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

基本信息

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

项目摘要

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.

海底散布在海山山脊上的海洋岩石圈是地球上运行的基本地质过程之一。最重要但最棘手的问题之一是了解山脊下面的岩浆储层如何产生较低的外壳，尤其是在快速扩散速率下。从下层地壳上的gabbroic岩石通常是无法访问的，但在太平洋的赫斯深裂口的侧面构造了构造。 IODP Expedition 345旨在从该地区提供独特的下海洋地壳样品，这将产生对涉及海底扩散涉及的岩浆和构造过程的见解。作为这项工作的一部分，将从回收的核心碎片中收集古磁数据，对于理解该地点下层地壳的演变至关重要。这些数据将提供有关我们期望遇到的磁化磁化强度方向和强度的有价值的信息岩石使海洋磁异常。此外，我们打算将井眼墙内部的古磁数据和地球物理图像组合使用，以重新定位通过钻孔恢复的一些核心部分，从而允许将其他方向性（例如结构数据）恢复到正确的地理参考。框架。