The Shackleton Range of East Antarctica: unravelling a complex geological history via an integrated geochronological, geochemical and geophysical appr

南极洲东部的沙克尔顿山脉：通过综合地质年代学、地球化学和地球物理方法揭示复杂的地质历史

• 批准号: 2881843
• 金额: --
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2881843
• 关键词: Shackleton; Range; East; Antarctica; unravelling

The proposed project is a multidisciplinary geochemical, geochronological and geophysical study on rock collections and aeromagnetic data from the remote Shackleton Range of East Antarctica. This detailed analysis will substantially improve the geological understanding of the region and allow us to evaluate its role in the assembly of Antarctica.A multi-national effort to determine the geological evolution of the Shackleton Range in East Antarctica was conducted over 25 years ago during two summer expeditions involving several teams of European geologists (Euroshack Expedition). The result was impressive: a unified geology map and an exhaustive collection of rocks and fossils from across the mountainous region, and an analytical programme highlighting its complex history (Tessensohn and Thomson, 1999).Geological investigations since the Euroshack expedition have been limited, with the most comprehensive studies carried out by Will et al. (2009, 2010). This work has highlighted that the Shackleton Range is situated at a geological crossroads: traces of former mountain building events, many responsible for the suturing of crustal units and the assembly of the East Antarctic continent, either cross the Range or trend toward it (Figure) and have demonstrated that it and East Antarctica form key components in global paleogeographic reconstructions (Liu et al., 2018).Remote sensing and geophysical surveys conducted since the Euroshack expedition have highlighted evidence that the tectonic history for the Range is incomplete. Some areas have distinct magnetic responses yet rock exposures from these regions are largely unstudied, whereas other areas indicate a greater complexity than current tectonic models suggest. Importantly these unique geophysical signatures apparently continue into the interior of East Antarctic, indicating that an improved geophysical understanding of the Shackleton Range would help underpin a more comprehensive tectonic framework for East Antarctica within the context of supercontinent reconstruction.The student, based at the British Antarctic Survey (BAS) in Cambridge, will use the 1990's rock collection of the geophysically distinctive units held at BAS. Using the state of the art geochemistry and geochronology facilities at St Andrews University, a diverse set of isotopic compositions will be measured on grains, portions of grains for a variety of different minerals (e.g. U-Pb and Hf isotopes in zircon) and supplemented by whole-rock major and trace elements geochemistry. The student will use these data to update the geological evolution of the Shackleton Range, focussing on constraining the age and conditions of metamorphism and magmatism associated with the former mountain building events. The student will develop a high level of expertise in the use of mass spectrometry for isotopic and elemental analysis. This work will be carried out in close collaboration with the supervisors Gardiner (St Andrews), Riley (BAS) and Flowerdew (CASP) and the student will be embedded in research teams at both BAS (Cambridge) and St Andrews University.The improved understanding of how the various geophysical signatures developed and what they represent, contextualised into a comprehensive geological and tectonic history for East Antarctica and formerly adjacent regions, by the extrapolation of the geophysical anomalies away from the Range. In close collaboration with Ferraccioli (BAS), the student will be provided with enhanced training in the processing and interpretation of airborne geophysical data to evaluate the broader tectonic setting of the Shackleton Range. A possibility of comparative fieldwork in either the Gawler craton (Australia) or Kalahari craton (southern Africa) (Figure) will enable a broader view of the Proterozoic sequences.Overall the proposed project will determine a geological and tectono-metamorphic history of the Shackleton Range and evaluate its place in the assembly of East Antarctica

拟议的项目是对东南极洲沙克尔顿山脉偏远地区的岩石收藏和航磁数据进行多学科的地球化学、地质年代学和地球物理研究。这种详细的分析将大大提高对该地区地质的了解，并使我们能够评估其在南极洲组装中的作用。25年前，在两次夏季探险期间，多国进行了确定东南极洲沙克尔顿山脉地质演变的努力，涉及多个欧洲地质学家团队（Euroshack Expedition）。结果令人印象深刻：统一的地质图和来自整个山区的岩石和化石的详尽收集，以及强调其复杂历史的分析方案（Tessensohn和Thomson，1999）。自Euroshack探险以来的地质调查有限，Will等人进行了最全面的研究（2009，2010）。这项工作强调了沙克尔顿山脉位于地质十字路口：以前的山脉建设事件的痕迹，许多负责地壳单位的迁移和东南极大陆的组装，要么穿过山脉，要么走向它（图），并证明它和东南极洲形成全球古地理重建的关键组成部分（Liu等人，2018).自Euroshack探险以来进行的遥感和地球物理调查突出了山脉构造历史不完整的证据。一些地区有不同的磁响应，但这些地区的岩石暴露在很大程度上是未经研究的，而其他地区表明比目前的构造模型所建议的更复杂。重要的是，这些独特的地球物理特征显然一直延续到东南极洲的内部，这表明对沙克尔顿山脉的更好的地球物理理解将有助于在超大陆重建的背景下为东南极洲建立一个更全面的构造框架。这位来自剑桥英国南极调查局（BAS）的学生说，将使用20世纪90年代的岩石收集的岩石独特的单位举行的BAS。利用圣安德鲁斯大学最先进的地球化学和地质年代学设施，将对各种矿物的颗粒、颗粒部分（例如锆石中的U-Pb和Hf同位素）测量一套不同的同位素组成，并辅之以全岩主要和微量元素地球化学。学生将使用这些数据来更新沙克尔顿山脉的地质演化，重点是限制与前造山活动相关的变质作用和岩浆作用的年龄和条件。学生将在同位素和元素分析中使用质谱法方面发展高水平的专业知识。这项工作将与主管加德纳密切合作进行（圣安德鲁斯），莱利（BAS）和Flowerdew（CASP）和学生将嵌入在BAS的研究团队（剑桥）和圣安德鲁斯大学。对各种地球物理特征如何发展及其所代表的意义的进一步理解，结合东南极洲和以前邻近地区的全面地质和构造历史，根据山脉外的地球物理异常推断与Ferraccioli（BAS）密切合作，学生将获得航空地球物理数据处理和解释方面的强化培训，以评估沙克尔顿山脉更广泛的构造环境。在高勒克拉通（澳大利亚）或卡拉哈里克拉通（南部非洲）（图）进行比较野外工作的可能性将使对元古宙层序有更广泛的了解。总体而言，拟议的项目将确定沙克尔顿山脉的地质和构造变质历史，并评估其在东南极洲组合中的地位