T98 Earth Life Transitions and Major Continental Biological Events of the Phanerozoic

Monday, 23 October 2017
8:00 AM - 12:00 PM
Room 611

REVISITING EARLY PERMIAN CO2 VIA IMPROVED INPUT PARAMETERS AND MODELS

Paper number: T98-6
Program: Technical Sessions
Time: 9:10 AM – 9:25 AM

Authors

Abstract

The late Paleozoic Ice Age (LPIA; 340–290 Ma) archives repeated major climate changes within an icehouse and is the only record of a permanent turnover from icehouse to fully greenhouse conditions since the evolution of metazoans and vascular plants. In addition, the LPIA has long been compared to the Pleistocene glacial state given that both were characterized by very low atmospheric pCO2, eccentricity-scale glacial-interglacial cycles, and extensive, long-lived continental ice sheets. Existing paleoatmospheric CO2 estimates, based on paleosol carbonates and fossil plant proxy methods, show a linkage between shifts in pCO2, ice volume, and climate that are indicative of greenhouse gas-forcing. Here, focusing on the demise of the LPIA, we reevaluate published latest Pennsylvanian through middle Permian CO2 estimates by applying existing paleosol carbonate data and an improved organic matter data set to the PBUQ model, which fully propagates the uncertainty associated with all input parameters. The updated CO2 estimates are directly compared to plant-based early Permian CO2 values obtained using a mechanistic CO2 model and fossil cuticles collected from the same stratigraphic successions as the pedogenic carbonates. Preliminary reformulated Early Permian CO2 results indicate absolute pCO2 estimates are more than half those previously published (Montañez et al. 2007), and delineate a CO2 rise from a Late Pennsylvanian-earliest Permian nadir to a mid-Permian maximum of ~1400 ppm. In addition, there is good agreement between paleosol-based and stomata-based mechanistic CO2 estimates. These improved data represent an opportunity to understand the evolution of CO2 during the demise of global glaciation, with implications for our current glacial state.

Geological Society of America Abstracts with Programs. Vol. 49, No. 6

doi: 10.1130/abs/2017AM-300828

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