Fluid flow and diagenesis in the incoming oceanic plate lithostatigraphy to the Sumatra subduction zone: a geochemical approach

进入苏门答腊俯冲带的海洋板块岩石地学中的流体流动和成岩作用：地球化学方法

• 批准号: 320125564
• 负责人: Dr. Andre Hüpers
• 金额: --
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/320125564?language=en
• 关键词: Fluid; flow; diagenesis; incoming; oceanic

On 26 December 2004, the Sumatra-Andaman earthquake with a moment magnitude of Mw=9.2 ruptured approx. 1300 km of the plate interface with coseismic slip propagating seaward to the trench causing the devastating tsunami. The event is unusual because the plate boundary thrust beneath the outermost accretionary prism is usually assumed to be aseismic. A high degree of lithification in the incoming section has been proposed to explain the seaward shift of seismogenic slip and the unusual geometry of the Sumatra accretionary prism. However, validation of this hypothesis is still outstanding because the sedimentary input to the Sumatra subduction zone has not been specifically sampled by scientific ocean drilling so far.The main focus of this research proposal will be the identification and spatio-temporal characterization of important diagenetic, alteration and fluid flow processes in the incoming sediment and oceanic crust to the Sumatra subduction zone. The research will be implemented by geochemical analysis of both pore fluids and sediment/basement samples that will be sampled offshore NW Sumatra during Expedition 362 of the International Ocean Discovery Program in 2016. In detail the work program will encompass: (1) Identification of water-rock interaction processes and their source depths via lithium and boron isotope analysis in combination with fluid and whole rock geochemistry and X-ray diffraction analysis, and (2) integration of the geochemical data with results from flow-through experiments and reaction transport models to understand the hydrogeology of the incoming oceanic plate lithostratigraphy.

2004年12月26日，矩震级为9.2毫瓦的苏门答腊-安达曼地震发生了大约。1300公里的板块界面同震滑动向海沟传播造成了毁灭性的海啸。这一事件是不寻常的，因为在最外层的吸积棱镜下的板块边界推力通常被认为是地震。有人提出，来段的高度岩化作用可以解释发震滑动的向海移动和苏门答腊增生棱镜的不寻常几何形状。然而，这一假设的验证仍然很突出，因为到目前为止，科学海洋钻探还没有对苏门答腊俯冲带的沉积输入进行具体采样。本研究计划的主要重点将是识别和时空特征的重要成岩，蚀变和流体流动的沉积和海洋地壳进入苏门答腊俯冲带。该研究将通过对孔隙流体和沉积物/基底样品的地球化学分析来实施，这些样品将在2016年国际海洋发现计划的第362次探险期间取样于苏门答腊西北近海。具体工作内容包括：(1)结合流体和全岩地球化学及x射线衍射分析，通过锂、硼同位素分析确定水岩相互作用过程及其源深度；(2)将地球化学数据与渗流实验和反应输运模型结果相结合，了解来海板块岩石地层的水文地质。

项目成果

Understanding Himalayan erosion and the significance of the Nicobar Fan

• DOI: 10.1016/j.epsl.2017.07.019
• 发表时间: 2017-10
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: L. McNeill;Brandon Dugan;Jan Backman;K. Pickering;H. Pouderoux;T. Henstock;K. Petronotis;Andrew Carter;F. Chemale;K. Milliken;Steffen Kutterolf;H. Mukoyoshi;Wenhuang Chen;S. Kachovich;F. Mitchison;S. Bourlange;T. Colson;M. Frederik;Gilles Guerin;M. Hamahashi;B. House;A. Hüpers;T. Jeppson;A. R. Kenigsberg;M. Kuranaga;N. Nair;S. Owari;Y. Shan;I. Song;Marta Torres;P. Vannucchi;P. Vrolijk;Tao Yang;Xixi Zhao;Ellen Thomas