Palaeomagnetic constraints on lower oceanic crustal processes (IODP Expedition 345 Hess Deep Plutonic Crust

古地磁对下层大洋地壳过程的限制（IODP Expedition 345 Hess Deep Plutonic Crust

• 批准号: NE/K011057/1
• 负责人: Antony Morris
• 金额: $ 3.24万
• 依托单位: Plymouth University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK011057%2F1
• 关键词: Palaeomagnetic; constraints; lower; oceanic; crustal

Generation of ocean lithosphere by seafloor spreading at mid-ocean ridges is one of the fundamental geological processes operating on Earth. One of the most important yet most intractable problems is to understand how the magma reservoir beneath ridges generates the lower crust, especially at fast spreading rates. Gabbroic rocks from the lower crust are normally inaccessible, but are exposed tectonically on the flanks of the Hess Deep rift in the Pacific Ocean. IODP Expedition 345 aims to provide a unique suite of lower oceanic crustal samples from this locality that will yield insights into magmatic and tectonic processes involved in seafloor spreading. As part of this endeavour, palaeomagnetic data will be collected from recovered core pieces and will be critical to understanding the evolution of the lower crust at this site. These data will provide valuable information on the direction and strength of magnetization locked into the gabbroic rocks we expect to encounter, providing a marker that can be used to infer the amount of tectonic rotation that has affected the site and insights into the contribution that lower crustal rocks make to marine magnetic anomalies. In addition, we intend to use a combination of palaeomagnetic data and geophysical images of the inside of borehole walls to reorient some of the core pieces recovered by drilling, thereby allowing other directional properties (e.g. structural data) to be restored to the correct geographical reference frame.

洋中脊海底扩张形成海洋岩石圈是地球上的基本地质过程之一。最重要但最棘手的问题之一是了解洋脊下的岩浆库如何生成下地壳，特别是在快速扩张的情况下。来自下地壳的辉长岩通常是无法接近的，但在太平洋的赫斯裂谷的侧翼上暴露了构造。IODP远征345旨在提供一套独特的下大洋地壳样品，从这个地方，将产生深入了解海底扩张所涉及的岩浆和构造过程。作为这项工作的一部分，将从回收的岩芯碎片中收集古地磁数据，这些数据对了解该地点下地壳的演变至关重要。这些数据将提供有关我们预计会遇到的辉长岩的磁化方向和强度的宝贵信息，提供一个标记，可用于推断影响该地点的构造旋转量，并深入了解下地壳岩石对海洋磁异常的贡献。此外，我们打算结合使用古地磁数据和钻孔壁内部的地球物理图像来重新定向通过钻探回收的一些岩心块，从而允许将其他方向属性（例如结构数据）恢复到正确的地理参考框架。

项目成果

Earth and Life Processes Discovered from Subseafloor Environments - A Decade of Science Achieved by the Integrated Ocean Drilling Program (IODP)

从海底环境中发现的地球和生命过程 - 综合海洋钻探计划 (IODP) 十年的科学成就

• DOI: 10.1016/b978-0-444-62617-2.00017-7
• 发表时间: 2014
• 作者: Ildefonse B