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Structure and evolution of Axial Volcanic Ridges: Constraining the architecture, chronology and evolution of ocean ridge magmatism.

轴状火山脊的结构和演化：限制洋脊岩浆作用的结构、年代和演化。

基本信息

批准号：
NE/C520598/1
负责人：
Roger Clive Searle
金额：
$ 26.78万
依托单位：
Durham University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FC520598%2F1
关键词：
Structure evolution Axial Volcanic Ridges

项目摘要

Mid-ocean ridges (MORs) are the loci of the most voluminous volcanism on our planet, the products of which have generated 60% of the Earth's surface crust. Unlike its sub-aerial counterpart, MOR volcanism is hidden from view beneath several kilometres of water, leaving the processes largely unknown. For many MORs, this volcanism forms axial volcanic ridges (AVRs), a few kilometres wide and tens of kilometres long, which appear episodic or cyclic in their evolution. Although the processes that generate AVRs, their episodicity, effusion rates and links to melt extraction from the Earth's mantle are the focus of much speculation, little is actually known in sufficient detail to unravel their evolution. This is largely because we have not had the tools capable of studying volcanic architecture, sampling volcanic stratigraphy or determining age relationships between erupted units at the fine scale required. In recent years a new generation of submersible instruments has been developed that now allow us to image to sub-metre resolutions and to collect samples to similar precision, and hence to address AVR genesis directly. Recent developments in dating techniques, coupled with improvements in the precision of geochemical analyses, are now providing the means to test many of the models describing MOR volcanism. Here, we propose a detailed study using the high-resolution tools now available to unravel the complex processes of MOR volcanism. We will use measurements of the variation of the Earth's magnetic field strength, variations in sediment accumulation, and radiomentric dating (including newly-developed uranium series dating) of young basalts, to estimate precise ages. The complexity of the study requires collaboration across different laboratories and between different continents. By pooling our resources in this international programme. our study will yield new insights into the time scales, eruption rates, lava volumes and interaction between the volcanoes and their underlying mantle source. These insights are essential if we are to understand this key component of the Earth System - and hence its relationship to Earth evolution as a whole.

大洋中脊是地球上最大的火山活动的所在地，其产物产生了地球表面60%的地壳。不像它在空中的对应物，莫尔火山活动隐藏在几公里深的水下，使其过程在很大程度上不为人知。对于许多MOR，这种火山作用形成了几公里宽、几十公里长的轴向火山脊，在其演化过程中似乎是间歇性或周期性的。虽然产生AVR的过程，它们的发作性，渗出率和与地幔熔体提取的联系是许多猜测的焦点，但实际上很少有足够的细节来揭示它们的演变。这在很大程度上是因为我们还没有能够研究火山结构、对火山地层进行取样或以所需的精细尺度确定喷发单元之间的年龄关系的工具。近年来，新一代的潜水仪器已经开发出来，现在使我们能够以亚米分辨率成像，并以类似的精度收集样本，从而直接解决AVR的成因。测年技术的最新发展，加上地球化学分析精度的提高，现在提供了测试描述莫尔火山作用的许多模型的手段。在这里，我们提出了一个详细的研究，使用高分辨率的工具，现在可以解开复杂的过程莫尔火山作用。我们将使用测量地球磁场强度的变化，沉积物积累的变化和年轻玄武岩的放射性定年（包括新开发的铀系定年），以估计精确的年龄。这项研究的复杂性需要不同实验室和不同大陆之间的合作。把我们的资源集中在这个国际项目上。我们的研究将对火山的时间尺度，喷发速率，熔岩体积以及火山与其下地幔源之间的相互作用产生新的见解。如果我们要理解地球系统的这一关键组成部分，以及它与整个地球演化的关系，这些见解是必不可少的。