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.

将近50年的板块构造一直是地球科学的基本宗旨，但是仍然存在基本问题，例如板块的基部在哪里，什么使板上的板“类似板”？更好地理解从刚性岩石圈板到下面较弱的地幔的过渡对板块构造，自然危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板基底的深度和性质，但迄今未达成共识。例如，已知温度对岩石的机械行为具有很强的影响，如果这是统治板的定义的唯一过程，那么我们希望在海洋山脊附近看到一个薄板，而在旧海底下方的板非常厚。然而，许多地球物理研究在所有海底年龄都观察到了几乎恒定的厚度板。这导致科学家提出了其他机制，例如地幔脱水以增强地幔形成刚性板。同样，对非常强烈的异常的观察使其他人暗示可能存在熔体以削弱板下面的地幔。但是，这些观察中的许多仅来自一个海洋，太平洋，来自间接的，远程观察，在不同的区域和尺度上，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，阻碍了对构造板的完全理解。我们将系统地对海洋板的整个长度进行成像，从大西洋山脊的出生到其在非洲边缘最古老的地层。这是一项大规模的集中精力，使用地震和电磁方法从米到公里的多个分辨率和灵敏度。这种规模，焦点和跨学科方法最终将确定使板强大并定义它的过程和属性。该项目将通过涉及欧盟合作伙伴（3.5 m欧元）和行业（640万欧元）的大型，集中的国际合作来完成，两者都已经获得资金。