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Passive Imaging of the Lithosphere Asthensphere Boundary (PiLAB)

岩石圈软流圈边界被动成像 (PiLAB)

基本信息

批准号：
NE/M003507/1
负责人：
Catherine Rychert
金额：
$ 99.66万
依托单位：
University of Southampton
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FM003507%2F1
关键词：
Passive Imaging Lithosphere Asthensphere Boundary

项目摘要

Plate tectonics has been a fundamental tenet of Earth Science for nearly 50 years, but fundamental questions remain, such as where is the base of the plate and what makes a plate, "plate-like?" A better understanding of the transition from the rigid lithospheric plate to the weaker mantle beneath has important implications for the driving forces of plate tectonics, natural hazards, and climate change.There are many proxies used to estimate the depth and nature of the base of tectonic plates, but to date no consensus has been reached. For example, temperature is known to have a strong effect on the mechanical behaviour of rocks, and if this were the sole process governing the definition of the plate, then we would expect to see a thin plate near a mid ocean ridge and a very thick plate beneath old seafloor. However numerous geophysical studies observe what are interpreted as nearly constant thickness plate at all seafloor ages. This has led scientists to propose other mechanisms, such as dehydration of the mantle to strengthen the mantle to form a rigid plate. Similarly, observations of very strong anomalies have led others to suggest that melt might exist to weaken the mantle beneath the plates. However many of these observations come from only one ocean, the Pacific, from indirect, remote observations, at different areas and scales, and with different sensitivities to earth properties. Although results have been promising, comparisons among studies are challenging, hindering a complete understanding of the tectonic plate.We will systematically image the entire length of an oceanic plate, from its birth at the Mid Atlantic Ridge to its oldest formation on the African margin. This is a large-scale focused effort with multiple scales of resolution and sensitivity, from a metre to kilometre scale using seismic and electromagnetic methods. This scale, focus, and interdisciplinary approach will finally determine the processes and properties that make a plate strong and define it. The project will be accomplished through a large, focused international collaboration that involves EU partners (3.5 M euro) and industry (6.4M euro), both already funded.

近50年来，板块构造一直是地球科学的一个基本原则，但基本问题仍然存在，例如板块的底部在哪里，是什么使板块成为“板块状”？“更好地理解从坚硬的岩石圈板块到下面较弱的地幔的过渡对板块构造、自然灾害和气候变化的驱动力具有重要意义。有许多替代物用于估计构造板块底部的深度和性质，但迄今为止还没有达成共识。例如，已知温度对岩石的力学行为有很大的影响，如果这是决定板块定义的唯一过程，那么我们预计在大洋中脊附近会看到一个薄板块，而在旧海底下会看到一个非常厚的板块。然而，许多地球物理学研究观察到的是在所有海底年龄被解释为厚度几乎恒定的板块。这使得科学家们提出了其他机制，例如地幔脱水以加强地幔形成刚性板块。类似地，对异常现象的观测也让其他人认为熔融的存在可能会削弱板块下方的地幔。然而，这些观测中有许多只来自太平洋这一个大洋，来自间接的远程观测，在不同的地区和尺度上，对地球特性的敏感性也不同。虽然结果是有希望的，但研究之间的比较是具有挑战性的，阻碍了对构造板块的完整理解。我们将系统地成像大洋板块的整个长度，从它在大西洋中脊的诞生到它在非洲边缘的最古老的形成。这是一项大规模的有重点的工作，具有多种分辨率和灵敏度，从一米到公里，使用地震和电磁方法。这种规模、重点和跨学科的方法将最终决定使板块强大的过程和属性，并定义它。该项目将通过一个大型的、有重点的国际合作来完成，涉及欧盟合作伙伴（350万欧元）和行业（640万欧元），两者都已获得资助。