Sedimentary characteristics of the Ordovician limestone deposit in the Jingyang-Chunhua region, Shaanxi

The Ordovician strata in the Jingyang-Chunhua region, Shaanxi may be grouped into four formations, from the base upwards including Sanshanzi, Jiawang, Majiagou and Taoqupo Formations. The carbonate rocks more than 1000 m in thickness in the upper member of the Majiagou Formation are very pure, with the average CaO contents of more than 54%, and average MgO contents of less than 1%. These carbonate rocks constitute the extralarge limestone deposit which is unmatchable on the North China platform.