Collaborative Research: Expedition 322 Objective Research on Sediment-Pore Water Interactions Controlling Sediment Cementation and Deformation in the NanTroSEIZE Drilling Transect

合作研究：Expedition 322 沉积物与孔隙水相互作用的客观研究控制 NanTroSEIZE 钻探断面的沉积物胶结和变形

• 批准号: 1059924
• 负责人: Marta Torres
• 金额: $ 13.65万
• 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: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1059924&HistoricalAwards=false
• 关键词: Collaborative; Research; Expedition; 322; Objective

Cementation affects the mechanical properties that control sediment strength and deformation. A small volume of grain coating cement can greatly increase sediment strength. Therefore, even minor cementation may affect consolidation in basins and control deformation in accretionary margins. The effects of grain-coating silica cement on the physical properties of sediment on the Philippine Sea plate as it approaches the Nankai Trough subduction zone in the central and southwestern portions of the Shikoku Basin were documented by previous work on samples from Deep Sea Drilling Project Site 297 and Ocean Drilling Program Sites 1173 and 1177. At these sites, a small amount of glass disseminated throughout hemipelagic sediment is altered to a silica gel upon burial. The gel coats grain contacts, and inhibits sediment consolidation. The cemented sediment has anomalous porosity, seismic velocity, and rigidity. With further burial, onset of tectonic deformation, and increasing temperature, cement dissolution and mechanical breakdown leads to dramatic reduction in rigidity and collapse of the sediment framework (i.e. porosity loss). How do differences in sediment thermal history, fluid flow, and pore water chemistry between sites control shifts in the location and extent of the cemented zone? How does the incorporation of cemented units with transient properties into the margin wedge influence the nature and distribution of deformation? Toward answers to these questions, the silica cement distribution at IODP Sites C0011 and C0012 will be determined, and multicomponent reactive transport modeling for Sites C0011, C0012, 1173, and 1177 will be performed. The shear-wave velocity of samples from NanTroSEIZE drilling sites C0011 and C0012 will be determined to locate regions of anomalous strengthening. The four sites selected for examining sediment-pore water interactions provide a range of sediment accumulation and thermal histories. The results will allow examination of the effects of fluid flow rate and thermal state on the vertical location and extent of silica cementation in the Shikoku Basin sediments. The proposed investigation addresses one of the main goals of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE); to determine how geologic differences affect mechanical properties, permeability, fluid flow, pore pressure, shear strength, and earthquake rupture processes within the Nankai margin. The proposed study may transform our understanding of accretionary margin processes by shedding light on a previously underappreciated control on wedge deformation. By examining processes that control cementation of sediment entering a subduction zone, the proposed research has societal relevance as it advances understanding of the mechanisms at play in potentially hazardous seismogenic margins. Deformation features control fluid drainage through a margin wedge. Therefore, sediment cementation and deformation impact margin hydrogeology and fluid pressure, which are related to strain accumulation and seismicity on the plate interface. The proposed research will be of interest to seismologists, geochemists, and hydrogeologists. This work enhances human resources by funding a graduate student at New Mexico Tech (NMT), a Hispanic-Serving Institution. The proposed project will enhance facilities used for both research and teaching at NMT. Outreach efforts include dissemination of seismogenic zone processes through The SMILE program at Oregon State University (http://smile.oregonstate.edu/), and through an ongoing Adult Education program at COAS (http://literacyworks.org/ocean/). In addition, the Pi?fs will work with the COSEE?]Pacific Partnerships (www.coseepacificpartnerships.org) by participating in one of their ?gscience pub nights?h in Newport, OR discussing earthquake related processes around the Pacific Rim.

胶结影响控制沉积物强度和变形的机械性能。少量的谷物涂层水泥可以大大增加沉积物强度。因此，即使是较小的胶结也可能影响盆地的巩固和积聚边缘的控制变形。 The effects of grain-coating silica cement on the physical properties of sediment on the Philippine Sea plate as it approaches the Nankai Trough subduction zone in the central and southwestern portions of the Shikoku Basin were documented by previous work on samples from Deep Sea Drilling Project Site 297 and Ocean Drilling Program Sites 1173 and 1177. At these sites, a small amount of glass disseminated throughout hemipelagic sediment is altered to a埋葬时硅胶。凝胶涂层谷物接触，并抑制沉积物合并。胶结的沉积物具有异常的孔隙度，地震速度和刚度。随着进一步的埋葬，构造变形的发作以及温度升高，水泥溶解和机械崩溃会导致刚性急剧降低和沉积物框架塌陷（即孔隙率损失）。在胶结区的位置和范围内，沉积物热历史，流体流量和孔隙水化学的差异如何？将具有瞬态特性的水泥单元掺入边缘楔形楔中如何影响变形的性质和分布？要回答这些问题，将确定IODP位点和C0012的二氧化硅水泥分布，并将对位点C0011，C0012、1173和1177进行多组分的反应性传输模型。将确定来自Nantroseize钻孔位点C0011和C0012的样品的剪切波速度，以定位异常增强的区域。选择用于检查沉积物孔隙水相互作用的四个地点提供了一系列的沉积物积累和热历史。结果将允许研究流体流量和热态对shikoku盆地沉积物中硅胶胶结的影响。拟议的调查介绍了南卡槽地震区实验（Nantroseize）的主要目标之一。为了确定地质差异如何影响机械性能，渗透率，流体流动，孔隙压力，剪切强度和地震破裂过程。拟议的研究可能会通过阐明以前对楔形变形的控制不足的控制来改变我们对增生边缘过程的理解。通过检查控制进入俯冲带的沉积物胶结的过程，拟议的研究具有社会意义，因为它可以提高对潜在危险的地震生成缘的理解。变形特征通过边缘楔形控制流体排水。因此，沉积物胶结和变形会影响边缘水文地质和流体压力，这与板界面上的应变积累和地震性有关。拟议的研究将吸引地震学家，地球化学家和水文地质学家。这项工作通过资助西班牙裔服务机构的新墨西哥理工学院（NMT）的研究生来增强人力资源。拟议的项目将增强NMT研究和教学的设施。推广工作包括通过俄勒冈州立大学（http://smile.oregonstate.edu/）的微笑计划以及通过COAS（http://literacyworksworkworkss.org/ocean/）进行的成人教育计划来传播地震生成区的过程。此外，PI？fs将与Cosee？] Pacific合作伙伴关系（www.coseepacificpartnerships.orgss.org），通过参加他们在纽波特的一个Gscience Pub Nights？h或讨论太平洋RIM周围的地震相关过程。