Three exceptionally strong East-Asian summer monsoon events during glacial times in the past 470 kyr

摘要: Abstract. Chinese loess sequences are interpreted as a reliable record of the past variation East Asian monsoon regime through alternation and paleosols units, dominated by winter summer monsoon, respectively. Different proxies have been used to describe this system, mostly geophysical, geochemical or sedimentological. Terrestrial mollusks also proxy environmental conditions often preserved in large numbers deposits. The analysis mollusk remains Luochuan sequence, comprising L5 S0 soil, i.e. last 500 ka, shows that for almost all identified species, abundance is higher at base interval (L5 L4) than younger Using present ecological requirements species sequence allows definition two main groups varying during kyr. cold-aridiphilous individuals indicate so-called predominantly occur glacials, when dust deposited. thermal-humidiphilous prevalent interglacial interstadial soil formation takes place. In three events with exceptionally high indicators recorded L5, L4 L2 glacial intervals, i.e., about 470, 360 170 kyr, appear be strongest (high counts). Similar variations Xifeng distant enough from Luochuan, but Lake Baikal further North, suggest phenomenon regional rather local. within intervals imply strengthened East-Asian corresponding marine isotope stages 12, 10 6, monsoons coeval Mediterranean sapropels S12 S6, which characterize strong African relatively low surface water salinity Indian Ocean. Changes precipitation could correspond response particular astronomical configuration (low obliquity, precession, solstice perihelion) leading an increased insolation gradient between tropics latitudes resulting enhanced atmospheric transport continents. However, other climate drivers such reorganization circulations, tectonic, extent Northern Hemisphere ice sheet discussed.