'COLLABORATIVE RESEARCH: Understanding Climate Change During the Final Stages of Late Paleozoic Gondwanan Glaciation - An Integrated Data-Model Study'

ABSTRACT

COLLABORATIVE RESEARCH: UNDERSTANDING CLIMATE CHANGE DURING THE FINAL STAGES OF LATE

PALEOZOIC GONDWANAN GLACIATION - AN INTEGRATED DATA-MODEL STUDY

Isabel Montanez, University of California, Davis

Vladimir Davydov & Mark Schmitz, Boise State University

Chris Poulsen, University of Michigan

Neil Tabor, Southern Methodist University

Recently developed paleoclimate archives reveal a much more dynamic transition from the late

Paleozoic Gondwanan ice age to a greenhouse world than previously considered - one characterized by

considerable co-variability in climate and pCO2. Recently documented short-lived (1 to 4 m.y.) episodes

of glaciation appear to coincide with large magnitude shifts in atmospheric pCO2, marine and continental

temperatures and relative sea-level suggesting a CO2-climate-glaciation link. This link, however, remains

untested. We propose an interdisciplinary study focused on significantly improving our understanding of

the evolution of the late Paleozoic climate system, and the mechanisms that triggered climate change

during the Earth's last period of transition from icehouse to greenhouse states. The research is designed to

test two hypotheses: (1) that atmospheric CO2 variability was the primary driver for repeated growth and

retreat of continental ice sheets, and, in turn, (2) that late Paleozoic ice sheets strongly influenced global

climate, particularly in the tropics. Specific basins in central and eastern Europe and western Argentina

have been targeted given their stratigraphic and paleogeographic coverage, presence of marine, paralic

and paleosol-bearing terrestrial deposits, and their existing biostratigraphy and potential for further

radiometric dating (i.e., multiple intercalated volcanic tuffs) and biostratigraphic analysis. This research

has three major objectives:

* To establish a radiometrically calibrated, chronostratigraphic framework (Gzhelian to early Middle

Permian) through the integration of new and existing bio-, cyclo-, and chemo-stratigraphic (87Sr/86Sr)

data with U/Pb dating of volcanic tuffs, and the application of these integrated data to multiple

quantitative tools (CONOP, RASC, CASP, GraphCor).

* To further develop and calibrate high-resolution, quantitative proxy records of paleo-atmospheric

pCO2, paleo-precipitation, and marine and terrestrial paleo-temperatures. This includes critical

evaluation and further development of new quantitative proxies as well as direct comparison of proxy

records to sedimentologic evidence for glaciations and 'warmings' in southern Gondwanan

successions.

* Development of a theoretical climate framework for the late Paleozoic glacial-interglacial oscillations

using three-dimensional climate models to quantify the sensitivity of ice sheets on Gondwana to

pCO2, determine the role of ice sheets in driving global climate change, and make climate predictions

that can be tested through comparison with the proxy records.

Broader Impacts: The proposed research will offer four major contributions to the broader scientific

community: (1) a reconstruction of the late Paleozoic climate system at an unprecedented level of

resolution and accuracy, (2) an important test of the pCO2-climate paradigm for climate evolution through

Earth history, (3) documentation of marine-terrestrial climate linkages at unprecedented temporal

resolution for the Paleozoic, and (4) the first test of proposed correlations of cyclothemic successions in

eastern Euramerican and North American basins, and of linkages to the Gondwanan glaciosedimentary

record. In addition, to the planned cross-disciplinary training of undergraduate and graduate students, the

PIs will integrate their research efforts into three educational outreach programs designed to enhance the

research and teaching opportunities of underrepresented undergraduate students and high school science

teachers. We will make our data and model simulations available to the greater scientific community by

importing them into the CHRONOS System (and its partner website, PaleoStrat), a web-based interactive

resource with which PI Davydov is directly involved.