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，板块构造学一直是地球科学的基本原理，但基本问题仍然存在，例如板块的底部在哪里以及是什么使板块成为“板块状”？更好地了解从刚性岩石圈板块到下方较弱地幔的转变对于板块构造、自然灾害和气候变化的驱动力具有重要意义。有许多代理用于估计构造基底的深度和性质板，但迄今为止尚未达成共识。例如，众所周知，温度对岩石的力学行为有很大影响，如果这是控制板块定义的唯一过程，那么我们预计会在大洋中脊附近看到一个薄板块和一个非常厚的板块。旧海底下的板块。然而，大量地球物理研究观察到，在所有海底年龄，板块厚度几乎恒定。这导致科学家们提出了其他机制，例如使地幔脱水以强化地幔以形成刚性板块。同样，对非常强烈的异常现象的观察使其他人提出，可能存在熔化现象，从而削弱了板块下方的地幔。然而，这些观测结果中有许多仅来自太平洋这一大洋，是在不同区域和尺度上进行的间接、远程观测，对地球特性具有不同的敏感性。尽管结果令人鼓舞，但研究之间的比较具有挑战性，阻碍了对构造板块的全面了解。我们将系统地对海洋板块的整个长度进行成像，从它在大西洋中脊的诞生到非洲边缘最古老的形成。这是一项大规模的集中工作，具有多个尺度的分辨率和灵敏度，从米到千米尺度，使用地震和电磁方法。这种规模、重点和跨学科方法将最终决定使板材坚固并定义它的工艺和特性。该项目将通过大规模、集中的国际合作来完成，其中涉及欧盟合作伙伴（350 万欧元）和工业界（640 万欧元），双方均已获得资助。