古地理学报2012，Vol.14Issue(4)：461-476,16.
塔东北库鲁克塔格地区中上寒武统白云岩类型与孔隙演化
Types of dolostones and pore evolution of the Middle and Upper Cambrian in Kuruk Tag area of northeastern Tarim Basin
摘要
Abstract
In a geological analogous study, the Middle and Upper Cambrian rocks from the northern Xingde fault of the Kuruk Tag area, northeastern Tarim Basin, were systematically investigated. These rocks consist of shallow marine platform carbonate rocks, with extensive dolomitization, and show significant differences from the Cambrian hydrothermal dolostones ( HTD) in the Western Canada Basin. The Canadian dolostones are genetically related to fractures and breccia zones partially to completely including the fractures and presumably formed due to hydrothermal fluids expelled from the Rocky Mountain fold-and-thrust belt during the Laramide orogen. In contrast, the hydrothermal dolostones (HTD) in the studied Tarim Basin were formed as the result of hydrothermal fluid infiltration and alteration associated with deep-burial diagenesis, possibly controlled by recirculation of formation water in the strike-slip fault zones during the Late Permian ( Late Hercynian) in northeastern Tarim Basin. According to the texture, six types of dolostones can be differentiated, including: (1) silt-sized dolostone, (2) fine-medium crystalline dolostone, (3) medium-coarse crystalline dolostone, (4) fine-crystalline dolostone with bright rims and dark cores, (5) saddle dolostone and (6) fracture and vug-lining dolostones, coarse or saddle dolostones. These dolostones form a complete sequence of diagenesis, starting with dolomicrite, and fine-medium crystalline dolostone as the early replacement of calcilutite at shallow-burial, followed by coarse and heterogeneous medium-coarse crystalline dolostone as the result of recrystallization at elevated temperatures in deep-burial, and then saddle dolostone and fracture and vug-lining coarse or saddle dolomite precipitated directly from re-circulated hot formation water. The HTD identified in the Tarim Basin samples display distinct coarse non-planar sucrosic textures, with few intracrystalline pores, intercrystalline dissolution pores. At least four period of fissures, dissolution, cementation, or filling, have been recognized , with the earlier fractures being filled with the late dolostone, partly precipitated dolostone, quartz, bitumen-bearing barite and anhydrite. While the pore development during deep burial has been controlled by original-bedding, fault-fissure, diagenesis, infiltration and hydrothermal alteration process, the later exposure to meteoric water may have been important for the late diagenetic pore system related to dolomitization.关键词
白云岩类型/成岩作用/孔隙类型/热液白云岩/寒武系/塔里木盆地/加拿大西加盆地Key words
dolostone types, diagenesis, pore types, hydrothermal dolostone, Cambrian, Tarim Basin , Western Canada Basin分类
天文与地球科学引用本文复制引用
钱一雄,陈代钊,尤东华,卿海若,何治亮,董少峰,马玉春,焦存礼,田蜜..塔东北库鲁克塔格地区中上寒武统白云岩类型与孔隙演化[J].古地理学报,2012,14(4):461-476,16.基金项目
国家"973"项目(编号:2012CB214802)与国家重大专项(编号:2008ZX0502,2008ZX05008-003,2011ZX05005-02)联合资助 （编号:2012CB214802）
