“…However, this phase of high activity is hardly preserved in the sedimentologic record because of the constant reworking of the deposits. Few ages are available from sections, which have been protected by a sediment cover or because of a sheltered topographic position (Stauch et al, 2017). In a recent review, Li and Yang (2016) compiled ages available in the INQUA Dune Database (state: 2013) from the deserts of northern China.…”
Section: Discussionmentioning
confidence: 99%
“…Therefore, aeolian processes, presumably dominant on large parts of the northeastern TP, have not been preserved as aeolian landforms (e.g., dune fields, sand sheets), despite sufficient sediment supply, transport capacity, and a large sediment availability. Only in few locations, where sediments were protected from deflation, did the proxy record survive (Stauch et al, 2017). Figure 4(colour online) Conceptual model of the interpretation of optically stimulated luminescence ages from aeolian sands on the northeastern Tibetan Plateau.…”
Section: Discussionmentioning
confidence: 99%
“…The data are based on the significantly expanded and updated database published by Stauch (2016). The new data set (see the Supplementary Materials) comprises 232 OSL ages from sand deposits (Liu et al, 2011, 2012, 2013; Lu et al, 2011, 2015; Stauch et al, 2012, 2016, 2017; Yu and Lai, 2012, 2014; Zhou et al, 2012; Qiang et al, 2013a, 2016; Yu et al, 2013; Lehmkuhl et al, 2014; Hu et al, 2017). The aeolian sand deposits include dunes, sand sheets, and sandy sediments intercalated in loess deposits and fluvial or lacustrine sediments.Figure 2Optically stimulated luminescence (OSL) ages of sand deposits on the northeastern Tibetan Plateau for the last 30 ka.…”
Section: Methodsmentioning
confidence: 99%
“…Aeolian sediments are widespread on the northeastern TP and range from a thin loess cover to fully developed dune systems (e.g., Lehmkuhl, 1997; Lehmkuhl and Haselein, 2000; Sun et al, 2007; Lehmkuhl et al, 2014; Nottebaum et al, 2014; Dong et al, 2017). The main sediment sources are glacial outwash plains (e.g., Sun et al, 2007; Smalley et al, 2014), fluvial deposits, exposed lake beds (Lehmkuhl and Haselein, 2000; Kaiser et al, 2010; IJmker et al, 2012; Yu et al, 2015; Qiang et al, 2016), and older aeolian archives (Stauch et al, 2017). The aeolian system probably is not supply limited because abundant, thick Quaternary valley fill deposits throughout northeastern Tibet can be readily reworked.…”
Different interpretations of accumulation and preservation of aeolian sediments lead to divergent and sometimes contradictory palaeoclimate reconstructions. Although aeolian transport mainly occurs during dry climate, the preservation of the aeolian sediment is a critical factor in many environments in determining the nature of the aeolian sedimentary archive. Analysis of more than 200 optically stimulated luminescence ages for aeolian sands from Tibet shows four different aeolian phases of accumulation. Strong aeolian activity occurred during the last glacial maximum, but hardly any aeolian sediments are preserved. Consequently, the period with the highest aeolian activity is not recorded in the sedimentary record. A phase of aeolian accumulation occurred in the late glacial and the early Holocene. The duration of deposition for this phase is a consequence of the complex topography and an increase in moisture. This phase was punctuated by exceptionally strong accumulation during the Younger Dryas stade. The mid-Holocene is characterised by weak aeolian accumulation and fluvial erosion caused by greater precipitation during the maximum height of the Asian summer monsoon. Aeolian activity resumed in the late Holocene because of drier conditions. The conceptual model provides an approach that can be applied to other mountain and desert margin regions that have limited sediment availability.
“…However, this phase of high activity is hardly preserved in the sedimentologic record because of the constant reworking of the deposits. Few ages are available from sections, which have been protected by a sediment cover or because of a sheltered topographic position (Stauch et al, 2017). In a recent review, Li and Yang (2016) compiled ages available in the INQUA Dune Database (state: 2013) from the deserts of northern China.…”
Section: Discussionmentioning
confidence: 99%
“…Therefore, aeolian processes, presumably dominant on large parts of the northeastern TP, have not been preserved as aeolian landforms (e.g., dune fields, sand sheets), despite sufficient sediment supply, transport capacity, and a large sediment availability. Only in few locations, where sediments were protected from deflation, did the proxy record survive (Stauch et al, 2017). Figure 4(colour online) Conceptual model of the interpretation of optically stimulated luminescence ages from aeolian sands on the northeastern Tibetan Plateau.…”
Section: Discussionmentioning
confidence: 99%
“…The data are based on the significantly expanded and updated database published by Stauch (2016). The new data set (see the Supplementary Materials) comprises 232 OSL ages from sand deposits (Liu et al, 2011, 2012, 2013; Lu et al, 2011, 2015; Stauch et al, 2012, 2016, 2017; Yu and Lai, 2012, 2014; Zhou et al, 2012; Qiang et al, 2013a, 2016; Yu et al, 2013; Lehmkuhl et al, 2014; Hu et al, 2017). The aeolian sand deposits include dunes, sand sheets, and sandy sediments intercalated in loess deposits and fluvial or lacustrine sediments.Figure 2Optically stimulated luminescence (OSL) ages of sand deposits on the northeastern Tibetan Plateau for the last 30 ka.…”
Section: Methodsmentioning
confidence: 99%
“…Aeolian sediments are widespread on the northeastern TP and range from a thin loess cover to fully developed dune systems (e.g., Lehmkuhl, 1997; Lehmkuhl and Haselein, 2000; Sun et al, 2007; Lehmkuhl et al, 2014; Nottebaum et al, 2014; Dong et al, 2017). The main sediment sources are glacial outwash plains (e.g., Sun et al, 2007; Smalley et al, 2014), fluvial deposits, exposed lake beds (Lehmkuhl and Haselein, 2000; Kaiser et al, 2010; IJmker et al, 2012; Yu et al, 2015; Qiang et al, 2016), and older aeolian archives (Stauch et al, 2017). The aeolian system probably is not supply limited because abundant, thick Quaternary valley fill deposits throughout northeastern Tibet can be readily reworked.…”
Different interpretations of accumulation and preservation of aeolian sediments lead to divergent and sometimes contradictory palaeoclimate reconstructions. Although aeolian transport mainly occurs during dry climate, the preservation of the aeolian sediment is a critical factor in many environments in determining the nature of the aeolian sedimentary archive. Analysis of more than 200 optically stimulated luminescence ages for aeolian sands from Tibet shows four different aeolian phases of accumulation. Strong aeolian activity occurred during the last glacial maximum, but hardly any aeolian sediments are preserved. Consequently, the period with the highest aeolian activity is not recorded in the sedimentary record. A phase of aeolian accumulation occurred in the late glacial and the early Holocene. The duration of deposition for this phase is a consequence of the complex topography and an increase in moisture. This phase was punctuated by exceptionally strong accumulation during the Younger Dryas stade. The mid-Holocene is characterised by weak aeolian accumulation and fluvial erosion caused by greater precipitation during the maximum height of the Asian summer monsoon. Aeolian activity resumed in the late Holocene because of drier conditions. The conceptual model provides an approach that can be applied to other mountain and desert margin regions that have limited sediment availability.
“…The semiarid climate conditions and high altitude cause a sparse vegetation cover characterized by alpine steppe around all lakes (Lu et al, ; Miehe et al, ; Müller & Kürschner, ). All catchments are dominated by granitoid to metamorphic bedrock lithology (Akita et al, ; Kasper et al, ; Stauch et al, ), with subordinate occurrences of carbonate outcrops at Lake NC (Kasper et al, ) and HH (Ramisch et al, ). The main differentiation between the lakes is the topographic setting of the surrounding landscapes, which differ in slope gradients (TY > NC > HH) and the average distance for fluvial transport processes (NC > HH > TY) in the drainage basins (Figures b–d).…”
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.
This study investigated a series of dammed lakes and downstream-adjacent alluvial fans in the upstream to middle reaches of the Golmud River in the eastern Kunlun Mountain, on the north-eastern Qinghai-Tibetan Plateau (QTP). An optically stimulated luminescence (OSL) chronology shows the sediments of five dammed lakes developed from c. 45-40, 30-25, 18-14, and 12-8 ka, corresponding to MIS 3b, late MIS 3a, Last Deglaciation, and early Holocene, respectively. The remote sensing data show these dammed lakes have a total area of 109.4 km 2 , with the lake volume of more than 4.0 km 3 . Symmetric alluvial fans from north-south tributary valleys produced OSL ages of c. 61-52, 42-31, 26-20, and 16-10 ka, corresponding to glaciation periods: the MIS 3c and MIS 3a, MIS 2, and the Last Deglaciation. This suggests that glacial activity is responsible for the alluvial fan development, where dammed rivers occurred first, but lake formation did not take place synchronously until later periods of strong hydrologic activity, resulting from northward intrusions of the Indian summer monsoon (ISM) or glacier melt. Thus, the blocking pattern is that river valleys were dammed during periods of glacial activity and lakes formed during wet periods. The lake formation and subsequent drainage may have resulted in:(i) impeded headwater incision and strengthening of downstream dissection;(ii) enriched the halite and potash in the distal Qarhan Salt Lake through hydrologic and hydrochemical processes of abundant water input, the salt lake expansion, salt redissolution from playa and final resedimentation during later dry periods. The alluvial-dammed lake pattern in the mountain-basin systems of eastern Kunlun Mountain offers a model for assessing the linkages between monsoon dynamics, geomorphic processes and distal salt lake evolutions in other arid regions. K E Y W O R D S alluvial-dammed lakes, eastern Kunlun Mountain, OSL dating, paleoclimate changes, salt lake evolution 1 | INTRODUCTION Systematic investigation of the geomorphologic evolution of drainage basins can provide insight into the response of mountain-basin systems to global paleoclimate fluctuations (An, Liu et al., 2018c;Whipple, 2004;Whipple & Tucker, 1999). Reconstructed paleoclimate oscillations from geomorphic processes often focuses on specific sedimentary or geomorphological archives such as fluvial terraces, dammed lake relicts, aeolian sediment sections, and alluvial or glacial landforms. Studies of the coupling relationships between geomorphic dynamics and paleoclimate changes have been carried out worldwide in recent years, for example response of Late Quaternary terrace evolution to climate changes in western Europe and North America
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