106 / 2022-02-16 18:19:58

川东北地区早中侏罗世沉积环境、物源变化及其构造意义

heavy mineral composition, zircon U-Pt age, paleocurrent direction, Micang Mountain, Daba Mountain

detailed sedimentary description was conducted for the lower-middle Jurassic formations on Tieshan field profile, near Dazhou northeastern Sichuan Basin. Sedimentary environment, provenance property and their coupling relationship were studied. Sedimentary facies description, paleocurrent direction, heavy mineral composition and detrital zircon U-Pt ages were analyzed in this study. Results show that the Zhenzhuchong member is characterized by sufficient debris sources supply and is dominated by fluvial-delta environment. From the Dongyuemiao to lower Lianggaoshan formation the study area was dominated by lacustrine deposits. Supply of debris sources significantly increased from the middle Lianggaoshan member accompanied by paleocurrent direction change and lake shrinkage. Comprehensive analysis on provenance indicated changes in provenances were related to environment changes. Both of them were controlled by orogenesis around the basin. Inferred from the characteristics of zircon age distribution the provenances change at the end of Ziliujing Formation, middle of Lianggaoshan Formation and end of Lianggaoshan Formation is respectively resulted from uplifs of Micang Mountain, Daba Mountain and Qinling Mountain.