Tectonic controls of the onset of aeolian deposits in Chinese Loess Plateau - a preliminary hypothesis

摘要

Previous studies show that the thick aeolian dust deposits in the Chinese Loess Plateau (CLP) have accumulated since the early Miocene or even late Oligocene. They are considered to provide the best terrestrial record for the onset of Asian interior aridification and the evolutionary history of the Asian Monsoon. However, large variability in the basal ages of aeolian deposits makes the aeolian dust depositional history and the controlling dynamics controversial. Here, we present a preliminary hypothesis for the tectonic controls of aeolian dust deposition in the CLP by connecting the two main uplift events of the Tibetan Plateau and the regional tectonic events with the aeolian dust accumulation history. Regional tectonic events in the Ordos Block (the basement of the CLP) during the late Cenozoic are less recognized as controlling aeolian dust accumulation by sculpting the surface landscape. The stable tectonic environment of the Ordos Block since the late Miocene might have been the main controlling factor that enabled the widespread deposition of the aeolian red clay after similar to 8Ma. Here, we hypothesize that because the large-scale monsoon system and central Asian aridity had existed since at least the early Miocene, the accumulation and preservation of aeolian deposits within the CLP are actually largely controlled by the regional tectonic environment and less by climatic factors.