Geodynamic Models of Subsidence and Lithospheric Flexure at the ANDRILL Drill Sites: Implications for Cenozoic Tectonics and Ice Sheet History

智力优势：本研究将把南维多利亚陆盆地的沉降历史置于定量的地球动力学背景下，并将评估与晚新近纪埃里伯斯火山群对地壳的火山负荷相关的挠曲的影响。这将通过扩展南极西部裂谷系统的伸展地球动力学模型来完成，以包括假设发生在晚古近纪和中新世的伸展中断，并通过开发一个新的火山负荷和相关岩石圈弯曲的地球动力学模型。将使用有限元和有限差分建模方法。在项目的第一阶段，将开发一系列的伸展地球动力学模型，以检查所提出的伸展中断对伸展风格的影响，重点是建立一个基于裂谷风格变化的过程的理解，从晚白垩纪的扩散到新生代的更集中。这些模型将检验伸展断裂导致裂谷样式变化的假设，并将对断裂的时间和持续时间进行限制。该项目的第二阶段将利用先前模型的热学和流变特性来限制岩石圈的弯曲刚度，以便模拟火山载荷下的弯曲响应，以测试弯曲沉降导致ANDRILL and - 1a站点地面冰和浮冰之间循环变化的假设，使该核心的气候记录的解释复杂化，以及弯曲有助于and - 2b站点的应力方向。这与预期的区域拉应力取向不一致。更广泛的影响：该项目将培养一名本科生和一名硕士研究生。拓展活动包括计划在地区高中、初级学院和有地质学课程的四年制大学举行的一系列讲座。

Intellectual Merit: This research will place the subsidence history of the southern Victoria Land Basin into a quantitative geodynamic context and will assess the influence of flexure associated with late Neogene volcanic loading of the crust by the Erebus Volcanic Group. This will be done by extending geodynamic models of extension in the West Antarctic Rift System to include extensional hiatuses hypothesized to have occurred during the Late Paleogene and Miocene, and by developing a new geodynamic model of volcanic loading and associated lithosphere flexure. Finite element and finite difference modeling methods will be used. In the first phase of the project, a series of extensional geodynamic models will be developed to examine the effect that proposed extensional hiatuses have on the style of extension, with emphasis placed on developing a process based understanding of the change in rift style from diffuse during the Late Cretaceous to more focused during the Cenozoic. The models will test the hypotheses that extensional hiatuses led to the change in rifting style, and will place constraints on the timing and duration of the hiatuses. The second phase of the project will use the thermal and rheological properties of the previous models to constrain the flexural rigidity of the lithosphere in order to model the flexural response to volcanic loading to test the hypotheses that flexural subsidence contributed to cyclic changes between grounded and floating ice at the ANDRILL AND-1A site, complicating interpretations of the climatic record from this core, and that flexure contributes to the stress orientation at the AND-2B site, which is inconsistent with the expected regional extensional stress orientation.Broader impacts: The project will train an undergraduate student and an M.S. student. Outreach activities include a planned series of talks at regional high schools, junior colleges, and 4-year colleges that have geology programs.