Geophysical Research Letters ran an article noting the innovative achievements in the study of global changes, plateau ecological landscape and dust accumulation on January 5th, 2022. Professor Lai Zhongping, leading his team of Institute of Marine Sciences, Shantou University, is one of the core authors.

The Tibetan Plateau (TP) is a hotspot of earth system research, and understanding its landscape and ecosystem evolution has been hampered by the lack of time-constrained geological records. Geochronological data from 14 loess sites covering a large region in the Tibetan interior show that the TP loess, rather than accumulating during glacial periods, began aggrading at either 13.4 ± 0.4 or 9.9 ± 0.2 ka. An ecological threshold was crossed, when warmer and wetter conditions resulted in increased vegetarian cover enabling dust trapping. This dust accumulation model is out of phase with that of the Chinese Loess Plateau (CLP) where high sedimentation rates occurred during the cold/dry glacial stages. The TP loess accumulation is in response to global climate change, at both orbital (glacial/interglacial) and millennial (e.g., Younger Dryas event) time scales, despite more complexity via ecological and landscape processes than the CLP loess.

It is very important to understand the processes of landscape and ecosystem evolution in Tibet to adapt to and mitigate the consequences from potential abrupt future climate changes, but not enough well-dated geological records are available. In this study, we present stratigraphic and numerical age results from 14 loess sites covering a large region in the Tibetan interior. Results show that during warm/interglacial conditions of the Holocene and not during the last glacial period when loess aggradation rates in the Chinese Loess Plateau were high. In Tibet, vegetation cover, which was lowered during the last glacial period, increased during Holocene warming allowing for loess accumulation.

Stratigraphic and numerical age data from 14 loess sites covering a large region in the TP enabled us to identify when loess aggradation began and to explore the underlying mechanisms that favored loess accumulation. Results show that the TP loess did not accumulate during the last glacial stage despite the presence of dust in the environment, but began aggrading at either 13.4 ± 0.4 or 9.9 ± 0.2 ka. The basal loess ages are interpreted as the times of dramatic landscape responses to climatic change that resulted in a major increase in vegetation density in favor of loess accumulation. The TP loess was deposited under relatively warm and moist climates, exhibiting a deposition model that is out-of-phase to that of the CLP. Despite being out of phase, loess in the TP and CLP responded to teleconnections associated with late Quaternary Northern Hemispheric climate changes. Unlike the direct link invoked in the CLP between loess deposition and Asian monsoonal precipitation, the TP loess aggraded due to vegetation cover changes driven by climate.