Collaborative Research: Understanding the Late Paleozoic Icehouse from a Southern Hemisphere (Paranaì Basin, Brazil) paleo-perspective

点击翻译按钮获取中文摘要

The late Paleozoic Ice Age is the longest-lived glacial interval of the past half billion years, sharing many parallels with the current icehouse in which humans evolved and live. During the Paleozoic icehouse (340 to 290 million years ago) atmospheric oxygen and carbon levels were anomalous, life moved onto land, the first wooded forests expanded across the Earth, and large-scale wildfires emerged. Thus, it is important that we develop a more complete understanding of the late Paleozoic Earth and its dynamic glaciation history. The glacial-marine Parana Basin, Brazil provides an ideal opportunity for this work and the project will include training for U.S. and Brazilian students through seminars, field and lab work, and exchange visits.This research will address three research objectives. First, an exportable, accurate and high-precision chronostratigraphic framework will be built by defining U-Pb zircon ages of unprecedented precision and accuracy for this region. This will permit testing of existing hypotheses of Gondwanan glaciation and will place constraints on the degree of synchronicity of the glaciations and establish the timing of terminal deglaciation in west-central Gondwana. Second, refined depositional and glaciation models will be developed through sedimentologic and detrital zircon provenance studies, integrated into the high-precision chronostratigraphic framework. This will place quantitative constraints on the timing, source, and geographic extent of glaciers feeding into the Parana Basin and permit reconstruction of changes in their glacial mass balance through time. Third, this research will develop U-Pb age-calibrated geochemical proxy records of continental climate variability that will test the hypothesis that major shifts in regional climate occurred in-step with periods of glacier advance/retreat and terminal deglaciation. This project will lead to a more complete understanding of icehouse to greenhouse transitions of the past.