US-Brazil Planning Visit: An Integrated Approach to Resolving the late Paleozoic Ice Age in the Parana Basin, Brazil

美国-巴西计划访问：解决巴西巴拉那盆地晚古生代冰河时代问题的综合方法

• 批准号: 1444210
• 负责人: Isabel Montañez
• 金额: $ 4.45万
• 依托单位: University of California-Davis
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2016-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1444210&HistoricalAwards=false
• 关键词: US; Brazil; Planning; Visit; Integrated

US-Brazil Planning Visit: A Collaborative Effort to Reconstruct the Climate of the Last Icehouse in the Paraná Basin, BrazilPart1: This international collaborative research will revolutionize our ability to correlate geologic, paleoclimate, and biotic events throughout South America and will permit assessment of the degree of global synchroneity of events and the nature of teleconnections in the late Paleozoic climate system. The geochronologic framework we will develop has the potential to also contribute to unraveling the tectonic evolution of the Andes and shedding light on the origin of economic metals and petroleum resources in South America. The long-term international collaboration will facilitate the exchange of scientific and education information and resources by the investigators and provide more diverse training of US and Brazilian undergraduate and graduate students.Part2:The last icehouse on Earth (340 to 260 million years ago), prior to our current glacial world, was the longest lived and most geographically extensive ice age of the past half billion years. Despite substantially different geography than today, the late Paleozoic Ice Age (LPIA) provides insight into the response of icehouse climate processes and the biosphere to major perturbation, including CO2-forcing of climate. The demise of this icehouse records the only transition of a vegetated and metazoan world from a glacial state to fully greenhouse conditions. Studies of the past two decades have raised fundamental questions and defined paradoxes regarding the climate system and climate-life linkages during this time. Resolving these scientific issues requires better time constraints for high-latitude depositional basins that contain a rich record of the LPIA. The Paraná Basin is an ideal natural laboratory as it contains one of the thickest successions of late Paleozoic glacial and post-glacial strata and has long been considered a key geographic piece of the puzzle regarding the nature and timing of glaciation in Gondwana. Widely distributed volcanic ashes offer the potential to develop a U-Pb dated higher latitude record of high temporal resolution and continuity. Sedimentary deposits, which are rich in paleoclimate proxies and characterize the successions above and between glacial deposits provide an opportunity to evaluate, via fossil soil, geochemical and fossil leaf analyses, how the regional climate conditions and paleo-atmospheric CO2 varied between glacial maxima and glacial minima. We are carrying out a planning visit and reconnaissance fieldtrip to initiate an international research and education collaboration with Brazilian investigators at the Universidade Federal do Rio Grande Do Sul (Roberto Iannuzzi) and the Universidade Federal do Paraná (Fernando Farias Vesely). The longer-term collaborative project, which integrates the group?s complimentary scientific interests and expertise, focuses on three research objectives that will improve our understanding of the climate system and climate-life linkages during this last icehouse. These include (1) developing high-precision U-Pb ages for ashes within the Permo-Carboniferous succession of the Paraná Basin, (2) integrating field evidence of the geographic distribution of ice sheets with the U-Pb and Hf isotopic compositions of detrital zircons from glacial deposits in order to reconstruct the ice sheet history in west-central Gondwana, and (3) developing high-resolution climate records for the Paraná Basin & assess their linkages to the glaciation history, Gondwanan paleobotanical records, and existing lower-latitude (paleotropical) proxy records.

美国-巴西计划访问：一个合作的努力，以重建在巴拉那盆地，BrazilPart 1的最后一个冰库的气候：这一国际合作研究将彻底改变我们的能力，在整个南美洲的地质，古气候和生物事件的相关性，并将允许评估事件的全球同步性的程度和晚古生代气候系统的遥相关性的性质。我们将开发的地质年代框架也有可能有助于解开安第斯山脉的构造演化，并揭示南美洲经济金属和石油资源的起源。长期的国际合作将促进科学和教育信息和资源的交流，并为美国和巴西的本科生和研究生提供更多样化的培训。第二部分：地球上最后的冰库（3.4亿至2.6亿年前），在我们现在的冰川世界之前，是过去5亿年中寿命最长、地理范围最广的冰河时代。尽管与今天的地理有很大不同，晚古生代冰河时代（LPIA）提供了对冰库气候过程和生物圈对重大扰动（包括气候的CO2强迫）的响应的见解。这个冰库的消亡记录了植物和后生动物世界从冰川状态到完全温室条件的唯一转变。过去二十年的研究提出了一些基本问题，并界定了这一时期气候系统和气候-生命联系方面的悖论。解决这些科学问题需要更好的时间限制，高纬度沉积盆地，包含丰富的记录的LPIA。巴拉那盆地是一个理想的天然实验室，因为它包含了晚古生代冰川和冰后期地层最厚的继承之一，长期以来一直被认为是冈瓦纳冰川作用的性质和时间的关键地理部分。广泛分布的火山灰提供了开发高时间分辨率和连续性的U-Pb定年高纬度记录的潜力。沉积沉积物，这是丰富的古气候代理和特征的继承以上和冰川沉积物之间提供了一个机会，通过土壤化石，地球化学和化石叶分析，如何区域气候条件和古大气CO2变化之间的冰川最大和冰川最小。我们正在进行一次规划访问和实地考察，与南里奥格兰德联邦大学（Roberto Iannuzzi）和巴拉那联邦大学（Fernando Farias Vesely）的巴西研究人员开展国际研究和教育合作。长期的合作项目，它整合了集团？的互补的科学兴趣和专业知识，侧重于三个研究目标，这将提高我们对气候系统的理解和气候与生命的联系，在这最后的冰库。这些工作包括：（1）建立巴拉那盆地石炭-二叠纪序列中灰烬的高精度U-Pb年龄;（2）将冰盖地理分布的野外证据与冰川沉积物中碎屑锆石的U-Pb和Hf同位素组成相结合，以重建冈瓦纳中西部冰盖的历史;（3）建立巴拉那盆地的高分辨率气候记录，评估其与冰川历史、冈瓦纳古植物记录和现有低纬度（古热带）代用记录的联系。