The sedimentological characteristics of the intermontane desert system in the Jurong Basin, South China and its relationship with the Late Cretaceous hot climate

Abstract

As a typical greenhouse period, the Late Cretaceous was characterized by an extremely warm and arid climate. In this period, intermontane deserts were widely distributed in South China, which can be used to inform the evolution of the palaeogeography and palaeo-wind patterns during the hot climate of the Late Cretaceous. The Jurong Basin is located at the eastern margin of South China and close to the palaeo-Pacific Ocean; it has typical aeolian deposits but is hitherto less studied. In this study, four sedimentary facies (aeolian dune, dry/damp/wet interdune, sandsheet, and desert lake facies) and three forms of aeolian dunes (simple, compound, and complex) are identified in the Upper Cretaceous Chishan Formation, confirming the development of an intermontane desert in the Jurong Basin. The dynamic evolution models show that the intermontane desert transitioned from a lacustrine-dominated to an aeolian-dominated system, which indicates a gradual drying trend. We suggest that the development of the Chishan intermontane desert was controlled by the Late Cretaceous greenhouse climate, the accelerated aridification of the subtropical high, and the rainshadow effect of the coastal mountains. Palaeo-wind directions in the Chishan desert show westerlies and possible palaeo-monsoon wind patterns. The input of palaeo-monsoon moisture led to the development of desert lake and damp/wet interdune deposits in the Chishan desert, which indicates that the Jurong Basin might have been on the windward side of the coastal mountains during the Late Cretaceous. Our study extends the eastern boundary of the South China intermontane desert system during the Late Cretaceous.