Understanding axial melt lens dynamics and lower crust accretion at fast-spreading mid-ocean ridges: new insights from drill cores obtained by the ICDP Oman Drilling Project

了解快速扩张的洋中脊的轴向熔融透镜体动力学和下地壳增生：ICDP阿曼钻探项目获得的钻芯新见解

• 批准号: 398945252
• 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: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/398945252?language=en
• 关键词: Understanding; axial; melt; lens; dynamics

In winter 2016/17, the ICDP drilling initiative "Oman Drilling Project" (OmanDP) successfully penetrated the lower paleocrust of the Oman ophiolite, the world’s largest, best-exposed, and most-studied section of subaerially exposed oceanic lithosphere. The cores are 400 m long and were recovered with a nearly 100 % success rate, making them a uniquely valuable resource for petrographical, petrological, geochemical and structural study and ensuring access to coherent sections throughout critical zones of a fast-spreading oceanic crust: the lowermost layered gabbros (core GT1), the layered to foliated gabbro transition (core GT2), and the gabbro/dike transition (core GT3). The drilled transects through the plutonic crust of the Oman paleocrust can be regarded as a Rosetta Stone for understanding the mode of accretion and cooling of fast-spread oceanic crust that covers about one third of our planet. The proposed project focuses on four main scientific targets: (1) exploring of axial melt lens dynamics at the gabbro/dike transition, (2) investigating the nature of the transition between layered and foliated gabbro in the mid-crust (3) understanding the mechanisms of layer-forming processes in the deep, layered crust, and (4) testing the hypothesis that amphibole-bearing patches/veins formed in the magmatic-metamorphic regime are the results of initial cooling of the deep crust. We plan to integrate petrographical, petrological, geochemical and micro-structural work (lattice preferred orientation using electron backscattering diffraction) on layered, foliated and varitextured gabbros. The results will establish the basis for a deep understanding of the magmatic and initial hydrothermal processes within the axial melt lens and surrounding crystal mush, which form the magma chambers at the end of the melting column beneath mid-ocean ridges.

在2016/17年冬季，ICDP钻探计划“（OMANDP）成功地渗透了Ophiolite Orld Orld最大，最受欢迎且最受欢迎的海洋裸露的海洋质地岩石的下浅乳状，核心是400 m，几乎被回收了100％的成功率，使岩石学和结构研究的宝贵资源确保在整个关键区域（核心GT1）中使用相干部分，laDild trandect通过plutonic sT。了解我们的行星的快速海洋壳的模式和冷却。在深t中的crust（3）中，（4）测试了在岩浆中形成的含闪石的斑块/静脉的假设是深层地壳的初始冷却。使用电子后散射衍射）在层状和varitex的gabbbros上，将建立对岩浆和初始的麦芽式麦芽汁的基础。