COLLABORATIVE RESEARCH: Using plate circuits to constrain motion between East and West Antarctica

这项提案将涉及东南极洲和西南极洲之间的运动。对晚白垩世和新生代运动的估计来自于将连接东南极洲到澳大利亚到豪勋爵海隆到太平洋板块再到西南极洲的板块回路相加。然而，该地区板块运动的历史仍然存在重大的不确定性，导致对全球板块回路的影响大相径庭，没有明确的迹象表明哪种模型是正确的。PI建议将这一运动分为两部分：42 Ma以来的运动和42 Ma之前的运动。对于较年轻的时间间隔，PI将通过利用不寻常的板几何形状来提高旋转的准确性，使他们能够解决五边界，四板配置。对于较旧的时间间隔，计算东南极洲和西南极洲之间运动的唯一方法是通过长的Aus-Pac板块回路。 在这个时间间隔的困难是，有三套旋转有明显不同的结果为澳东蚂蚁边界。Aus和Ant在50 Ma前的基本运动上的分歧导致了罗斯海西部和埃尔斯沃思地附近的运动预测存在很大差异。PI建议重新检查Aus-Pac板电路中的关键元素，目的是减少不确定性，在可能的情况下使用定量方法，并解决涉及替代解释的一些关键问题。更广泛的影响：这项工作的科学影响是提高了对南极板块构造历史的理解，以纳入全球模型。该项目将支持每个机构的一名研究生。该项目的结果将在全球板块运动和板块重建数据库中提供。此外，调查结果将用于向中学团体开展外联工作。坎德制作了一部动画电影，讲述了他在本科和研究生教学中使用的澳大利亚太平洋板块电路周围的板块运动。他计划使用这个项目的结果来更新和扩展这个动画。

This proposal will address the motion between East and West Antarctica. The estimates of motion in the Late Cretaceous and Cenozoic come from summing the plate circuit linking East Antarctica to Australia to the Lord Howe Rise to the Pacific plate to West Antarctica. However, major uncertainties remain in the history of the plate motions in this region, leading to widely different implications for the global plate circuit, without a clear indication of which model is correct. The PIs propose to analyze this motion in two parts: motion since 42 Ma and motion before 42 Ma. For the younger time interval, the PIs will improve accuracy of rotations by taking advantage of an unusual plate geometry that enables them to solve a five-boundary, four-plate configuration. For the older time interval, the only way to calculate motion between East and West Antarctica is via the long Aus-Pac plate circuit. The difficulty in this time interval is that there are three sets of rotations with distinctly different results for the Aus-East Ant boundary. The disagreement over the fundamental motion between Aus and Ant before 50 Ma leads to large differences in the predicted motion in the Western Ross Sea and near Ellsworth Land. The PIs propose to re-examine the key elements in the Aus-Pac plate circuit with the objective of reducing uncertainties, using quantitative methods where possible, and resolving some of the critical issues involving alternative interpretations. Broader impacts: The scientific impacts of this work are an improved understanding of Antarctic plate tectonic history to incorporate into global models. This project will support one graduate student at each institution. The results of the project will be made available in the global plate motion and plate reconstruction databases. In addition, results will be used for outreach work to middle school groups. Cande has made an animated movie of the plate motions around the Aus-Pac plate circuit that he uses as part of his undergraduate and graduate teaching. He plans to update and expand this animation using the results of this project.