(Table T1) Density, porosity, void ratio and silica crystallinity index of ODP Site 185-1149 sediments

Siliceous pelagic sediments have been known to be crystallographically altered during burial diagenesis (e.g., Hesse, 1990; Behl and Smith, 1992, doi:10.2973/odp.proc.sr.129.112.1992). In order to know the systematic downhole change of silicification, sediments from Pacific Ocean crust obtained during Ocean Drilling Program Leg 185 Site 1149 (Plank, Ludden, Escutia, et al., 2000, doi:10.2973/odp.proc.ir.185.2000) were analyzed. For collected samples of Early Cretaceous age below the pelagic sediments, which are not as highly silicified, silica mineral crystallization in the siliceous sedimentary rocks is determined by X-ray diffraction (XRD), and the related textural change is shown by using scanning electron microscope (SEM).

已知硅质远洋沉积物在埋藏成岩作用过程中会发生晶体学改造（例如：Hesse, 1990；Behl与Smith, 1992，DOI:10.2973/odp.proc.sr.129.112.1992）。为明确硅化作用的系统井下演化规律，本研究对大洋钻探计划（Ocean Drilling Program, ODP）第185航次1149站位获取的太平洋地壳沉积物开展了分析（Plank、Ludden、Escutia等, 2000，DOI:10.2973/odp.proc.ir.185.2000）。针对远洋沉积物之下的早白垩世未强硅化采集样品，通过X射线衍射（X-ray diffraction, XRD）测定硅质沉积岩中的硅质矿物结晶特征，并借助扫描电子显微镜（scanning electron microscope, SEM）观测相关结构变化。