Origin, structure and deformation of low-magmatic oceanic lithosphere in the vicinity of ODP Leg 209, Mid-Atlantic Ridge 14N - 16N

大西洋中脊 14N - 16N ODP 209 段附近低岩浆大洋岩石圈的起源、结构和变形

基本信息

批准号：
NE/B500074/1
负责人：
Roger Clive Searle
金额：
$ 18.8万
依托单位：
CARDIFF UNIVERSITY
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FB500074%2F1
关键词：
Origin structure deformation low magmatic

项目摘要

When tectonic plates separate, the peridotite rock in the Earth's upper mantle rises and melts, then the melt cools to form oceanic crust. Generally this crust is 6-7 km thick, but in some areas it is much thinner and may be missing altogether. Such a situation occurs around the Fifteen Twenty Fracture Zone on the Mid-Atlantic Ridge. Here, peridotite crops out extensively for tens of kilometres along the ridge axis, in zones marked by complex topography and faulting. This provides a superb opportunity to study both rocks from the mantle, and the processes by which seafloor spreading takes place in the absence of substantial melt or a thick crust. The ocean drilling programme has already drilled eight deep holes in the area, and we will complement that work with very detailed mapping and taking many more shallow samples. We will image the seafloor using sonar, and use this to map the faults and different rock types. We will then choose sites where we will take up to 60 shallow cores of rock. These samples will be oriented in space, allowing us to determine properties such as the directions of flow, stretching and fracturing as the mantle rocks were emplaced, and subsequent rotations by faulting. Chemical analysis will enable us to unravel details of where these rocks originated and how they melted and subsequently evolved.

当构造板分开时，地球上地幔中的橄榄岩岩石上升并融化，然后融化以形成海洋壳。通常，这种外壳厚6-7公里，但是在某些地区，它更薄，可能完全缺少。这种情况发生在大西洋中部山脊的15个骨折区域附近。在这里，橄榄岩在沿着山脊轴的数十公里处广泛地出现，并以复杂的地形和断层为标志的区域。这为研究地幔研究两种岩石提供了极好的机会，并且在没有大量熔体或厚壳的情况下进行海底扩散的过程。海洋钻井程序已经在该地区钻了八个深孔，我们将以非常详细的映射和采集更多浅样本进行补充。我们将使用声纳对海底进行映像，并使用它来绘制故障和不同的岩石类型。然后，我们将选择最多需要60个浅岩石的地点。这些样品将在空间中定向，使我们能够确定诸如将地幔岩石的流动方向，拉伸和破裂的方向确定，并通过断层进行旋转。化学分析将使我们能够揭示这些岩石起源的位置以及它们如何融化和随后进化的细节。