A conceptual model for the interpretation of aeolian sediments from a semiarid high-mountain environment since the late glacial

Abstract

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.

Late Quaternary landscape evolution and paleoenvironmental implications from multiple geomorphic dryland systems, Orog Nuur Basin, Mongolia

“…Dry climate conditions are also in accordance with increasing aeolian activity during the late Holocene, which is widely observed in Central Asia (e.g. Peng et al, 2016; Stauch, 2016, 2019; Yang et al, 2017).…”

“…Oldest recovered mountain silt deposits in the Gurvan Bogd date to the mid MIS 2 (Figure 8; ON‐10), however, their deposition is not constrained to that time and also occurred during the Holocene (ON‐136). Mountain silt accumulation in (semi)‐arid mountain ranges is ascribed to sufficiently humid conditions for sustaining a dust‐trapping vegetation cover (Stauch, 2019; Tsoar & Pye, 1987). Thus, considering a sufficient silt supply, their occurrence depends on favourable conditions in the deposition area.…”

14 kyr of atmospheric mineral dust deposition in north-eastern China: A record of palaeoclimatic and palaeoenvironmental changes in the Chinese dust source regions

“…While late-Pleistocene records of aeolian activity other than loess are limited, intensified aeolian activity, based on grain-size fractions, was recorded in lake sediments of arid Central Asia and Lake Qinghai during the YD (An et al, 2011(An et al, , 2012. Enhanced aeolian activity was also inferred from dune records along the southern margin of the Chi-nese desert of northern China during late Pleistocene and the YD (Lu et al, 2013;Stauch, 2019).…”