Documenting Dynamic Accretion in the Lower Ocean Crust: Ocean Drilling Holes U1473A and 735B, SW Indian Ridge

记录下洋地壳的动态吸积：印度洋海岭西南部的大洋钻探 U1473A 和 735B

• 批准号: 1637130
• 负责人: Henry Dick
• 金额: $ 49.5万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1637130&HistoricalAwards=false
• 关键词: Documenting; Dynamic; Accretion; Lower; Ocean; Documenting; Dynamic; Accretion; Lower; Ocean

The size, shape, mineralogy, and physical behavior and evolution of magma chambers beneath ocean ridges determine the geochemical, geophysical, hydrothermal, and tectonic characteristics of ocean crust, which forms over 70 percent of Earth's surface (i.e., all that occurring under the sea). To learn more about slow-spread ocean crustal structure, a major community-driven effort to drill deep bore holes into magmatic rocks on the seafloor by the International Ocean Discovery Program and involving more than 30 scientists from around the world, was carried out in 2015-2016 on the Southwest Indian Ridge at a location called the Atlantis Bank. The research that will be carried out under the auspices of this award is divided into two parts. One part consists of creating the foundational geochemical analytical data for over 300 igneous rock specimens of the 789 meter-long core, with the second part involving targeted studies of discrete core intervals to look at the origin of local features. Results of this stratigraphic work will be compared to similar data collected from an ocean drilling core taken 2.2 kilometers away a number of years ago. Broader impacts of the work include strong international collaboration with French, German, Italian, and Chinese scientists, support of a multi-national science program to understand the composition and magmatic section of the seafloor, and the training of two graduate students, one US and one Chinese, with the second being paid for by the Chinese government. Efforts will be made to transmit findings to the public via podcasts and the participation of a professional science communicator.The laboratory part of the research consists of carrying out and creating a geochemical database of whole rock and mineral major and trace element data. Each sample will be examined petrographically to determine mineral and textural relationships and discriminate between primary, secondary, and alteration phases and features. In addition, rare earth element compositions in coexisting plagioclase and pyroxene will be used as geothermometers to develop chemical zoning profiles and thermal histories of the various magmatic bodies within the stratigraphic section. These data will form the basis for the testing of the hypothesis that there is a continuity of igneous process across the Atlantis Bank, reflecting steady-state conditions of emplacement of a core complex. Results of this work can be extrapolated to help us understand other slow-spread crustal areas along the mid-ocean ridges.

海脊下岩浆室的大小，形状，矿物学和身体行为以及岩浆室的演变决定了海壳的地球化学，地球物理，水热和构造特征，该特征形成了地球表面70％以上（即所有发生在海底下）。 为了了解有关慢速海洋甲壳结构的更多信息，由国际海洋发现计划的大型社区驱动的努力，通过国际海洋发现计划钻入海底的岩浆岩石，并在2015年至2016年在西南印度山脊上进行了一家称为Atlantis Bank的地点的西南印度山脊。 将在该奖项的主持下进行的研究分为两个部分。一个部分包括为789米长的核心的300多个火成岩标本创建基础地球化学分析数据，第二部分涉及对离散核心间隔的有针对性研究，以查看本地特征的起源。 这项地层工作的结果将与几年前从2.2公里远的海洋钻井核心收集的类似数据进行比较。 这项工作的更广泛的影响包括与法国，德语，意大利语和中国科学家的强大国际合作，支持了一项跨国科学计划，以了解海底的构图和岩浆部分，以及对两名研究生的培训，一名我们和一名中国人，第二个是由中国政府支付的。将努力通过播客和专业科学沟通者的参与向公众传播发现。研究的一部分包括进行和创建整个岩石和矿物专业和微量元素数据的地球化学数据库。 每个样品将在岩石学上进行检查，以确定矿物质和纹理关系，并区分主要，次要和变化阶段和特征。此外，在斜长石和辉石中共存的稀土元素组成将用作地理热计，以开发地层区域内各种岩浆物体的化学分区分析曲线和热历史。这些数据将构成测试假设的基础，即亚特兰蒂斯银行在亚特兰蒂斯河岸存在火成点的连续性，这反映了核心复合物的稳态条件。 可以推断这项工作的结果，以帮助我们了解中山脊沿岸的其他慢阳性地壳区域。