古环境研究室知识库

Extensive lacustrine deposits in the eastern Tarim Basin provide records of climate change influenced by the westerly winds and the Asian monsoon. To characterize the evolution of climate change in this region, we analyze elemental concentrations of barium (Ba) from the Ls2 drill core of Lop Nor, a paleo-lakebed located in the eastern Tarim Basin. Biogenic Ba concentrations from this drill core display a large-amplitude oscillation that generally follows a pattern similar to that of Artemisia content and ostracod assemblages, suggesting that is may serve as an index for climate change experienced in the basin. Our results indicate that biogenic Ba is especially sensitive to precipitation. All climatic proxies served in this study vary significantly over late Miocene to early Pleistocene time period. Strong aridification of eastern Tarim in the late Miocene to the early Pliocene may be attributed to a latitudinal shift in the westerly winds, which would have resulted in more moisture transported to southern and eastern Tibet. The growth of the Himalaya and Tibetan Plateau may have acted as an orographic barrier that blocked moisture sourced in the south from the northern margins of the plateau. We link weaker aridification in the late Pliocene to an increased intensity of the Indian Monsoon.