西沙群岛西科1井第四纪生物礁中典型暴露面的岩石学与孔隙特征

Petrological Charateristics and Pore Types of Quaternary Reef Adjacent Typical Exposed Surface in Well Xike-1,Xisha Islands

根据岩心观察、薄片鉴定和图像分析,对西科1井第四纪发育的典型暴露面及其附近的岩石类型、成岩作用和孔隙类型进行了系统的分析.研究表明：典型暴露面（埋深68.75~70.24m）附近的岩石类型为骨架灰岩和泥粒灰岩,成岩作用类型包括溶解作用、胶结作用、泥晶化作用和新生变形作用,孔隙类型主要为粒间孔和粒间溶孔、粒内孔及粒内溶孔、生长骨架孔及其溶孔、铸模孔和晶间溶孔.碳酸盐矿物的悬垂状产状、生物体腔孔充填物的方解石化和普遍发育的溶解作用指示该深度段遭受了大气水淋滤的强烈改造.

Diagenesis and pore characteristics of Quaternary reef-carbonate adjacent typical exposed surfaces in well Xike-1 have been il- luminated by means of core observation, thin-section rock identification and image analysis. The results show that the rock types around the typical exposed surface in the depth of 68.75--70.24 ro include packestones and grainstone. And associated diagenesis includes disso- lution, cementation, micritization and neomorphism. The pore types identified include intergranular pore, intergranular dissoved pore, intragranular pore, intragranular dissoved pore, skeleton growth pore, skeleton growth dissolution pore, modic pore and intergranular dissolved pore. Drapstone shape of the carbonate mineral, calcite filling in the pore and common dissolution of calcite indicate that the depth section was reformed strongly by the atmospheric water leaching.