Oasis evolution and human activities in the central Tianshan Mountains of the Asian inland arid zone: Provenance and environmental reconstruction

Abstract

The Asian inland arid zone (AIAZ), the largest inland arid region in the world, forms the core area of the Silk Road. Despite its significance, we have limited knowledge about the sediment provenance in the oases and their evolutionary processes. Studying the evolution of oases is crucial for understanding the complex interactions among environmental changes, human history, and survival strategies in the AIAZ. This study provides insights into the interactions between oases and human populations and offers references for future oasis evolution, which is essential for ecological conservation and sustainable development. We investigated three key factors in the peat profile of oasis wetlands in the central Tianshan Mountains of the AIAZ: humification degree, TOC and grain size. Our goal was to identify the sediment provenance of the oases, reconstruct the sedimentary environment and evolutionary processes, and explore the relationship between the oases and human activities. Our results indicate that the sediments in the oasis wetlands of the central Tianshan Mountains primarily originate from the Kurban Tonggute Desert, the Gobi Desert in the intermountain basins, the Baiyang River floodplain, and weathered debris from the mountains brought about by glacial snowmelt. The transport of these sedimentary materials is primarily driven by wind and water. Oasis evolution is largely influenced by warm season temperatures and recharge from glacial snowmelt. Oases expand with increased glacial snowmelt recharge and contract when it decreases. The intensity of human activity has been closely related to the evolution of oases, as they provide crucial survival sites and resources for humans in arid zones. However, the ecology of these oases faces significant challenges due to global warming and intensified human activities. This paper proposes a series of measures based on our understanding of oasis evolution and sediment sources to provide a reference for oasis conservation and sustainable development.