A Marked Climatic Change and Mammal Migration during Early Pleistocene Time in North China

摘要

In 1985, Cao and others discovered a new vertebrate site of Early Pleistocene age, called East Cave at Zhoukoudian. Since then, the authors have collected numerous mammal fossils from Iayer8 and Iayer7 of the East Cave section, and found ice wedge casts in Iayer7 and Iayer6. Crocidura sp., Lepus sp., Hypolagus cf. brachypus, Alilepus zhoukoudianensis, Sciurotamias praecox, Spermophihis sp., AUocricetus ehiki, A, '? teilhardi, A. sp., Cricetinus varians, Cricetulus barabensis, Hyperacrius yenshanensis, Allicola sp., allophaiomys cf. pliocaenicus, Proedromys cf. bedfordi, Lasiopodomys prohrandii, Apodemus dominans, A. ? latromim, A. cf. penmsulae. Niviventer precofucianus, Mus cf. mscuhis, Micromys sp., Chardinotnys nihewamcus, Canis sp.and Meles sp. are recognized in this collection. Dominant arid steppe and cryophilous elements of the Palaeoarctic Region in the assemblage, and the ice wedge casts in the fossiliferous layers, show a drop in temperature and an animal migration event southwards in North China. This cooling event took place about 1.20 Ma., and the temperature is estimated 12-17'C lower than that at present.