沉积学报2023，Vol.41Issue(6)：1673-1680,8.DOI:10.14027/j.issn.1000-0550.2023.124
南京地区早三叠世碳酸盐沉积动力过程初探
Preliminary Study on Sediment Dynamic Processes of Early Triassic Carbonate Deposits in Nanjing Area,Eastern China
摘要
Abstract
[Objective]Early Triassic carbonate deposits indicate the dramatic change of sedimentary environment after the Permian mass extinction.However,the main difficulties in obtaining sedimentary environment information by sediment dynamics lie in the difficulties in field observation,unknown initial and boundary conditions,and un-known source and transport direction of sediments.One of the new approaches is to reconstruct the governing equa-tions according to the complex system theory to achieve the goal of reliable simulation.[Methods]Here a method for calculating sedimentary environment parameters is established to analyze the sedimentary record of the Early Triassic(Helongshan Formation)carbonate deposits in the Nanjing area,which contain 24 mud-carbonate cycles.[Results and Discussions]The preliminary results show that the cyclic deposition has a vertical scale of 100-102 cm,the car-bonate and the muddy layers appear alternately,the sedimentary structure is characterized by laminae,and the thick-ness of the carbonate deposit accounts for 74%in the 24 cycles.The time scale of each cycle is 5-40 ka,as calculated according to the deposition rate of the mud layers.Although the thickness of the mud layers only accounts for 26%of the total thickness,it accounts for 73%of the total temporal duration.The environmental parameters,such as deposi-tion rate,vertical settling flux,suspended sediment concentration,carbonate and biological production,are similar to those of the present deep-sea carbonate sedimentary environment.[Conclusions]Cyclic sedimentation reflects the characteristics of paleo-marine environment and climate change in this region,but the further improvement of the cal-culation method depends on the definition of the constraining conditions associated with the impurity content of car-bonate,the thickness and preservation potential of laminae,and the production of sediment and organic matter with-in the water column.关键词
碳酸盐沉积/早三叠世/动力过程/周期性/沉积速率/南京地区Key words
carbonate deposits/Early Triassic/dynamic processes/cyclicity/deposition rate/Nanjing area分类
天文与地球科学引用本文复制引用
高抒..南京地区早三叠世碳酸盐沉积动力过程初探[J].沉积学报,2023,41(6):1673-1680,8.基金项目
国家自然科学基金项目(41530962)National Natural Science Foundation of China,No.41530962 （41530962）
