Thermochronologic Constraints on the Formation of the Transantarctic Mountains, Antarctica

9315831菲茨杰拉德该奖项支持使用裂变径迹和40Ar/39Ar热年代学研究横贯北极山脉的沙克尔顿冰川地区的热演化。目标是利用岩石的热历史(温度-时间数据，确定冷却时间)来推断该地区抬升和剥蚀的时间和速度。这些信息反过来将允许对罗斯湾西南边缘山脉隆起的机械模型进行约束。该奖项的第一年将用于分析现有藏品中的岩石，并为第二年的实地工作做准备。沙克尔顿冰川地区是新野外工作的焦点，因为它代表了横贯北极山脉的两段之间的一个实质性的地壳块体，这两段山脉已经得到了广泛的研究。采样策略是在横跨南极山脉并沿其长度定期收集基岩的垂直剖面。这一策略最大限度地减少了因区域中未映射的断层而导致的复杂和模糊的可能性，并最大限度地提高了对冷却历史进行良好估计的可能性。这项新的实地工作将检验横贯北极山脉是分段的假设，每个分段都有不同的隆升历史。每条垂直剖面的冷却时间数据是该地区地质发展的基本信息。这些数据将被用来推断每个地方的抬升和剥蚀历史。出现的地理模式将有助于限制横贯北极山脉中部的构造演化，它们将对从冈瓦纳分裂和罗斯湾的发展到南极洲新生代冰盖发展的各种地质问题施加限制。***

9315831 Fitzgerald This award supports a study of the thermal evolution of the Shackleton Glacier region of the Transantarctic Mountains using fission track and 40Ar/39Ar thermochronology. The goal is to use the thermal history of the rocks (temperature-time data that dates the time of cooling) to infer the timing and rate of uplift and denudation of the region. This information will, in turn, allow constraints on mechanistic models for uplift of the range on the southwestern edge of the Ross Embayment. The first year of the award will be used to analyze rocks from existing collections and to prepare for field work in the second year. The Shackleton Glacier region is the focus of new field work because it represents a substantial crustal block that is between two segments of the Transantarctic Mountains which have already been extensively studied. The sampling strategy is to collect vertical profiles from basement rocks at regular intervals across, and along the length of, the Transantarctic Mountains. This strategy minimizes the potential for complications and ambiguities which can result from unmapped faults in the region and maximizes the potential for a good estimate of the cooling history. This new field work will test the hypothesis that the Transantarctic Mountains is segmented, with each segment having a distinct uplift history. The data on the time of cooling at each of several vertical profiles is basic information on the geologic development of the region. These data will be used to infer the uplift and denudation history for each locality. The geographic patterns that emerge will help to constrain the tectonic evolution of the central Transantarctic Mountains and they will place constraints on a diversity of geologic problems from Gondwana breakup and development of the Ross Embayment to development of the Cenozoic ice sheets of Antarctica. ***