High temperature hydrothermal activity in the deep oceanic crust: Experiments and investigations on natural rocks in the Oman ophiolite

深洋地壳的高温热液活动：阿曼蛇绿岩天然岩石的实验和研究

基本信息

批准号：
116858737
负责人：
Professor Dr. Jürgen Koepke
金额：
--
依托单位：
Institut für Mineralogie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2009
资助国家：
德国
起止时间：
2008-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/116858737?language=en
关键词：
temperature hydrothermal activity deep oceanic

项目摘要

The Oman ophiolite is regarded to present the best proxy of fast-spreading oceanic crust on land. Most petrologists/geochemists built on the evidence from Oman ophiolite and favour a general accretion model for fast-spread oceanic crust that deep plutonic crust is formed by multiple intrusions of gabbroic sills. A requirement for this model, however, is a substantial cooling of the deep oceanic crust, and many scientists believe that a seawater-derived high-temperature hydrothermal circulation system must exist. Recent studies based on experimental work revealed that Oman gabbros show characteristic parageneses indicating that partial melting triggered by water-rich fluids proceeded in the deep crust. These can be interpreted as result of hightemperature hydrothermal convection, implying that the distinction between primary magmatic and seawater-induced metamorphic processes is blurred. The present study will combine the investigation of natural rocks of the Oman ophiolite and experimental work on relevant natural systems, and finally theoretical work on thermal modelling, in order to understand one important aspect of fast-spread ocean crust generation: the interplay between magmatic accretion and hydrothermal processes ongoing at high temperatures, and the way how the hydrothermal cooling of the deep crust proceeds.

阿曼蛇绿岩被认为是陆地上快速扩张的洋壳的最佳代表。大多数岩石学家/地球化学家以阿曼蛇绿岩的证据为基础，并赞成快速扩张的洋壳的一般增生模型，即深成岩地壳是由辉长岩基岩的多次侵入形成的。然而，该模型的一个要求是深海地壳的大幅冷却，许多科学家认为必须存在源自海水的高温热液循环系统。最近基于实验工作的研究表明，阿曼辉长岩表现出特征性的共生现象，表明富含水的流体引发的部分熔融在地壳深处进行。这些可以解释为高温热液对流的结果，这意味着原生岩浆和海水引起的变质过程之间的区别是模糊的。本研究将结合对阿曼蛇绿岩天然岩石的调查和相关自然系统的实验工作，最后结合热模拟的理论工作，以了解快速扩张的海洋地壳生成的一个重要方面：岩浆增生之间的相互作用和高温下进行的热液过程，以及地壳深处的热液冷却的进行方式。