Sedimentary characteristics and environments of the Guanzhuang Group in southwestern Shandong

The Upper Cretaceous-Eocene Guanzhuang Group is well developed in southwestern Shandong. The previous studies were once concentrated mainly in stratigraphic division and correlation, and scarcely in sedimentary environmental analysis. The present paper focuses on the sedimentary characteristics and environments of the Guangfuzhuang-Tiaogou section in the Pingyi Basin on the basis of petrological and geochemical examination. In the Guanzhuang Group, there occur the continental fluviolacustrine clastic rocks in the Gucheng Formation; shallow lacustrine carbonate rocks and evaporates in the Bianqiao Formation; littoral-shallow lacustrine carbonate rocks in the Changlu Formation, and pediment fluvial fan deposits in the Zhujiagou Formation. The carbonate rocks in the Bianqiao and Changlu Formations were laid down in the highly saline and highly evaporative continental salinized lake environments. The depositional cycles in the Guanzhuang Group are generally controlled by the multiphase faulting of the Mengshan fault and palaeoclimatic changes.