Chinese scientists have reconstructed the uplift history and environmental changes of the Luolong Basin in eastern Xizang autonomous region from 54 million to 43 million years ago, helping better understand the growth process of the Qinghai-Tibet Plateau and the interactions between deep earth dynamics and surface environments.
Between 54 million and 46 million years ago, the Luolong Basin was only 600 meters above sea level. By 44 million years ago, the basin rapidly rose to about 2,900 meters, resulting in increased rainfall and the emergence of distinct wet and dry seasons, said Zhao Chenyuan, the first author of the study and a PhD student at the Institute of Tibetan Plateau Research, Chinese Academy of Sciences.
The research was published in the National Science Review journal last month.
"The ecological environment of the Luolong Basin before 44 million years ago was similar to today's Shangri-La in Yunnan province, with mountains and forests intertwined, rich biodiversity and an annual precipitation of nearly 1,500 millimeters, resembling the forest ecosystems of modern Yunnan and Southeast Asia," Zhao said.
"At that time, there were large lakes and rivers in the basin. During wet periods, the lakes might have been as beautiful as today's Dianchi Lake in Kunming or Erhai Lake in Dali, Yunnan. The lakes likely hosted primitive freshwater fish and abundant insects," she added.
The research team, led by Academician Ding Lin from the Institute of Tibetan Plateau Research, conducted multiple field geological investigations in the region from 2020 to 2024, collecting a large number of volcanic ash, paleosol and fossil samples.
Ding, the corresponding author of the study, said that the Luolong Basin is located in a transitional zone connecting the central and eastern parts of the Qinghai-Tibet Plateau, making it a key area for studying plateau uplift and climate response.
"This discovery updates the spatial distribution of the Central Tibetan Valley, extending it from the central plateau to the broader eastern Xizang region, forming a biodiverse forest belt 44 million years ago," he said.
Zhao noted that this finding also provides new evidence for understanding the uplift process of the Qinghai-Tibet Plateau, helping us understand how surface changes on Earth respond to deep dynamic processes.
"Following the collision of the Indian and Eurasian plates, there is a low-elevation Central Tibetan Valley between the Gangdese and Tanggula mountains. Our findings reveal that the surface uplift of eastern CTV occurred before that of central CTV. The topography of the CTV was characterized by a westward-sloping configuration, beginning higher in the east and gradually lowering to the west," she said.
"To investigate the uplift mechanisms of the central valley, we synthesized geophysical and magmatic evidence within the region. Our analysis suggests that the uplift of this valley was likely controlled stepwise delamination of the subducted Lhasa lithosphere from east to west, accompanied by asthenospheric upwelling," Ding explained.
Additionally, the topographic changes caused by the plateau's uplift have significantly influenced the Asian monsoon system. "Studying these changes offer important clues to climate change in East Asia," Ding said.
