Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis

Robert S Nicoll,Chris Mays,Vivi Vajda,Christopher R Fielding,Arne Winguth,James L Crowley,Malcolm Bocking,Tracy D Frank,Stephen Mcloughlin,Cornelia Winguth,Allen P Tevyaw

doi:10.1038/s41467-018-07934-z

Abstract

Past studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes. Here we use palynology coupled with high-precision CA-ID-TIMS dating of euhedral zircons from continental sequences of the Sydney Basin, Australia, to show that the collapse of the austral Permian Glossopteris flora occurred prior to 252.3 Ma (~370 kyrs before the main marine extinction). Weathering proxies indicate that floristic changes occurred during a brief climate perturbation in a regional alluvial landscape that otherwise experienced insubstantial change in fluvial style, insignificant reorganization of the depositional surface, and no abrupt aridification. Palaeoclimate modelling suggests a moderate shift to warmer summer temperatures and amplified seasonality in temperature across the EPE, and warmer and wetter conditions for all seasons into the Early Triassic. The terrestrial EPE and a succeeding peak in Ni concentration in the Sydney Basin correlate, respectively, to the onset of the primary extrusive and intrusive phases of the Siberian Traps Large Igneous Province.

Highlights

Past studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes
The Late Permian to Early Triassic was marked by major perturbations to the Earth system, including the largest mass extinction of the geological record[1,2]
Geochemical proxy records reveal an Earth system susceptible to perturbation by abrupt events that may have included outgassing from the Siberian Trap Large Igneous Province (LIP)[3,4,5] and fly ash emission from intrusions into the West Siberian Coal Basin[6,7]

Summary

Results and Discussion

We document a reference section for the long-term patterns of sedimentological, isotopic, floristic, and environmental change through the Lopingian and Lower Triassic succession based on the fully cored borehole Pacific Power Hawkesbury Bunnerong DDH1 (PHKB1), drilled in the synclinal axis of the Sydney Basin near the Port of Botany, Sydney (Fig. 1). Based, cross-bedded sandstone bodies of coastal plain fluvial channel origin become successively more abundant upward from about the middle of the Illawarra Coal Measures, interbedded with coal seams interpreted as the record of coastal plain mires (Fig. 2). These strata are typified by rich assemblages of Glossopteris leaves in finely laminated facies and by Vertebraria (glossopterid) roots in immature palaeosols.

C Md Ht Sa

10 CAPE HORN

Methods