The Jixianian Carbonate Tidal Flat Sediments on the Southern Margin of the North China Plafform(Shanxi)

The Jixianian strata are well-developed on the southern margin of the North China platform(Shanxi), including, from the Changchengian Gaoshanhe Group upwards, the Shizhuang, Longji-ayuan, Xunjiansi, Duguan and Fengjiawan Formations which are essentially composed of a suit of the carbonate rocks, with a total sedimentary thickness of 1746.7 metres.
The Jixianian carbonate tidal flat sediments which are well-developed and widely distributed in the study area consist of a suit of the upwards-shalfowing lithologic sequences such as stromatolitic sequence and granular sequence which form characteristic sedimentary sequences, as shown by the abundant data. On the basis of the occutrence of the rock and stromatolite associations in the Jixia-nian Shizhuang, Longjiayuan and Xunjiansi Formations, the sedimentary rhythms of A,B and C types have been identified, resulting in the understanding of the regularity of the sediment development in the revalent strata.
The study area once acted as a most important depositional centre on the North China platform during the Jixian period. The long-term constant subsidence and compensation were responsible for the development of the carbonate tidal flat sediments. It seems that these sediments were formed in the tidal epicontinental seas on the ancient continental margins.