Paleoclimatic implications from late Quaternary terrestrial archives in the Gobi Desert: examples from the Ejina Basin and Orog Nuur Basin [thesis]

Kaifeng Yu, Frank Lehmkuhl, Bernhard Diekmann
Considerable efforts have been devoted to disentangle the late Quaternary moisture and thermal evolution of arid central Asia. However, an array of paramount aspects has inhibited our complete understanding of the broad pattern of Quaternary moisture and thermal history of arid central Asia and underlying mechanisms.The Ejina Basin, with its suite of different sediment archives, is known as one of the main sources for the loess accumulation on the Chinese Loess Plateau. In order to understand
more » ... chanisms along this supra-regional sediment cascade (aeolian, fluvial and alluvial sediments), it is crucial to decipher the archive characteristics and formation processes. Five sediment archives from three lithologic units exhibit geochemical characteristics as follows: (i) aeolian sands have high contents of Zirconium and Hafnium, whereas only Hafnium can be regarded as a valuable indicator to discriminate the coarse sand proportion; (ii) sandy loess has high Calcium and Strontium contents which both exhibit broad correlations with the medium to coarse silt proportions; (iii) lacustrine clays have high contents of felsic, ferromagnesian and mica source elements e.g., Potassium, Iron, Titanium, Vanadium, and Nickel; (iv) fluvial sands have high contents of Magnesium, Chlorine and Sodium which may be enriched in evaporite minerals; (v) alluvial gravels have high contents of Chromium which may originate from nearby Cr-rich bedrock. Temporal variations can be illustrated by four robust factors: weathering intensity, silicate-bearing mineral abundance, saline / alkaline magnitude and quasi-constant aeolian input. In summary, the bulk-composition of the late Quaternary sediments in this arid context is governed by the nature of the source terrain, weak chemical weathering, authigenic minerals, aeolian sand input, whereas pedogenesis and diagenesis exert only limited influences. Hence, here demonstrates a practical geochemical strategy to discriminate sediment archives and thereafter enhance our ability to offer more intriguin [...]
doi:10.18154/rwth-2017-01045 fatcat:kgdxa672uzdbpkcqldzzp3bzmq