian University, Fort Worth, TX, USA, (2) Dept. of Geological Scciences, Texas Christian University, Fort Worth, TX, USA, (3) Dept. of Earth and Planetary Sciences, University of Texas at Austin, Austin, TX, USA, (4) University of Texas at Austin - Jackson School of Geosciences, Austin, TX, USA,

Abstract:

In total, eighteen Pennsylvanian clastic samples (six from cores and twelve from outcrops) have been collected from north-central Texas to understand the regional and local tectonism and its impact on sedimentation on the southern margin of Laurentia. U-Pb detrital zircon ages of Pennsylvanian clastic samples span from Archean to early Paleozoic time. Early Pennsylvanian conglomerate samples (Atokan age) are characterized by a predominate Mesoproterozoic age peak at ~1.35Ga, suggesting that those grains were dispersed from the uplifts to the north, such as the Red River uplift and the Muenster Arch that are associated with the Amarillo-Wichita-Arbuckle Mountains. In contrast to Atokan age samples, all Middle to Upper Pennsylvanian clastics (Des Moines, Missouri, and Virgil age) samples are characterized by major age peaks from Neoproterozoic–Paleozoic (800-500 Ma) and Grenvillian (1250-900 Ma) with minor age peaks from the Archean (>2.5 Ga), Late Paleoproterozoic to early Mesoproterozoic (1.8-1.3 Ga), and early Paleozoic (500–300 Ma), suggesting there was a major source shift and a different dispersal pattern starting in the Middle Pennsylvanian relative to the Early Pennsylvanian. Based on well log correlation and subsurface mapping, sedimentological evidence, and comparison of coeval detrital zircon records from the surrounding area, we conclude that the rising Ouachita orogen to the east provided a majority of Pennsylvanian clastics except for some Early Pennsylvanian clastics to the north, which were likely derived from local uplifts associated with the reactivation of the Southern Oklahoma Aulacogen. Alternative to a trans-continental delivery system, we propose a model of multi-recycling with intermitted contribution from local active tectonic belt to explain the difference and similarity of U-Pb detrital zircon ages of the Pennsylvanian clastics from north-central Texas.