Collaborative Research: Improved Cenozoic Plate Reconstructions of the Circum-Antarctic Region

合作研究：改进环南极地区新生代板块重建

• 批准号: 0126334
• 负责人: Joann Stock
• 金额: $ 20.04万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-15 至 2005-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0126334&HistoricalAwards=false
• 关键词: Collaborative; Research; Improved; Cenozoic; Plate

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, provides funds for a project to make use of ship-repositioning transit cruises to gather geophysical information relating to plate tectonics of the Southern Ocean and to support student training activities. Well-constrained Cenozoic plate reconstructions of the circum-Antarctic region are critical for examining a number of problems of global geophysical importance. These problems include, e.g., relating the plate kinematics to its geological consequences in various plate circuits (Pacific-North America, Australia-Pacific); a dynamical understanding of what drives plate tectonics (which requires well-constrained kinematic information in order to distinguish between different geodynamic hypotheses); and an understanding of the rheology of the plates themselves, including the amount of internal deformation they can support, and the conditions leading to the formation of new plate boundaries through breakup of existing plates. By obtaining better constraints on the motion of the Antarctica plate with respect to these other plates, and by better quantifying the internal deformation within Antarctica (between East and West Antarctica), contributions will be made to solving these other fundamental problems.In this project, existing data will be analyzed to address several specific issues related to plate motions involving the Antarctic plate. First, work will be done on four-plate solutions of Australia-Pacific-West Antarctica-East Antarctica motion, in order to most tightly constrain the rotation parameters for separation between East and West Antarctica for the time period from about 45 to 28 Ma (Adare Basin spreading system). This will be done by imposing closure on the four-plate circuit and using relevant marine geophysical data from all four of the boundaries. The uncertainties in the resulting rotation parameters will be determined based on the uncertainties in the data points. These uncertainties can then be propagated in the plate circuit for use in addressing the various global geodynamic problems mentioned above. Second, rotation parameters for Pacific-West Antarctica during Tertiary time will be determined using recently acquired well-navigated Palmer transit data and any additional data that can be acquired during the course of this project. These parameters and their uncertainties will be used in assessments of plate rigidity and included in the plate circuit studies.In the framework of this project, new collection of marine geophysical data will be accomplished on a very flexible schedule. This will be done by collecting underway gravity, magnetics, and swath bathymetric data on Palmer transit cruises of geological importance. This has been successfully done on eight previous Palmer cruises since 1997, the most recent four of which were funded under a collaborative OPP grant to CalTech and Scripps which is now expiring. On one of the suitable transits, a formal class in marine geophysics will be conducted that will afford an opportunity to 12 or more graduate and undergraduate students, from CalTech and Scripps as well as other institutions. In this way, educational activities will be integrated with the usual scientific data collection objectives of the research project.

该奖项由极地项目办公室的南极地质和地球物理项目提供，为利用船舶重新定位过境巡航收集与南大洋板块构造有关的地球物理信息并支持学生培训活动的项目提供资金。环南极地区的新生代板块重建对于研究许多具有全球地球物理重要性的问题至关重要。这些问题包括，例如，将板块运动学与其在各种板块环路（太平洋-北美、澳大利亚-太平洋）中的地质后果联系起来；对板块构造驱动因素的动态理解（这需要良好约束的运动学信息才能区分不同的地球动力学假设）；了解板块本身的流变性，包括它们可以支持的内部变形量，以及通过现有板块的破裂而形成新板块边界的条件。通过更好地约束南极洲板块相对于其他板块的运动，并更好地量化南极洲内部（南极洲东部和西部之间）的内部变形，将为解决这些其他基本问题做出贡献。在该项目中，将分析现有数据，以解决与涉及南极板块的板块运动相关的几个具体问题。首先，将开展澳大利亚-太平洋-西南极洲-东南极洲运动四板块解的工作，以最严格地约束约45至28Ma时期东西南极洲分离的旋转参数（阿黛尔盆地扩张系统）。这将通过对四板电路进行封闭并使用来自所有四个边界的相关海洋地球物理数据来完成。所得旋转参数的不确定性将根据数据点的不确定性来确定。然后，这些不确定性可以在板电路中传播，用于解决上述各种全球地球动力学问题。其次，第三纪期间太平洋-西南极洲的旋转参数将使用最近获得的良好导航的帕尔默凌日数据以及在该项目过程中可以获得的任何其他数据来确定。这些参数及其不确定性将用于评估板块刚度并包含在板块电路研究中。在该项目的框架内，海洋地球物理数据的新收集将以非常灵活的时间表完成。这将通过收集具有地质重要性的帕尔默过境巡航的重力、磁力和条带测深数据来完成。自 1997 年以来，帕尔默邮轮已经在之前的八次航行中成功实现了这一目标，其中最近的四次是由加州理工学院和斯克里普斯的 OPP 合作资助资助的，该资助现已到期。在其中一次合适的凌日中，将开设一门正式的海洋地球物理学课程，为来自加州理工学院、斯克里普斯以及其他机构的 12 名或更多研究生和本科生提供机会。通过这种方式，教育活动将与研究项目的通常科学数据收集目标相结合。