Echo of the Younger Dryas in Holocene Lake Sediments on the Tibetan Plateau. Issue 20 (23rd October 2018)

• Record Type: Journal Article
• Authors: Ramisch, Arne; Tjallingii, Rik; Hartmann, Kai; Diekmann, Bernhard; Brauer, Achim
• Is Part Of: Geophysical research letters. Volume 45:Issue 20(2018)
• Page Start: 11, 154
• Page End: 11, 163
• Publication Date: 2018-10-23
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2018GL080225
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Reading the sediment record in terms of past climates is challenging since linking climate change to the associated responses of sedimentary systems is not always straightforward. Here we analyze the erosional response of landscapes on the Tibetan Plateau to interglacial climate forcing. Using the theory of dynamical systems on Holocene time series of geochemical proxies, we derive a sedimentary response model that accurately simulates observed proxy variation in three lake records. The model suggests that millennial variations in sediment composition reflect a self‐organization of landscapes in response to abrupt climate change between 11.6 and 11.9 ka BP. The self‐organization is characterized by oscillations in sediment supply emerging from a feedback between physical and chemical erosion processes, with estimated response times between 3, 000 to 18, 000 years depending on catchment topography. The implications of our findings emphasize the need for landscape response models to decipher the paleoclimatic code in continental sediment records. Plain Language Summary: Lake sediments are an important source of information on past climates. Reading the information is not always straightforward. Complex interactions in landscapes can affect the transmission of climatic signals to the sediment record. However, the exact nature of such complex interactions remains unknown. This study compares sediment deposits of three lakes on the Tibetan Plateau. The deposits are continuous records of landscape responses to climate change during the last 12, 000 years. We identified a mathematical model that accurately simulates changes in sediment composition at all sites. The model simulations suggest that an abrupt warming at the end of the last glacial period destabilized the landscapes. This caused fluctuations in the transport of sediments, which persisted for several thousand years. Our findings present evidence for a long‐lasting impact of abrupt climate change on fundamental Earth surface processes. Key Points: We analyzed the propagation of climatic signals to Holocene sediment records of three well‐studied Tibetan lakes in a dynamical system framework Holocene variation in geochemical proxies mainly reflect site‐specific landscape responses to abrupt climate change Our results indicate a feedback between physical and chemical erosion processes on interglacial timescale