The origin of Pangea

盘古大陆的起源

• 批准号: 623-2009
• 负责人: Murphy, Brendan
• 金额: $ 7.2万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=520289
• 关键词: origin; Pangea

Over the last 20 years, evidence has been amassing that Pangea, a supercontinent that formed 300 million years ago, is just the latest in a series of supercontinents that have formed repeatedly since the early Precambrian, only to break up and reform again. Although the mechanisms responsible are controversial, many geoscientists agree that repeated cycles of supercontinent amalgamation and dispersal have had a profound effect on the evolution of the Earth's crust, atmosphere, climate, and life. The existence of Pangea, which broke up about 200 million years ago, is a cornerstone of plate tectonics, and its assembly and fragmentation have governed the evolution of the Earth's crust for the past 500 million years. To a first order, we know where and when Pangea formed, but not why. Over the next grant cycle, I intend to investigate why Pangea formed. My approach is to combine field work with laboratory analyses of samples selected from sites that expose critical relationships between rock units. Graduate students are directly involved in each stage of the research program. I will continue to work on the evolution of the Rheic Ocean, an ocean that formed about 500 million years ago between dispersing continents (an interior ocean), and whose closure 200 million years later resulted in the amalgamation of Pangea. However, to obtain a global view, I also need to study rocks that document the evolution of the Paleopacific ocean, an "exterior" ocean that surrounded the dispersing continents. If the evolution of these oceans is dynamically linked, then contraction of the interior ocean, which began about 440 million years ago should be coeval with expansion of the exterior ocean. The dual approach of field work augmented by laboratory analysis will allow me to test the potential geodynamic connection between interior and exterior oceans and to test various hypotheses (including some of my own) that have been proposed for the amalgamation of Pangea.

在过去的20年中，有证据表明，在3亿年前形成的超大陆Pangea只是一系列超级中国的最新一系列，这些超前是自前寒武纪早期以来反复形成的，只是为了再次分手和改革。 尽管负责的机制引起了争议，但许多地球科学家都同意，超大陆融合和分散的重复循环对地球，地壳，大气，气候和生命的演变产生了深远的影响。大约2亿年前破裂的Pangea的存在是板块构造的基石，其组装和分裂统治了过去5亿年的地壳的演变。在第一阶，我们知道pangea在何时何地形成，但不是为什么。在下一个赠款周期中，我打算调查为什么Pangea形成。 我的方法是将现场工作与从暴露岩石单位之间关键关系的地点选择的样本进行实验室分析相结合。研究生直接参与研究计划的每个阶段。我将继续研究Rheic Ocean的演变，Rheic Ocean是一个大约5亿年前分散大洲（一个室内海洋）的海洋，其关闭了2亿年后导致Pangea合并。 但是，为了获得全球观点，我还需要研究记录古族海洋演化的岩石，这是围绕分散大陆的“外部”海洋。如果这些海洋的演变是动态的，那么大约4.4亿年前开始的内部海洋的收缩应随着外部海洋的扩展而同步。实验室分析增强的现场工作的双重方法将使我能够测试内部和外部海洋之间潜在的地球动力学联系，并测试已提出的各种假设（包括我自己的一些假设（包括我自己的）），以使Pangea合并。