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

晚古生代冰河时代是过去5亿年中最长的冰河时期，与人类进化和生活的冰窖有许多相似之处。在古生代冰库时期（3.4亿至2.9亿年前），大气中的氧和碳含量异常，生命转移到陆地上，第一批树木繁茂的森林在地球上扩张，大规模的野火出现。 因此，重要的是，我们开发一个更完整的了解晚古生代地球及其动态冰川的历史。巴西的巴拉那冰川海洋盆地为这项工作提供了一个理想的机会，该项目将包括通过研讨会、实地和实验室工作以及交流访问对美国和巴西学生进行培训。首先，通过对该地区前所未有的精确和准确的锆石U-Pb年龄的确定，建立一个可输出的、精确的、高精度的年代地层格架。这将允许测试现有的冈瓦纳冰川作用的假设，并将限制冰川作用的同步性程度，并建立在中西部冈瓦纳终端冰川消退的时间。第二，将通过沉积学和碎屑锆石来源研究，建立完善的沉积和冰川作用模型，并将其纳入高精度年代地层框架。这将对流入巴拉那盆地的冰川的时间、来源和地理范围进行定量限制，并允许重建冰川物质平衡随时间的变化。第三，这项研究将开发U-Pb年龄校准的地球化学代用记录大陆气候的变化，将测试的假设，在区域气候的重大变化发生在冰川前进/后退和终端冰川消退的阶段。该项目将导致对过去冰室到温室过渡的更完整的理解。

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.