LOESS STRATIGRAPHY OF CENTRAL-ASIA - PALEOCLIMATIC AND PALEOENVIRONMENTAL ASPECTS

The loess-palaeosol succession of Central Asia is comparable with that of the Loess Plateau in North China. Palaeomagnetic investigations an d palaeontological studies in South Tadjikistan suggest a date o 2-25 Ma for the oldest loess, indicating that dust storms became frequent i n the region since 2-2.5 Ma BP. Under the prevalently arid and semi-ar id environments of Central Asia aeolian processes had a gradually incr easing influence on subaerial sedimentation during the Pleistocene. Ho wever, atmospheric aeolian processes in Central Asia have mainly devel oped in accordance with Pleistocene climatic cyclicity, without extrem ely high intensification during the late Pleistocene as implied by the previous TL dating results. The identification of loess and palaeosol horizons with respective glaciations and interglacials is sometimes d isputable. Nevertheless the available data in spite of limited evidenc e, characterise well-developed palaeosols of the middle and late Pleis tocene, as warm and wet intervals associated with interglacials. Palyn ological studies of loess sections show that loess and palaeosol horiz ons have palynological spectra that are sometimes difficult to interpr et. Interregional loess-palaeosol correlation with glacial-interglacia l events as well as with oxygen isotope records should be supplied by multidisciplinary investigations.