An intermontane desert system: Sedimentology, mechanism, and provenance in Southeast China during the Late Cretaceous

Abstract

Along with the intensification of global warming, severe desertification has already impaired human sustainable development. In a near-future greenhouse world, the total area of the desert will increase, and new types of deserts may emerge. During the “greenhouse” Cretaceous, conventional large paleo-deserts developed in broad topographic basins, and many possible deserts developed in small-scale intermontane basins, which are unusual in near-modern times and less studied. A comprehensive study of their sedimentology, mechanisms, and provenance would refine our interpretation of desertification and improve our understanding of the potential impact of future climate in arid and semi-arid regions in a near-future “greenhouse” world. The Xinjiang Basin is a typical intermontane basin in Southeast China that formed >300 m of successive aeolian deposits during the early Late Cretaceous, making it an ideal place to investigate the Sedimentological characteristics and formation mechanisms of intermontane deserts. In this study, we applied detailed sedimentary analyses to the aeolian deposits throughout the Xinjiang Basin and reconstructed a three-dimensional sedimentary model for the intermontane deserts. We confirmed the existence of the typical intermontane paleo-desert and summarized in detail the differences between intermontane deserts and broad topographic deserts. We noticed that the “greenhouse” state during the Late Cretaceous seems to have been suitable for the development of deserts in intermontane basins due to the hot, arid climate conditions and penetrating winds with sufficient transport capacity. In addition, the provenance analysis of the intermontane desert proved the ultra-long-distance aeolian sediment transport, and it may enable by the strengthening of intermittent westerly winds during short-lived glacial episodes and the presence of a low-relief corridor that served as a transport pathway from source to sink. Therefore, we suggest the emergence and development of intermontane deserts in a near-future “greenhouse” world would contribute to the global desert expansion and massive desertification.