Jm. Sun et al., 580,000-year environmental reconstruction from aeolian deposits at the Mu Us Desert margin, China, QUAT SCI R, 18(12), 1999, pp. 1351-1364
A 76.7 Pn-thick section of aeolian sediment is exposed in the transition zo
ne between the Mu Us Desert and the Loess Plateau of northern China. The ae
olian sediments contain sand beds, loess layers, and palaeosols. The partic
le-size distribution data and the SEM examination of quartz grains suggest
the sand beds are wind-blown origin. Palaeomagnetic measuring combined with
thermoluminescence (TL) dating and pedostratigraphic correlation suggests
the studied aeolian sequences were deposited within about 580 kyr. The sand
layers appear to reflect the episodic extensions of Mu Us Desert during ph
ases of active dune formation and intensified winter monsoon. Both the stra
tigraphy and the proxy climatic curves such as bulk magnetic susceptibility
and grain size indicate that large amplitude second-order climatic oscilla
tions occur during both glacial and interglacial periods. It is worth notin
g that nearly all the interglacial soils can be sub-divided by the intercal
ated sand or loess beds, this second-order climatic oscillations are on the
order of 10,000 of years which may reflect the precession-scale variations
of southeast summer monsoon driven by the orbital pacing of insolation in
low latitudes. (C) 1999 Elsevier Science Ltd. All rights reserved.