摘要
根据矿物结晶学理论,白云石可按照晶体大小和晶边形貌划分为不同的结构,其结构的演化主要受原岩化学组成、岩石结构和白云岩化流体的影响。白云岩原岩可分为不同化学组分的泥灰岩和含颗粒泥灰岩,泥灰岩可细分为成分均匀的和含溶孔、胶结物的泥灰岩;含颗粒泥灰岩可细分为未接受任何改造的、发生溶蚀胶结作用的和发生泥晶化等作用的含颗粒泥灰岩。以川东北飞仙关组白云岩为例,在不同浓度的白云岩化流体条件中,讨论不同结构白云岩岩石的演化。结果表明:泥晶化及溶蚀作用是白云石岩石结构演化和形成的基础;大多数鲕粒白云岩在低浓度白云岩化溶液中形成;糖粒状白云岩为外来高浓度的白云岩化流体改造形成。
Based on the nucleation and growth kinetics theory,the dolomite crystal can be classified according to crystal size distribution and crystal boundary shape.The evolution of the crystal texture is controlled by the chemical composition and textures of preexisting rock and dolomitic fluid.The preexisting rock can be classified into muddy limestone and muddy limestone with grains.The muddy limestone is classified as the one with uniform composition and the one with dissolved pore and cement.The muddy limestone with grains is classified as that with no alternation,with suffered corrosion and with cementation and micritization.The dolomite crystal textures in Feixianguan Formation of the NE Sichuan Basin can be cited to discuss the classification and evolution of dolomite crystal textures in dolomitic fluid with different concentration.The results show:(1)the corrosion and micritization in preexisting rock is the base of classification and evolution of dolomite crystal textures;(2)most of grains are replaced in dolomitic fluid with low concentration;(3)sucrosic dolomite is formed in foreign dolomitic fluid with high concentration.
出处
《现代地质》
CAS
CSCD
北大核心
2010年第5期945-950,共6页
Geoscience
基金
国家"973"项目(2005CB422105)
关键词
白云石晶体
结构演化
白云岩化流体
川东北
dolomite crystal
texture evolution
dolomitic fluid
northeast of Sichuan Basin