Establishing a reference profile for fast-spreading oceanic crust: Petrology and geochemistry of the "Wadi Gideah" cross section in the Oman ophiolite

为快速扩张的洋壳建立参考剖面：阿曼蛇绿岩“Wadi Gideah”横截面的岩石学和地球化学

基本信息

批准号：
214851514
负责人：
Dr. Carl-Dieter Garbe-Schönberg
金额：
--
依托单位：
Institut für Mineralogie
依托单位国家：
德国
项目类别：
Infrastructure Priority Programmes
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/214851514?language=en
关键词：
Establishing reference profile fast spreading

项目摘要

Fast-spreading oceanic crust covering a large part of our planet is regarded as layered and homogenous. In spite of tremendous efforts by ship-based research, a complete modern chemical/petrological profile based on natural samples is still missing. In order to establish a reference profile through fast-spreading oceanic crust, the present study aims to perform a geochemical/petrological investigation of a crustal section in the Cretaceous ophiolite of Oman, which is regarded as the best example of fast-spreading oceanic lithosphere on land. For this, a complete section (gabbros, dikes, basalts) representative of approximately 6.5 km of fast-spreading oceanic crust was sampled at the Wadi Gideah in the Wadi Tayin massif. Within this project we focus on (1) petrography and phase analytical studies, (2) bulk-analytical characterization, (3) quantifying sulfur cycling and (4) characterizing the evolution of hydrothermal alteration with depth by using Sr and O isotopes. This profile will be unique in terms of completeness of the crustal components and quality and coherence of analytical data to be obtained. Hence, it is well-suited for advancing our understanding of crustal accretion processes and the evolution of primary and secondary geochemical cycles at fast-spreading oceanic crust. Finally, the Oman reference profile provide scientific support for the drilling of the Integrated Ocean Drilling Program (IODP) at Site 1256 (equatorial Pacific) where the deepening of the present hole down into the gabbro crust is scheduled for 2011.

覆盖我们地球的大部分的快速扩张的海洋壳被认为是分层和同质的。尽管基于船舶的研究做出了巨大的努力，但基于天然样品的完整现代化学/岩石学概况仍然缺失。为了通过快速扩张的海洋地壳建立参考曲线，本研究旨在对阿曼白垩纪蛇绿岩的地壳截面进行地球化学/岩石学研究，该层被认为是陆地上快速扩张的海洋岩石圈的最佳例子。为此，在Wadi tayin massif的Wadi Gideah中采样了一个约6.5 km快速扩张的海洋地壳的完整部分（Gabbros，Dikes，玄武岩）。在该项目中，我们关注（1）岩石学和相分析研究，（2）批量分析表征，（3）量化硫循环的量化和（4）（4）通过使用SR和O同位素来表征深度水热改变的演变。从地壳组件的完整性以及要获得的分析数据的质量和连贯性方面，此概况将是独一无二的。因此，它非常适合促进我们对地壳积聚过程的理解以及在快速扩张的海洋壳中的原代和次级地球化学循环的演变。最后，阿曼参考曲线为钻探计划（赤道太平洋）的综合海洋钻井程序（IODP）提供了科学支持，在该计划将在2011年将目前的孔深入Gabbro地壳。