三塘湖盆地中二叠统芦草沟组白云岩成因

Origin of Dolostone in Lucaogo Formaion of Middle Permian in Santanghu Basin

State Key Labortory of Continantal Dynamics, Department of Geology, Northwest University, Xi'an, Shaanxi 710069, China

摘要: 三塘湖盆地中二叠统的芦草组碳酸盐岩是盆地内重要的储集岩之一,碳酸盐岩中50%以上为白云岩。有纹层状白云岩和斑块状白云岩两种,前者白云石自形程度较好;后者白云石为含铁白云石交代方解石而成,铁白云石晶体粗大,自形程度差,其形成时间晚于纹层状铁白云石。白云岩的Mg/Ca值均小于1;Sr的含量为31×10^-6～527×10^-6,平均为217.8mg/kg;方解石和白云石的δ¹⁸O差值大多数小于6%;芦草沟组膏岩并未普遍存在,盐度指数Z平均为124.43。通过对上述特征综合研究认为,三塘湖盆地中二叠统的芦草组白云岩为混合水成因,并建立了相应的白云石化模式。
- 三塘湖盆地 /
- 中二叠统 /
- 白云岩成因 /
- 白云石化模式
Abstract: Carbonate rock of Lucaogou Formation in Middle Permian is a major reservoir rock in Santanhu Basin and dolost one accounts for more than 50% in composition of the carbonate rock.There are two types of dolo stone,one is the bedded dolostone and the other is the patch dolomite.In the bedded dolostone,the mineral dolomite has a good idiomorphism;on the contrary,in the patch dolostone,the idiomorphism of dolomite is not good.The patch dolostone is composed of ankerite with crassitude crystal replacing calcite.
- Santanghu basin /
- middle permian /
- dolostone origin /
- dolomitization model