Collaborative Research:Expedition 322 Objective Research on the nature and history of subsurface flow within the Nankai sediments prior to subduction

合作研究：322探险队 目的 研究俯冲前南开沉积物内地下流的性质和历史

• 批准号: 1029981
• 负责人: Marta Torres
• 金额: $ 18.24万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1029981&HistoricalAwards=false
• 关键词: Collaborative; Research; Expedition; 322; Objective

Intellectual merit: NanTroSEIZE, a central part of the Seismogenic Zone Initiative, is aimed at unraveling hydrologic processes at subduction megathrusts. A key component of the project, and the target of IODP Exp. 322, is the characterization of the incoming sedimentary strata and the top of igneous basement prior to the plate entering the subduction zone. Two reference sites (Sites C0012 and C0011) were drilled in the Shikoku Basin, which, when analyzed in the context of other sites previously drilled seaward of the deformation front (ODP Legs 131 and 190), provide an ideal database to characterize subduction inputs. Though still unaffected by subduction processes, these inputs are influenced by lateral fluid migration from zones of deeperseated dehydration reactions. Constraining this hydrologic regime is key to unraveling the effect of fluids and diagenetic reactions on the geomechanical properties of the plate interface at depth. Shipboard results point to the intriguing possibility of two fluids from different sources migrating through the sedimentary strata seaward of the trench. One regime (characterized by fluid freshening and the presence of methane and higher hydrocarbons) is driven by expulsion of fluids from the subducting sediment and up-dip migration through high permeability horizons in the subduction inputs. The other flow regime (characterized by the presence of sulfate at depth) is driven by migration of a seawater-like fluid through the upper oceanic crust into the sandstone turbidites of the overlying sediment. At the interface of both fluid regimes, microbial activity appears to be stimulated; with a newly discovered deep zone of active anaerobic oxidation of methane (AOM) at approximately 417 mbsf, where peak methane concentrations coincide with the complete consumption of sulfate and a marked increase in pore-water sulfide. Here we propose to: 1) characterize the nature of these flow regimes using pore water data in a collaborative program with other shipboard scientists; and 2) extrapolate these findings through time by analyses of authigenic phases (carbonates and barites), which contain a record of fluidsources (strontium isotopes), metabolic processes (carbon and sulfur isotopes) and formation temperatures (clumped oxygen isotopes). The recently developed clumped oxygen isotope (i.e. multiply-substituted isotopologues) analysis has been shown to effectively constrain temperatures of crystallization to ± 2.4 °C. Measurement on select carbonate veins and cements recovered nearthe bottom of the holes will provide key data on fluid temperatures needed to characterize: the state properties of the incoming sediments; temperature-dependent diagenetic reactions; and subsurface microbial communities. No in situ temperature data was collected during Exp. 322. In addition to providing information on basic geochemistry in the lower strata of the incomingplate (a key objective of Exp. 322), the data sets generated here will be used to further our understanding of newly postulated and highly significant topics: 1) history and nature of flow in the lower strata of the incoming plate, which may include an -as of yet undocumented- fluid flow regime in the upper oceanic crust; and 2) deep biosphere processes, which include a newlydiscovered AOM zone that is sustained by the electron acceptors supplied by an upper basement flow of sulfate bearing fluids.Broader impact: The data set we will assemble will allow us to provide fundamental information on the role of fluids on the geochemical, geomechanical and geobiological processes in the subducting strata, a key objective of the expedition. Our data will be shared with other NantroSeize scientists, in a fully integrated and cooperative effort. In addition to thesecollaborations, Prof. Peckman (U. of Bremen) has agreed to analyze biomarkers in the carbonates at no cost to this proposal. The project will directly support the thesis research of two graduate students, and an undergraduate research fellow. Outreach efforts include dissemination of Seismogenic zone processes through The SMILE program at Oregon State University (http://smile.oregonstate.edu/), Adult Education across the State of Oregon(http://literacyworks.org/ocean/) and professional development courses for in-service teachers through the Math-Science Partnership Program of the Arizona Department of Education.

知识分子的优点：纳特罗斯（Nantroseize）是地震区倡议的中心部分，旨在揭开俯冲巨型层的水文过程。项目的关键组成部分和IODP EXP的目标。 322，是进入俯冲带的板块之前的沉积层和火成岩地下室的表征。在Shikoku盆地中钻了两个参考位点（位点C0012和C0011），当在以前先前先前已钻出变形前线的地点（ODP腿131和190）的地点进行分析时，它提供了一个理想的数据库，以表征俯冲输入。尽管仍然不受俯冲过程的影响，但这些输入受到从较深层面的脱水反应区域的侧向流体迁移的影响。限制这种水文制度是阐明流体和成岩反应对板界面深度的地质力学特性的影响的关键。船上的结果表明，来自不同来源的两种流体的可能性很大，这些流体迁移到沟渠的沉积层面。一种制度（以液体清新为特征，甲烷和较高的碳氢化合物的存在）是由俯冲沉积物中的液体从俯冲沉积物中排出的驱动，并通过俯冲输入中高透密性的高范围驱动。另一个流动状态（以深度为特征的是硫酸盐的存在）是由海水样流体通过海洋上层壳迁移到上衣沉积物的砂岩浑浊的驱动的。在两种流体状态的界面上，微生物活性似乎受到刺激。在大约417 mbsf处的新发现的甲烷（AOM）活性厌氧氧化的深区域，甲烷浓度与硫酸盐的完全消耗和明显的孔隙水硫化物相一致。在这里，我们建议：1）在与其他船上科学家的协作计划中，使用孔隙水数据来表征这些流程度的性质； 2）通过分析身份（碳酸盐和碳酸盐岩）的分析来推断这些发现，其中包含流体库记录（腹地同位素），代谢过程（碳和硫同位素）和形成温度（氧气同位素）。最近开发的簇氧同位素（即多重取代的同位素学）分析已显示出有效地限制结晶温度为±2.4°C。在孔底部附近回收的选择碳酸盐静脉和水泥的测量将提供有关表征所需的流体温度的关键数据：传入沉积物的状态特性；依赖温度的成岩反应；和地下微生物群落。 EXP期间未收集原位温度数据。 322。除了提供传入板的下层阶层中基本地球化的信息（exp。322的关键目的）外，此处生成的数据集还将用于进一步，以进一步了解我们对新发布和高度重要的主题的理解：1）历史和高度重要的板块的历史性质和流动性质的性质和流动板的流动性质，可能包括尚未拆除的流体流动性的较高流量的海洋流动性。 2）深层生物圈过程，其中包括一个新发现的AOM区域，该区域由硫酸盐轴承流体的上层基础流提供的电子受体所维持。BRODER的影响：我们将组装的数据集将使我们能够提供有关流体在地球学，地球力学和地球机械和地理学过程中的基本作用的基本信息。我们的数据将以完全整合和协调的工作与其他纳特罗塞尔科学家共享。除了这些杂物外，不来梅的佩克曼教授同意以无需支付该提案的代价分析碳酸盐中的生物标志物。该项目将直接支持两位研究生的论文研究，并支持一位本科研究员。外展工作包括通过俄勒冈州立大学（http://smile.oregonstate.edu/），俄勒冈州（http：//literacyworks.org/ocean/）的成人教育来传播地震生成区的过程，以及通过数学领域的教育计划，成人教育的成人教育和专业教师的专业发展课程。