Collaborative Research: Permian and Triassic Icehouse to Greenhouse Paleoenvironments and Paleobotany in the Shackleton Glacier Area, Antarctica

该合作项目的重点是收集南极洲沙克尔顿冰川(SHK)地区岩石中的植物化石、木材以及沉积和化学信息。这些信息将被用来重建南极洲二叠纪和三叠纪(约2.95亿-2.05亿年前)的植物生命和环境。这一时间间隔具有重要的研究意义，因为南极洲在二叠纪经历了一次大冰川，随后经历了冰川消退和动植物生命的恢复，但在二叠纪末期却遭受了地球历史上最大规模的灭绝。灭绝事件之后，南极洲的气候继续广泛变暖，靠近古南极的地方有森林生长。这些古老的环境为研究气候变化对植物生命的影响提供了一个天然的实验室。该项目的成果将在全球变冷和变暖期间的沉积模式变化领域以及冰川后和全球变暖期间的植物进化领域取得进展。该项目将研究SHK地区冈瓦纳冰川的范围、冰川消退后生命的入侵和随后的繁盛，以及晚二叠世物种灭绝事件后植物生命的最终恢复。只有在南极洲，这种气候和生物转变才会发生从极地到近极的完全演替。SHK地区是一个重要的地区，因为它是世界上为数不多的二叠系-三叠系界线(PTB)暴露在陆相岩石中的地区之一。该项目的野外和实验室工作围绕着三个假说来组织，这些假说解决了地球历史上的基本问题，包括二叠纪到晚古生代冰期期间植物群范围和多样性的变化，PTB可能的历时性，以及早三叠世糟糕的化石保存给人一种错误的印象，即南极洲在这段时间里没有植物。这些假说将通过将各种类型的古植物学方法与详细的沉积学、地层学和地球化学相结合来检验。将从定量和定性两方面收集压缩植物群和石化木材(受地层学限制)，以获得生物多样性和丰度数据，并作为古生态分析的数据源。将进行标准的沉积学和地层学分析，以及古土壤分析，包括矿物学和常量元素和微量元素地球化学。还将收集U-Pb锆石年代学，以更好地约束地质和生物事件随时间的推移。该项目的成果将纳入旨在让妇女和代表性不足的群体参与南极地球科学和古生物学兴奋的教育和外联活动，包括在堪萨斯州和威斯康星州举办的讲习班，以及在实地考察期间与科学课程的链接。

The focus of this collaborative project is to collect fossil plants, wood, and sedimentary and chemical information from rocks in the Shackleton Glacier (SHK) area of Antarctica. This information will be used to reconstruct plant life and environments during the Permian and Triassic (~295-205 million years ago) in Antarctica. This time interval is important to study as Antarctica experienced a large glaciation in the Permian followed by deglaciation and recovery of plant and animal life, only to be subjected to the largest extinction in Earth history at the end of the Permian. After the extinction events, the climate in Antarctica continued to warm extensively and there were forests growing close to the paleo-South Pole. These ancient environments provide a natural laboratory in which to study the effects of climate change on plant life. The results of this project will advance the field in the areas of changing sedimentary patterns during global cooling and warming, as well as plant evolution during times following glaciation and during global warmth. This project will study the extent of the Gondwana glaciation in the SHK area, the invasion and subsequent flourishing of life following glacial retreat, and the eventual recovery of plant life after Late Permian extinction events. Only in Antarctica does a complete polar-to-near-polar succession occur across this climatic and biologic transition. The SHK area is an important one as it is one of the few regions in the world where the Permian-Triassic boundary (PTB) is exposed within terrestrial rocks. The field and lab work for this project is organized around three hypotheses that address fundamental issues in Earth history, including changes in the extent and diversity of flora during the Permian build up to the Late Paleozoic Ice Age, the possible diachronous nature of the PTB, and that poor fossil preservation during the Early Triassic has given a false impression that Antarctica was devoid of plants during this time. The hypotheses will be tested by integrating various types of paleobotanical approaches with detailed sedimentology, stratigraphy, and geochemistry. Compression floras and petrified wood will be collected (constrained by stratigraphy) both quantitatively and qualitatively in order to obtain biodiversity and abundance data, and as a data source for paleoecological analysis. Standard sedimentologic and stratigraphic analyses will be performed, as well as paleosol analyses, including mineralogic and major- and trace-element geochemistry. Collections will also be made for U-Pb zircon geochronology to better constrain geologic and biotic events through time. Results of the project will be incorporated into educational and outreach activities that are designed to include women and under-represented groups in the excitement of Antarctic earth sciences and paleontology, including workshops in Kansas and Wisconsin, as well as links to science classes during fieldwork.