Depositional Character and Influencing Factors of Fine-Grained Gravity Flow of Chang 73 Submember in Longdong Area of Ordos Basin
Jiang Wenqi
Feng Youliang
Zou Caineng
Dong Lin
Yang Zhi
Zhang Hong
Wang Xiaoni
You Yuan
Zhang Tianshu
Wei Qizhao
Fan Yuchen
Abstract：To examine the fine-grained gravity flow sedimentation of the Chang 73 submember in the Longdong area,Ordos basin,through observation of core and thin sections,XRD analysis,and trace elements analysis,the sedimentary characteristics and influencing factors of fine-grained gravity flow sedimentation were studied.7 lithofacies assemblages were formed due to different depositional processes:the shale with lamina tuffaceous assemblage,the fine-grained turbidity currents to mud flow assemblage,the transitional flow to mud flow assemblage,the slump to debris flow to mud flow assemblage,the surge-like turbidity flow assemblage,the quasi-steady turbidity current assemblage,and the concentrated density flow assemblage.The development of fine-grained gravity flow is mostly controlled by tectonic activities,paleo-climate change,and paleo-topography of the lacustrine basin.Tectonic activities are the key factors in inducing the development of slump-triggered fine-grained gravity flow sedimentation,while flood events promote the development of flood-triggered fine-grained gravity flow sedimentation.The characteristics of the paleogeomorphology have a significant control effect on the distribution of fine-grained gravity flow sedimentation,the gradient of the slope significantly influences the depositional characteristics of slump-triggered fine-grained gravity flows.
Keywords：fine-grained gravity flow sedimentationOrdos basinYanchang Formation Chang 73 submemberdepositional characteristicsinfluencing factorpetroleum geology
Publication Date：2025-06-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：18( 2209-2226 )