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: 1444181
• 负责人: John Isbell
• 金额: $ 3.07万
• 依托单位: University of Wisconsin-Milwaukee
• 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 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1444181&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：重建巴西帕拉南<e:1>盆地最后一个冰窖气候的合作努力第一部分：这项国际合作研究将彻底改变我们将整个南美洲的地质、古气候和生物事件联系起来的能力，并将允许评估事件的全球同步程度和晚古生代气候系统中遥相关的性质。我们将开发的地质年代学框架也有可能有助于揭示安第斯山脉的构造演化，并阐明南美洲经济金属和石油资源的起源。这项长期的国际合作将促进科研人员交流科学和教育信息和资源，并为美国和巴西的本科生和研究生提供更多样化的培训。在我们现在的冰川世界之前，地球上最后一个冰窖（3.4亿到2.6亿年前）是过去5亿年来持续时间最长、地理范围最广的冰期。尽管地理位置与今天有很大的不同，但晚古生代冰期（LPIA）提供了对冰库气候过程和生物圈对主要扰动（包括二氧化碳强迫气候）的响应的深入了解。这个冰窖的消亡记录了一个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，并确定了这段时间内气候系统和气候-生命联系的悖论。要解决这些科学问题，需要对高纬度沉积盆地进行更好的时间限制，因为高纬度沉积盆地含有丰富的lbia记录。帕拉纳<e:1>盆地是一个理想的自然实验室，因为它包含了最厚的晚古生代冰川和后冰川地层序列之一，长期以来一直被认为是冈瓦纳冰川性质和时间之谜的关键地理部分。广泛分布的火山灰提供了发展高时间分辨率和连续性的U-Pb定年高纬度记录的潜力。沉积沉积物具有丰富的古气候代用物，表征了冰川沉积之上和冰川沉积之间的演替特征，通过化石土壤、地球化学和化石叶片分析，可以评估区域气候条件和古大气CO2在冰川极大期和冰川极小期之间的变化。我们正在与巴西南巴西联邦大学（Roberto Iannuzzi）和帕拉纳邦联邦大学<e:1> (Fernando Farias Vesely)的研究人员开展计划访问和实地考察，以启动一项国际研究和教育合作。长期的合作项目，将整个团队整合在一起？我们的科学兴趣和专业知识，集中在三个研究目标上，这将提高我们对最后一个冰窖期间气候系统和气候-生命联系的理解。这些工作包括(1)对帕拉纳<e:1>盆地二叠纪-石炭纪演替中的灰烬进行高精度U-Pb年龄测定；(2)将冰原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，以重建冈瓦纳盆地中西部的冰原历史；(3)为帕拉纳<e:1>盆地建立高分辨率气候记录，并评估其与冰川历史的联系。冈瓦纳古植物学记录，以及已有的低纬度（古热带）代用记录。