塔中南部坡折带良里塔格组碳酸盐岩溶蚀作用

塔中南部坡折带中2 井良里塔格组岩石组构、阴极发光与扫描电镜及能谱资料的研究表明,岩心残留的孔洞,孔洞中充填的粗大方解石或白云石为碳酸盐矿物溶解再沉淀的产物。良里塔格组底部颗粒灰岩及其晶洞方解石比同期海水Sr 同位素比值偏低,反映了埋藏过程中孔隙流体的低⁸⁷Sr/⁸⁶Sr 比值;顶部颗粒灰岩及其晶洞充填的方解石的Sr 同位素则比同期海水Sr 同位素比值偏高,主要是由于埋藏条件下陆源碎屑(如长石)的溶解所致。晚期充填的方解石脉及溶孔充填方解石的两相盐水包裹体均一温度与盐度分布进一步表明有埋藏胶结与溶解作用。

Carbonate Dissolution of Lianglitage Formation in Southern Slope Break of Tazhong Area

Based on the data of the rock-configuration, cathodoluminescence, scanning electron microscope and energy spectrum of Lianglitage formation in Zhong-2 well located in the southern slope of Tazhong area in Tarim basin, the remaining pores and cavities in the cores are formed by the burial dissolution. And the pores and cavities are corroded and filled with the coarse calcite or dolomite formed by the carbonate mineral's solution and deposition in the burial condition. The ⁸⁷Sr/⁸⁶Sr ratio in the grainstone and calcite in the cavity at the base of Lianglitage formation is lower than that in the seawater at that time, but the ⁸⁷Sr/⁸⁶Sr ratio at the top of Lianglitage formation is higher than that in the seawater because the continental fragment (e.g. feldspar) is corroded. The burial cementation and dissolution are proved by the homogenization temperature and salinity of the two-phase saline inclusion of the late filling calcite vein and pore-filling calcite.