Abrupt shifts in the late Cenozoic environment of north-western China recorded in loess-palaeosol-red clay sequences

Abstract

Aeolian deposits can provide a sensitive record of climatic change. Two abrupt changes in grain size and accumulation rate have been identified at c. 2.4-2.6 Ma and 1.1-1.2 Ma in the loess-palaeosol-red clay sequences from the Loess Plateau of China. These changes are apparent in two major stepwise increases in grain size and accumulation rate following two abrupt prominent change events of grain size, implying a two-step reorganization that was probably connected with two abrupt environmental change events. The correlation among different sections suggests that regional rather than local environmental processes are responsible for these changes. These changes likely record abrupt fluctuations in winter monsoon and the provenance of sediments associated with renewed Plio-Pleistocene uplift of the Tibetan plateau, and its role on climate and detrital sediment yield.