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

晚古生代冰期是过去5亿年中寿命最长的冰期，与目前人类进化和生活的冰库有许多相似之处。在古生代冰库(3.4亿至2.9亿年前)期间，大气中的氧和碳水平异常，生命转移到陆地上，第一批林木森林在地球上扩张，大规模野火出现。因此，我们必须对晚古生代地球及其冰川史有一个更全面的了解。巴西巴拉那冰海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、实地考察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，建立一个可输出的、准确的、高精度的年代地层格架，确定该地区前所未有的精度和精度的锆石U-Pb值年龄。这将使现有的冈德瓦南冰川假设得以检验，并将对冰川的同步性程度施加限制，并确定冈瓦那中西部地区冰川末端消融的时间。其次，将通过沉积学和碎屑锆石来源研究开发精细的沉积和冰川模型，并将其整合到高精度的年代地层框架中。这将对流入巴拉那盆地的冰川的时间、来源和地理范围施加数量限制，并允许重建其冰川物质平衡随时间的变化。第三，这项研究将建立大陆气候变率的U-Pb年龄校准的地球化学替代记录，以检验区域气候的重大变化与冰川进退和末期冰川消融同步的假设。该项目将导致对过去从冰室到温室的过渡有一个更全面的了解。

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.