title: Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms.
abstract: New high-resolution U-Pb dates indicate a duration of 89 ± 38 kyr for the Permian hiatus and of 14 ± 57 kyr for the overlying Triassic microbial limestone in shallow water settings of the Nanpanjiang Basin, South China. The age and duration of the hiatus coincides with the Permian-Triassic boundary (PTB) and the extinction interval in the Meishan Global Stratotype Section and Point, and strongly supports a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate as indicated by terrestrial plants. Our model of the Permian-Triassic boundary mass extinction (PTBME) hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO2induced a transient cool climate whose early phase saw the deposition of the microbial limestone.
authors.affiliation: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland.
authors.forename: Björn
authors.initials: B
authors.lastname: Baresel
authors.affiliation: Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland.
authors.forename: Hugo
authors.initials: H
authors.lastname: Bucher
authors.affiliation: Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland.
authors.forename: Borhan
authors.initials: B
authors.lastname: Bagherpour
authors.affiliation: Paleontological Institute and Museum, University of Zurich, Karl Schmid-Strasse 4, 8006 Zurich, Switzerland.
authors.forename: Morgane
authors.initials: M
authors.lastname: Brosse
authors.affiliation: Guangxi Bureau of Geology and Mineral Resources, Jiangzheng Road 1, 530023 Nanning, China.
authors.forename: Kuang
authors.initials: K
authors.lastname: Guodun
authors.affiliation: Department of Earth Sciences, University of Geneva, Rue des Maraîchers 13, 1205 Geneva, Switzerland.
authors.forename: Urs
authors.initials: U
authors.lastname: Schaltegger
mesh_terms: D002681:China; D004783:Environmental Microbiology; D053476:Extinction, Biological