Provenance and depositional systems of the Mesozoic deposits in the Jiyang depression

Provenance analysis of the Mesozoic deposits in the Jiyang depression is based on sandstone and conglomerate contents,stable and unstable mineral contents and trace element distribution patterns.The principal source of the detritus lay to the northwest and southeast.The inner uplifts may provide only part of the detritus to the basin.The alluvial fan-braided stream-braided delta depositional system occurs in the northwest;the alluvial fan-meandering stream(alluvial plain)-delta depositional system appears in the southeast,and the lake depositional system is observed in the central part of the basin.The development of the Mesozoic basin is characterized by large basin,shallow lake,gentle slope and shallow-water delta.