2 Reconstructing Paleo-Environmental Changes I

Thursday, 28 March 2019
8:00 AM - 12:00 PM
Gold Ballroom

LINKS BETWEEN VOLCANISM AND THE END-PERMIAN MASS EXTINCTION IN SHALLOW MARINE ENVIRONMENTS OF THE NANPANJIANG BASIN, SOUTH CHINA

Paper number: 2-8
Program: Theme Sessions
Time: 10:15 AM – 10:35 AM

Authors

Abstract

Interpretation of the end-Permian mass extinction is complicated by the lack of continuous high-resolution records. The Penglaitan section, located on the northern bank of the Hongshui river near Laibin, Guangxi, China, was deposited in a shallow mixed carbonate-clastic ramp in the Nanpanjiang Basin, in the latest part of the Changhsingian age. The lower Penglaitan section comprises approximately 600 meters of latest Permian strata, which have been dated from 252.4 Ma to 251.9 Ma, yielding a sedimentation rate of roughly 120 cm/kyr. This gives the section greater temporal resolution than the Meishan GSSP section, or any other known PTB section worldwide. This rapid sedimentation rate allows for a more accurate understanding of regional volcanism and other environmental stressors over short time scales. Geochemical data from a core of the Penglaitan section show deviations from a predominant background sediment source, with both mafic and felsic components. These deviations suggest a dynamic and complex local volcanic environment, which may have stressed the environment prior to the main extinction event. Using redox and productivity sensitive elements, as well as stable isotopes of organic material, we attempt to reconstruct biogeochemical and environmental responses to these volcanic events in shallow marine environments of the Nanpanjiang Basin. With the level of stratigraphic detail available for this section, the well-documented collapse in primary productivity in South China can be shown to have occurred in the earliest Triassic, rather than coincident with the PTB. This new section will allow for a more detailed interpretation of events leading up to the end-Permian mass extinction.

Geological Society of America Abstracts with Programs. Vol. 51, No. 3

doi: 10.1130/abs/2019SE-325878

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