The Buday’ah Formation, Sultanate of Oman: A Middle Permian to Early Triassic oceanic record of the Neotethys and the late Induan microsphere bloom |
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Authors: | Aymon Baud Sylvain RichozBenoit Beauchamp Fabrice CordeyStephen Grasby Charles M HendersonLeopold Krystyn Alda Nicora |
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Institution: | a BGC, Rouvraie 28, CH-1018 Lausanne, Switzerland b Commission for the Palaeontological and Stratigraphical Research of Austria, Austrian Academyrs of Sciences c/o Institute of Earth Sciences, University of Graz, Heinrichstraße 26, 8010 Graz, Austria c Department of Geoscience, University of Calgary, 2500 University Drive, N.W.Calgary, Alberta, Canada T2N 1N4 d Département Sciences de la Terre, CNRS UMR 5125 Paléoenvironnements Paléobiosphère, Université Lyon 1, 69622 Villeurbanne, France e Geological Survey of Canada - Calgary, 3303 33rd Street, N.W. Calgary, Alberta, Canada T2L 2A7 f Department of Palaeontology, Vienna University, Althanstrasse 14, 1090 Vienna, Austria g Dipartimento di Scienze della Terra, Universita degli Studi di Milano, Via Mangiagalli 34, Milano 20133, Italy |
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Abstract: | The Middle Permian to Lower Triassic Buday’ah section, exposed in the Oman Mountains, is the first deep-sea section to be described in the Neotethys. The oceanic sediments were deposited along the southern Tethys margin in the newly formed Hawasina Basin. It is one of the few places where true Tethyan Permian radiolarites are exposed that allow the documentation of CCD evolution through time. The succession begins as oceanic crust pillow basalt with red ammonoid-rich pelagic limestone occurring both above and within inter-pillow cavities; the new occurrence of Clarkina postbitteri hongshuiensis indicates a late Capitanian age for the carbonate. The sharp change to overlying late Capitanian to Changhsingian radiolarite reflects rapid subsidence about 10 Myrs after initial continental breakup that resulted in the formation of the Neotethys Ocean. New conodonts indicate that the Permian-Triassic boundary succession occurs in the first platy lime mudstone beds above a Changhsingian siliceous to calcareous shale unit. The platy lime mudstone beds include an Upper Griesbachian bloom of calcite filled spheres (radiolarians?) that marks a potential world-wide event. New conodonts indicate an early Olenekian age for overlying grey papery limestone that are devoid of both macrofossils and trace fossils indicating that recovery from the Late Permian extinction has not yet progressed within this deep-water environment.δ13Corg, isotope values have not been disturbed and they show a negative shift just below the Permian-Triassic transition and a second one at the parvus zone level above. The Buday’ah succession may represent the most distal and probably deepest Permian and Lower Triassic depositional sequence within the basin. |
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Keywords: | Permian Lower Triassic Chert Radiolaria Conodonts Chemostratigraphy Platy and papery limestone |
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