湖北随州上震旦统灯影组白云岩成因

湖北随州薛家店灯影组为一套斜坡-盆地相碳酸盐岩沉积。该区白云岩极为发育,白云岩中白云石晶粒细小、晶形差；白云岩横向分布稳定,并且水平纹层发育。碳氧同位素和包裹体分析表明,该区古盐度值随水体深度增加而逐渐变低。白云岩为准同生期白云石化产物,其Mg²⁺来源与顺斜坡向下流动的高盐度卤水流的活动有关,据此归纳出该区白云石化作用的模式。

ORIGIN OF DOLOMITES IN DENGYING FORMATION, UPPER SINIAN,SUIZHOU,HUBEI

The Late Sinian Dengying Formation at Xiejiadian in Suizhou,Hubei Province is dominated by deep-water carbonate deposits of slope basin facies.Dolomitas develoved well in study area,and are characterized by fine crystals,poor crystal forms,stable lateral distribution and well horizontal lamination.The isotope analysis of carbon and oxygen show that the salinity decreases with the increase of water depth,indicating that the dolomites were the products of penecontemporaneous dolomitization,the Mg