西藏羌塘盆地东部中侏罗统混合沉积层序地层学研究  

An analysis of mixed silicic clastic and carbonate sedimentary sequence in the Middle Jurassic strata in the eastern part of the Qiangtang basin,Tibet

作　　者：杨莉[1] 马伯永[2] 李尚林[3] 王根厚[4] 

机构地区：[1]中国地质图书馆,北京100083 [2]中国地质调查局,北京100047 [3]中国地质调查局西安地质调查中心,陕西西安710054 [4]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《中国地质》2015年第4期1037-1045,共9页Geology in China

基　　金：国家自然科学基金项目(40172014);青藏高原1:25万仓来拉幅区域调查项目(I46C004003)资助

摘　　要：西藏羌塘盆地东部中侏罗统广泛发育陆源碎屑与碳酸盐的混合沉积。综合前人研究成果,结合区域地质资料和室内样品分析,本文对陆源碎屑岩、碳酸盐岩、混积岩及混积层系,混合层序地层进行了详细研究。研究结果表明,混合沉积在微观上表现为陆源碎屑与碳酸盐沉积物组分的混积岩,宏观上则表现为陆源碎屑岩、碳酸盐岩、混积岩相互叠加的混积层系,发育滨岸、碳酸盐岩缓坡、潮坪-溻湖、三角洲等沉积体系。运用层序地层学原理将中侏罗统划分为SQ1-SQ4四个三级层序,提高了研究区层序地层划分精度;探讨了混合沉积与层序地层的对应关系。总体上看,以陆源碎屑沉积为主的沉积背景下,混合沉积主要发育在海侵体系域的早期和高位体系域的晚期。以碳酸盐沉积为主的沉积背景下,混合沉积主要发育在海侵体系域的早期和高位体系域的晚期。Mixed silicic elastic and carbonate sedimentary sequence is developed extensively in the east basin of Qiangtang. On the basis of previous researches, the authors studied carbonate and silicic clastic mixed rock, mixed layer system and mixed sequence by means of the analysis of regional geological materials and samples. The results show that the study area is characterized by interactive sediments of silicic elastic rock and carbonate rock at the microscopic level. And in the macro-performance of the mixed sequence which composed of silicic elastic rock, carbonate rock and mixed rock. Mixed sedimentation mainly occurred in the sedimentary system of shore, carbonate slump and tidal fiat-lagoon and delta. The middle Jurassic can be divided into four sequences of SQ1-SQ4. The authors investigated the relationship between mixed sedimentation and sequences and found that, on the whole, under the circumstance of dominated silicic elastic rocks, mixed sedimentation mainly occurred at the early stage of TST and the late stage of HST, whereas under the circumstance of dominated carbonates, mixed sedimentation mainly occurred at the early stage of TST and the late stage of HST.

关 键 词：侏罗系 混合沉积 体系域 层序地层格架 羌塘盆地 

分 类 号：P534.52[天文地球—古生物学与地层学]