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

拟议的项目是对遥远的东南极洲沙克尔顿山脉的岩石收集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。这一详细的分析将大大提高对该地区的地质认识，并使我们能够评价它在南极洲形成中的作用。25年前，几支欧洲地质学家组成的探险队进行了两次夏季考察，以确定东南极洲沙克尔顿山脉的地质演化，这是一项多国努力。结果令人印象深刻：一幅统一的地质图和来自整个山区的岩石和化石的详尽收集，以及一个突出其复杂历史的分析程序（Tessensohn和Thomson， 1999）。自Euroshack考察以来，地质调查一直有限，最全面的研究由Will等人进行（2009年，2010年）。这项工作强调了沙克尔顿山脉位于地质十字路口：以前的造山事件的痕迹，许多负责地壳单元的缝合和南极东部大陆的组装，要么穿过山脉，要么走向它（图），并证明它和东南极洲是全球古地理重建的关键组成部分（Liu et al., 2018）。自欧洲沙克考察以来进行的遥感和地球物理调查突出表明，该山脉的构造历史是不完整的。有些地区有明显的磁响应，但这些地区的岩石暴露在很大程度上没有得到研究，而其他地区则表明比当前构造模型所显示的更复杂。重要的是，这些独特的地球物理特征显然会持续到东南极洲的内部，这表明对沙克尔顿山脉的地球物理认识的提高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。这位学生在剑桥的英国南极调查局（BAS）工作，他将使用1990年代在BAS保存的具有地球物理特征的岩石标本。利用圣安德鲁斯大学最先进的地球化学和地质年代学设备，将测量谷物的各种同位素组成，各种不同矿物的部分谷物（例如锆石中的U-Pb和Hf同位素），并辅以整个岩石的主要元素和微量元素地球化学。该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事件相关的变质作用和岩浆作用的年龄和条件。该学生将在使用质谱法进行同位素和元素分析方面培养高水平的专业知识。这项工作将与主管Gardiner（圣安德鲁斯），Riley （BAS）和Flowerdew （CASP）密切合作，学生将被嵌入BAS（剑桥）和圣安德鲁斯大学的研究团队中。通过对远离该山脉的地球物理异常的外推，提高了对各种地球物理特征如何发展及其所代表的意义的理解，并将其纳入了东南极洲及其以前邻近地区的综合地质和构造历史。在与Ferraccioli （BAS）的密切合作下，该学生将获得处理和解释航空地球物理数据的强化培训，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（非洲南部）进行比较实地考察的可能性（图）将使人们对元古代序列有更广泛的认识。总的来说，拟议的项目将确定沙克尔顿山脉的地质和构造变质史，并评估其在东南极洲的位置

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