论文标题
从阳离子交换能力和IODP Expedition进入北部苏门答腊俯冲带的沉积物中的结合水分含量，间质孔隙度和断裂孔隙率362电阻率数据
Quantification of bound water content, interstitial porosity and fracture porosity in the sediments entering the North Sumatra subduction zone from Cation Exchange Capacity and IODP Expedition 362 resistivity data
论文作者
论文摘要
在这项研究中，我们通过基于IODP Expedition 362数据和裁判后化学分析来量化间质孔隙度，结合的水含量和断裂孔隙度，调查了北苏门答腊俯冲带的沉积输入部分的孔隙率演变。在IODP探险362期间，测量了进入北苏门答腊俯冲带的沉积区的总孔隙率。该总孔隙率源自核心样品的总水含量，包括孔隙水和与果石等含水矿物结合的水。粘土矿物质成分在沉积物区域变化，主要是尼科巴风扇单元中的高岭石/伊利石，在下面的Perfan pelagic单元中是绿地/伊利石。 pelagic单元显示出异常高的总孔隙率值，并在地层上与位于陆地的高振幅负极（HANP）地震反射器相关。该HANP反射器先前已被解释为多孔流体层，在该层中，由于孔隙压力积累，D {é}碰撞可能会沿边缘的部分发展。我们估算阳离子交换能力（CEC）的粘土结合的水含量，该水含量提供了有关蒙蒂特/伊利石组成和可溶性氯化物含量数据的信息。间质孔隙率对应于从粘土结合水校正的板上总孔隙率，并且在沉积物压实状态和流体流量特性方面更为相关。间质孔隙率与垂直有效应力曲线没有任何计算的证据，并表明第2部分由于高沉积物累积速率而经历了正常的合并。孔隙率单位观察到的孔隙率异常是由于局部出现的含水矿物等出现的，例如蒙脱石，而不是过量的孔隙压力，但是，孔隙压力可能会在盆地中增加更多的土地。我们还使用电阻率模型来估算骨折孔隙度，用于基于有线电阻率对数的先前作品中使用的页岩，并表明裂缝孔隙率在所研究的沉积部门受损部分中产生4-6％的骨折。
In this study, we investigate porosity evolution through the sedimentary input section of the North Sumatra Subduction zone by quantifying interstitial porosity, bound water content and fracture porosity based on IODP Expedition 362 data and post-cruise chemical analyses. During IODP Expedition 362, total porosity of the sedimentary section entering the North Sumatra subduction zone was measured. This total porosity is derived from the total water content of core samples thus including pore water and water bound to hydrous minerals like smectite. Clay mineral composition varies over the sedimentary section and is mainly kaolinite/illite in the Nicobar Fan units and smectite/illite in the prefan pelagic unit below. The prefan pelagic unit shows anomalously high total porosity values and is stratigraphically correlated to a high amplitude negative polarity (HANP) seismic reflector located landward. This HANP reflector has been previously interpreted as a porous fluid-rich layer where the d{é}collement may develop along parts of the margin as a consequence of pore pressure buildup. We estimate clay bound water content from Cation Exchange Capacity (CEC) which gives information about the smectite/illite composition and soluble chloride content data. Interstitial porosity corresponds to onboard total porosity corrected from clay bound water and is more relevant in terms of sediment compaction state and fluid flow properties. Interstitial porosity versus vertical effective stress curve shows no evidence of undercompaction and suggests that the input section 2 has been experiencing normal consolidation due to high sediment accumulation rate. The porosity anomaly observed in the prefan pelagic unit results from the local occurrence of water-bearing minerals like smectite rather than excess pore pressure, which might, however, buildup more landward in the basin. We also estimate fracture porosity using a resistivity model for shales used in previous works based on wireline resistivity log and show that fracture porosity yields 4-6% in damaged parts of the sedimentary section investigated.
