摘要
湖南石门杨家坪下寒武统杷榔组三段发育陆源碎屑与海相碳酸盐的混合沉积。综合前人研究成果,通过对研究区野外露头资料的详细观测和室内样品分析及数据统计等工作,对研究区杷榔组三段混合沉积进行了详细的研究。研究区混合沉积特征宏观上表现为由陆源碎屑与混积物交互沉积、碳酸盐与混积物交互沉积和不同类型混积物本身的交互沉积构成的混积层系,微观上表现为陆源碎屑组分与碳酸盐组分混合沉积所形成混积岩;混合沉积类型主要为内潮汐沉积作用和浊流沉积作用形成的复合式混合沉积Ⅱ,次为深水原地沉积作用形成的渐变式混合沉积,但是不同成因的沉积作用形成的混合沉积类型往往叠加在一起,形成复合式混合沉积Ⅱ+渐变式混合沉积的混合沉积复合体;混合沉积环境为深水斜坡,发育内波、内潮汐混合沉积微相、深水原地混合沉积微相和远源浊流混合沉积微相等类型;在沉积环境分析的基础上,根据内波、内潮汐沉积特征,剖析了混合沉积的沉积机理;结合混合沉积的成因、沉积机理、产出部位及沉积环境等因素,以沉积学原理为指导,建立了研究区杷榔组三段的混合沉积模式。
Mixed deposits, which is composed of terrigenous fragment and carbonate of marine facies, develops extensively in the Lower Cambrian Balang Formation at Yangjiaping, Shimen, Hunan Province. Synthesized he previous studies, on the basis of studying the abundant outcrops and the data count to observe detailedly and interior data samples, carried out detailed research on the mixed deposits of the study area. In the study area, the macroscopic characteristics of mixed deposits are interbeded between terrigenous fragment and the mixed sediments, between carbonates and he mixed sediments, between different type mixed sediments in high frequency. The microcosmic characteristics of mixed deposits are showed the form of the mixed rocks, which is composed of terrigenous fragment constituent and carbonateconstituent of one layer. Mixed sedimentary type can be divided into complex mixed deposit Ⅱ and blended mixed deposit,which is often effected by the deposition. The complex mixed deposit Ⅱ is born of deposition of internal -tide and turbidity current, the blended mixed deposit is born of deposition of deepwater in situ. The study area sendimentary was a deepwater slope environment, there were sedimentary tiny facies of internal-wave and internal-tide, sedimentary tiny facies of deepwater in situ and sedimentary tiny facies of turbidity current,etc; On the basis of the depositional environment, in virtue of the detailed analysis of thedeposition characteristics of the internal-wave and internal-tide, the deposition mechanism could be analysed in detail In virtue of the analyses the cause of the mixed sedimentation, deposition mechanism, location developing, deposition environment, etc, being guided by study of deposition principles, the mixed sedimentary model of the mixed deposits was established.
出处
《地质论评》
CAS
CSCD
北大核心
2008年第5期593-601,共9页
Geological Review
基金
国家自然科学基金(编号40672071)的成果。
关键词
下寒武统
杷榔组
混合沉积
湖南
Hunan province
the Lower Cambrian
Balang Formation~ mixed sedimentation
