ELEMENTS DISTRIBUTION OF THE DENGJIA LOESS SECTION, CENTRAL HENAN AND ITS ENVIRONMENTAL IMPLICATIONS

A loess-paleosol sedtion formed since the last deglaciation was discovered at Dengjia,Xinzheng county,Henan Province.The distributions of Mg、Fe、K、Mn、Ba、Sr and CaCO₃、SiO₂ are studied in details. Results show that the evolution of loess deposits was closely related with climate changes.During the last deglaciation,there were two humid periods in 16 kaBP and 9 kaBP,and two arid periods in 12 kaBP and 2 kaBP respectively in this region.The Ca/Mg ratio is an effective climate proxy,which has close relation with grain size.It is revealed that the leaching of loess was stronger in early HMP(Holocene Megathermal Period)rather than in later HMP.Central Henan has suffered environmental changes from cool-dry, cool-humid,cool-dry,warm-humid to warm-dry since the last deglaciation.