Anomalously diverse Early Triassic ichnofossil assemblages in northwest Pangea: A case for a shallow-marine habitable zone

Early Triassic trace fossil assemblages from the northwest margin of Pangea record a diverse suite of postextinction infauna. These ichnofossil assemblages occurred within well-oxygenated, shallow-marine refuges in a Panthalassa Ocean otherwise characterized by widespread anoxia. We propose an environmentally controlled model for their distribution, in which wave aeration, enhanced by frequent storms, gave rise to an optimal zone for benthic colonization. Within this habitable zone extinction pressures were ameliorated and postextinction recovery duration was minimized.

[1]  A. Baud,et al.  Correlation of the Permian-Triassic Boundary in Arctic Canada and Comparison with Meishan, China , 2020, Stratigraphy.

[2]  A. Knoll,et al.  Paleophysiology and End-Permian Mass Extinction , 2007 .

[3]  R. Summons,et al.  Evidence for photic zone euxinia through the end-Permian mass extinction in the Panthalassic Ocean (Peace River Basin, Western Canada) , 2007 .

[4]  R. MacNaughton,et al.  Palynostratigraphy, Lithostratigraphy and Thermal Maturity of the Lower Triassic Toad and Grayling, and Montney Formations of Western Canada, and Comparisons with Coeval Rocks of the Sverdrup Basin, Nunavut , 2005 .

[5]  D. Bottjer,et al.  Early Triassic Trace Fossils of the Western United States and their Implications for Prolonged Environmental Stress from the End-Permian Mass Extinction , 2004 .

[6]  R. Twitchett,et al.  Rapid and synchronous collapse of marine and terrestrial ecosystems during the end-Permian biotic crisis , 2001 .

[7]  D. Erwin.  Lessons from the past: Biotic recoveries from mass extinctions , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[8]  R. Twitchett.  Palaeoenvironments and faunal recovery after the end-Permian mass extinction , 1999 .

[9]  D. Lehrmann.  Early Triassic calcimicrobial mounds and biostromes of the Nanpanjiang Basin , 1999 .

[10]  P. Wignall,et al.  The Permo-Triassic transition in Spitsbergen: δ13Corg chemostratigraphy, Fe and S geochemistry, facies, fauna and trace fossils , 1998, Geological Magazine.

[11]  C. Henderson.  Uppermost Permian Conodonts and the Permian-Triassic Boundary in the Western Canada Sedimentary Basin , 1997 .

[12]  M. F. Miller,et al.  A semiquantitative field method for evaluating bioturbation on bedding planes , 1997 .

[13]  Isozaki,et al.  Permo-Triassic Boundary Superanoxia and Stratified Superocean: Records from Lost Deep Sea , 1997, Science.

[14]  R. Twitchett,et al.  Trace fossils and the aftermath of the Permo-Triassic mass extinction: evidence from northern Italy , 1996 .

[15]  R. Twitchett,et al.  Oceanic Anoxia and the End Permian Mass Extinction , 1996, Science.

[16]  R. Rosenberg,et al.  Marine benthic hypoxia: a review of its ecological effects and the behavioural responses of benthic macrofauna , 1995 .

[17]  C. Scotese,et al.  Phanerozoic Paleogeographic and Paleoclimatic Modeling Maps , 1994 .

[18]  Hubert Chanson,et al.  EFFECTS OF PLUNGING BREAKERS ON THE GAS CONTENTS IN THE OCEAN , 1994 .

[19]  D. Erwin.  The Terminal P-Tr Events. (Book Reviews: The Great Paleozoic Crisis. Life and Death in the Permian.) , 1993 .

[20]  P. Wignall,et al.  Anoxia as a cause of the Permian/Triassic mass extinction : facies evidence from northern Italy and the western United States , 1992 .

[21]  D. Wallace,et al.  Large air–sea gas fluxes associated with breaking waves , 1992, Nature.

[22]  K. Föllmi,et al.  Doomed pioneers: Gravity-flow deposition and bioturbation in marine oxygen-deficient environments , 1990 .

[23]  Mary L. Droser,et al.  A semiquantitative field classification of ichnofabric , 1986 .

[24]  A. Embry.  Stratigraphic Subdivision of the Blind Fiord and Bjorne Formations [Lower Triassic], Sverdrup Basin, Arctic Islands , 1986 .

[25]  A. Ekdale,et al.  Chondrites: A Trace Fossil Indicator of Anoxia in Sediments , 1984, Science.

[26]  D. Bottjer,et al.  Tiering in Suspension-Feeding Communities on Soft Substrata Throughout the Phanerozoic , 1982, Science.

[27]  J. D. Howard.  Trace Fossils as Criteria for Recognizing Shorelines in Stratigraphic Record: ABSTRACT , 1969 .