中国黄土中的仓鼠、鼢鼠化石及在磁性地层中的位置

The Cricetinae and Siphneidae Fossils in Chinese Loess and Their Location in Magnetostratigraph

研究了中国黄土中的仓鼠、鼢鼠化石，及其在磁性地层中的位置，并将其按时间分布划分为４个阶段：中间原鼢鼠Ｍｅｓｏｓｌｐｈｎｅｕｓｔｉｎｔｅｒｍｅｄｔｕｓ阶段（３．４０～２．４５Ｍａ）、奥米加鼢鼠Ｙｏｕｎｇｉａｏｍｅｇｏｄｏｎ阶段（２．４５～１．６０Ｍａ）、丁氏鼢鼠Ｙ．ｔｉｎｇｉ阶段（２．００～０．７３Ｍａ）、方氏鼢鼠Ｅｏｓｐａｌａｘｆｏｎｔｏｎｉｅｒｉ－沙鼠Ｍｅｒｉｏｎｅｓ阶段（０．７３Ｍａ～Ｒｅｃ．）。第一阶段处于新生代以来最后的温暖湿热时期；第二阶段代表了湿热气候环境的最终结束、干冷气候的开始；第三阶段反映了相对干冷的气候环境，以及干冷－湿热气候的频繁波动；第四阶段气候更加寒冷干旱，部分黄土地区沙化。

The Cricetinae and Siphneidae fossils in Chinese loess are studied,and their seats in Megnetostratigraph are determined.They are dividied into four stages: Mesosiphneus intermedius stage (3.40～2.45 Ma),Youngia omegodon stage(2.45～1.60 Ma),Y.tingi stage (2.00～0.73 Ma),and Eospalax fonianteri-meriones stage(0.73 Ma～Rec).The 1st stage is located at the last warm and moist epoch of Cenozoic.It shows in the 2nd stage the climate of warm-moist was end,and got cool and dry.The 3rd climate epoch was cool-dry,and frequently fluetuating between cool-dry and warmmoist.In the 4 th stage,the climate became cooler and drier,which made even parts of the loess areas became sandfield.