苏皖北部新元古界臼齿碳酸盐岩脉类型及其形成机理  

The Neoproterozoic molar-tooth carbonate rock veins in northern Anhui and Jiangsu Provinces and their forming mechanism

作　　者：贾志海[1] 宁霄峰[1] 洪天求[1] 郑文武[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《古地理学报》2011年第6期627-634,共8页Journal of Palaeogeography：Chinese Edition

基　　金：国家教育部博士点基金项目(编号:20070359019);国家自然科学基金项目(编号:40902096)共同资助

摘　　要：苏皖北部新元古界碳酸盐岩地层中广泛发育臼齿碳酸盐岩脉体。根据这些脉体的产出特征,将其划分为两大类型。类型1主要产出于新元古界下部的刘老碑组、九里桥组和倪园组中,多形成于沉积期,脉体杂乱分布且与叠层石透镜体、砾屑、滑塌构造、冲刷沟槽、透镜状交错层理等共生。类型2主要产出于新元古界中、上部九顶山组、张渠组、魏集组和望山组中,多形成于成岩早期,脉体分布具有规律性,产出地层有明显的粒序层理,与上下岩层间具有明显的冲刷界面,并形成规模不一的韵律层。臼齿脉体形成的原动力可能与超级大陆Rodinia的裂解导致的地壳运动有关。类型1形成于瞬间动荡的环境,可能指示了Rodinia裂解的序幕,类型2形成于稳定的、周期性变化的环境,可能指示了Rodinia裂解过程中地应力的周期性释放过程。Molar-tooth carbonate rock veins are abundant in the Neoproterozoic carbonate rocks in northern Anhui and Jiangsu Provinces. According to their features in different strata, two types of molartooth carbonate rock vein can be identified. Type 1, mostly disorderly outcropped, coexisted with stromatolite bioherms, gravels, debris, slump structures, swash channels and hummocky cross-beddings, were formed in the upper Liulaobei, Jiuliqiao and Niyuan Formaitons which belong to the Lower Neoproterozoic. Type 2, which were stably outcropped in widely spread rhythmic units with graded beds and typical erosion surfaces, were outcropped in other formations which belong to the Upper Neoproterozoic. The initial forming power of the molar-tooth carbonate rock veins might be the crustal movements which were caused by the break-up of the Rodinia. Type 1 was formed in tempestuously changing environments during the depositional period, and might be a prelude signal of the Rodinia＇s break-up, while Type 2 was formed in steadily, periodically changing environments during the early diagenetic process, might indicate that the intermittent release of the earth stress during the break-up period of the Rodinia

关 键 词：臼齿碳酸盐岩脉 新元古界 形成机理 苏皖北部 

分 类 号：P588.245[天文地球—岩石学]