Geochemical Indicators on the Central Tibetan Plateau Lake Sediments: Historical Climate Change and Regional Sustainability

Abstract

This study investigates geochemical indicators (TOC, TN, C/N, δ13Corg, δ15N, and pollen indicators) from sediment samples of Zigetang Co Lake on the Tibetan Plateau (TP) to explore past climate changes in the lake basin. The findings aim to provide essential data for developing sustainable strategies for the TP region. From 14.0 to 10.8 cal. ka BP, the δ15N, TOC, TN, and δ13Corg value of the lake sediments was relatively low; this indicated a low organic matter input into the lake, reflecting a probably cold and arid environment. In addition, the pollen was primarily composed of Artemisia and Gramineae, which are adapted to cold environments, further confirming that the climate during this period was likely cold and dry. From 10.8 to 8.2 cal. ka BP, the changes in the main plant composition were likely due to increased solar radiation, the onset of the monsoon, and higher temperatures and precipitation, which created more favorable conditions for the growth of Cyperaceae. From 8.2 to 4.2 cal. ka BP, when the solar radiation weakened and the monsoon diminished, the basin maintained relatively high water levels, with regional precipitation being likely influenced by westerly winds. From 4.2 to 0.01 cal. ka BP, δ13Corg and δ15N initially decreased and then increased, which was likely a transition from a cold–wet climate to warm–dry conditions during the late Holocene, and the Pollen sum also showed significant changes. Understanding climate evolution and vegetation changes is crucial for formulating timely policies to ensure regional sustainable development.