Redefinition of Jurassic strata in northeastern Shanxi and its tectonic implications

Abstract: Based on regional stratigraphic correlation and using zircon dating method of tuff and volcaniclastic rocks in the Jurassic stratigraphic sequence, the authors re-divided and defined Jurassic stratigraphic sequence. Some conclusions have been reached: (1) The stratigraphic age of Yongdingzhuang Formation in Ningwu-Jingle basin is identified as the lower Jurassic; (2) The middle Jurassic Tianchihe Formation may be compared to Anding Formation of Ordos basin, and therefore the stratigraphic age of Anding Formation in the controversy should be redefined to the middle Jurassic; (3) The Tiaojishan Formation is redefined to the middle Jurassic in Huyuan basin, this stratum has the diachronistic nature in the Yanshan orogenic belt; (4) The sedimentary time of basal conglomerate of Yaopo Formation in Guangling basin can be equivalent to Nandaling Formation of Yanshan orogenic belt, the basal conglomerate should be the product of tectonic movement in early Jurassic and early middle Jurassic. By the redefinition and redivision of Jurassic stratigraphic sequence in northeastern Shanxi, the angle disconformity between 159.0Ma and (152.77±0.63) Ma is confirmed, and this is dynamically associated with distant field effects produced by synchronous convergences toward the East Asia continent of different plates (Siberia, Paleo-Pacific, Tethys).