陇西黄土高原马兰黄土划分与末次冰期气候快速变化研究

High Resolution Record of Malan Loess in the Longxi Loess Plateau and Rapid Climate Changes during the Last Glaciation

陇西黄土高原马兰黄土内存在９个弱成壤组（层），记录了末次冰欺内多达２２个间冰段气候的环境状况。马兰黄土中部古土壤是末次冰期大间冰段的记录，共有上、中、下３层古土壤，含１１个亚层，尤以下层古土壤发育最好，表明当时气候较温暖湿润。陇西马兰黄土记录与格陵兰ＧＲＩＰ冰芯记录相吻合。

Loess is Widely distributed in the Longxi Loess Plateau. Loess deposiition in the plateau is quite sensiitive to enviironmental and/or climatic changes. Because it is relative thick in the Plateau the loess climatic record has high resolution. Malan loess is 30 m to 50 m thick in the plateau. Yuandao section in Linxia basin and Gaolanshan section in Lanzhou are two typicalMalan loess sections in the plateau with more than 30 m thick Malan loess. It is found that there are 22 weak pedogeniic layers in it. They are the record of interstades in the last glaciation. From pedogenic structures, magnetic susceptibility index, pollen and spore composition and others it is known that climates in the interstades were relative warm and moist. The Mallan loess record is quite coincited with Greenland GRIP ice core record, reflecting the general instable climate for whole global during the last glaciation. In middle part of Malan loess thare are a thick interstadial pedogenic layer with three main paleosols. The climate in that period was quite moist, and possible as warm as presen tin some time especially in the bottom paleosol formation. In wewtern China, Water Level of Inland Lakes was higher than that of Presents. The interstade in China appeared as a Mega_interstade.