Toward an understanding of Neogene plate dynamics: Completion of a high-resolution, closure-enforced chronology of global plate motions since 20 Ma

了解新近纪板块动力学：完成 20 Ma 以来全球板块运动的高分辨率、封闭强制年表

• 批准号: 1433323
• 负责人: Dennis DeMets
• 金额: $ 30.23万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1433323&HistoricalAwards=false
• 关键词: Toward; understanding; Neogene; plate; dynamics

Motivated by work to date, which documents changes in the motions of all the major tectonic plates during the Neogene period (~23-2.5 million years ago), the proposed effort will systematically quantify the geographic scope, nature, and timing of global plate motion changes since 20 million years ago. The Principle Investigators will create a first-ever kinematic framework that will be broadly useful for understanding the relationship of instantaneous plate movements measured by geodetic techniques to movements over millions of years, as well as for modeling the forces that have determined plate motions during the Neogene. The results will be broadly useful to geoscientists, particularly geodesists, paleomagnetists, seismologists, structural geologists, and plate dynamicists. Key papers published on this topic over the past few decades have been cited thousands of times and provide an essential conceptual and quantitative framework for teaching and understanding the Neogene tectonic and geologic evolution of the ocean basins and nearly all the continents. The Principle Investigators will complete a high-resolution chronology of global plate motions since 20 million years ago, comprising most of the Neogene period. Sequences of closure-enforced plate rotations, at ~1 million year intervals, will describe the relative motions since 20 million years ago of all the major plates. The path to completing the study is well defined and consists of (1) new identifications of magnetic reversals from the southern Mid-Atlantic Ridge and Southeast Indian Ridge, as well as compilation of suitable fracture zone and transform fault flow lines along these and other spreading centers, (2) updates to largely complete sets of magnetic anomaly identifications from the southern Central Indian Ridge and Gulf of Aden, (3) compilations of existing reversal identifications from Pacific Basin spreading centers, if suitable, or new identifications for some Pacific Basin spreading centers, (4) methodological upgrades to estimate rotations consistent with plate circuit closures, to search more efficiently for best solutions, to include random and systematic data errors and the influence of the data geometry in rotation uncertainties, and to use a Bayesian methodology to suppress random noise in the rotation sequences. Half or more of the work needed to build the Neogene model has already been accomplished, partly by the Principle Investigator and a Russian collaborator via two NSF-funded projects that have spanned the past decade and partly by other investigators who have worked on the Neogene plate tectonics of the Pacific Basin. The existing data already include nearly 40,000 magnetic reversal identifications interpreted by the Principle Investigator for existing projects and 15,000 crossings of oceanic fracture zones and transform faults. Abundant data are available for completing the proposed analysis, including high-quality aeromagnetic data from the southern Mid-Atlantic Ridge that were previously unavailable for this kind of work.

受迄今为止的工作的启发，记录了所有主要构造板块在新第三纪时期（约2300 - 250万年前）的运动变化，拟议的工作将系统地量化自2000万年前以来全球板块运动变化的地理范围，性质和时间。主要研究人员将创建一个有史以来第一个运动学框架，该框架将广泛用于理解通过大地测量技术测量的瞬时板块运动与数百万年来的运动之间的关系，以及对决定新近纪板块运动的力量进行建模。研究结果对地球科学家，特别是大地测量学家、古地磁学家、地震学家、构造地质学家和板块动力学家有广泛的参考价值。在过去几十年中发表的关于这一主题的重要论文已被引用数千次，并为教学和理解海洋盆地和几乎所有大陆的新近纪构造和地质演化提供了一个重要的概念和定量框架。主要研究人员将完成自2000万年前以来全球板块运动的高分辨率年表，包括新近纪的大部分时间。封闭强制板块旋转的序列，以约100万年的间隔，将描述自2000万年前以来所有主要板块的相对运动。完成这项研究的途径是明确的，包括：（1）对南大西洋中脊和东南印度洋中脊的磁反转进行新的鉴定，以及沿沿着这些和其他扩张中心汇编适当的断裂带和转换断层流线，（2）对南印度洋中脊和亚丁湾的磁异常鉴定进行基本完整的更新，（3）汇编太平洋海盆扩张中心现有的反转鉴定资料（如果合适的话），或对某些太平洋海盆扩张中心进行新的鉴定，（4）更新方法，以估计与板块回路闭合一致的旋转，更有效地搜索最佳解决方案，包括随机和系统数据误差以及旋转不确定性中数据几何形状的影响，并使用贝叶斯方法来抑制旋转序列中的随机噪声。建立新第三纪模型所需的一半或更多的工作已经完成，部分是由主要研究者和俄罗斯合作者通过两个NSF资助的项目完成的，这些项目跨越了过去十年，部分是由其他研究太平洋盆地新第三纪板块构造的研究人员完成的。现有的数据已经包括由首席研究员为现有项目解释的近40，000个磁反转识别以及15，000个海洋断裂带和转换断层的交叉。有丰富的数据可用于完成拟议的分析，包括来自南大西洋中脊的高质量航空磁力数据，这些数据以前无法用于此类工作。