Publications by authors named "Christopher R Fielding"

2 Publications

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

Nat Commun 2019 01 23;10(1):385. Epub 2019 Jan 23.

Isotope Geology Laboratory, Boise State University, 1910 University Drive, Boise, ID, 83725-1535, USA.

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.
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http://dx.doi.org/10.1038/s41467-018-07934-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6344581PMC
January 2019

CO2-forced climate and vegetation instability during Late Paleozoic deglaciation.

Science 2007 Jan;315(5808):87-91

Department of Geology, University of California, Davis, CA 95616, USA.

The late Paleozoic deglaciation is the vegetated Earth's only recorded icehouse-to-greenhouse transition, yet the climate dynamics remain enigmatic. By using the stable isotopic compositions of soil-formed minerals, fossil-plant matter, and shallow-water brachiopods, we estimated atmospheric partial pressure of carbon dioxide (pCO2) and tropical marine surface temperatures during this climate transition. Comparison to southern Gondwanan glacial records documents covariance between inferred shifts in pCO2, temperature, and ice volume consistent with greenhouse gas forcing of climate. Major restructuring of paleotropical flora in western Euramerica occurred in step with climate and pCO2 shifts, illustrating the biotic impact associated with past CO2-forced turnover to a permanent ice-free world.
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http://dx.doi.org/10.1126/science.1134207DOI Listing
January 2007