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.

覆盖地球大部分地区的快速扩张的洋壳被认为是分层且均质的。尽管船基研究付出了巨大努力，但仍然缺乏基于自然样本的完整现代化学/岩石学剖面。为了通过快速扩张的海洋地壳建立参考剖面，本研究旨在对阿曼白垩纪蛇绿岩的地壳剖面进行地球化学/岩石学研究，该区域被认为是快速扩张的海洋岩石圈的最佳例子。土地。为此，在 Tayin 河谷地块的 Wadi Gideah 采集了代表约 6.5 公里快速扩张洋壳的完整剖面（辉长岩、岩脉、玄武岩）。在该项目中，我们重点关注 (1) 岩相学和相分析研究，(2) 本体分析表征，(3) 量化硫循环，以及 (4) 使用 Sr 和 O 同位素表征热液蚀变随深度的演化。该剖面在地壳成分的完整性以及所获得的分析数据的质量和一致性方面将是独一无二的。因此，它非常适合增进我们对地壳增生过程以及快速扩张的洋壳中初级和次级地球化学循环演化的理解。最后，阿曼参考剖面为综合海洋钻探计划 (IODP) 在 1256 号地点（赤道太平洋）的钻探提供了科学支持，计划于 2011 年将目前的钻孔深入到辉长岩地壳中。