中国北方黄土地层中的哺乳动物群及在磁性地层中的位置

本文研究了中国黄土地层中有确切层位的哺乳动物化石记录，并进行了生物地层学与磁性地层学对比，将黄土地层中的动物化石归纳成如下哺乳动物群：早更新世（2．50─0．73Ma）：午城动物群（2．50─1．20Ma）、公王岭动物群（1．20─1．10Ma）和阳郭动物群（1．10─0．90Ma）、中更新世（0．73─0．13Ma）：陈家窝子动物群（0．73─0．40Ma）；晚更新世（0．13─0．01Ma）：柔远─靖远动物群（0．13─0．01Ma）；全新世（0．01Ma─Rec）:半坡动物群。结果表明：早更新世许多森林习性的化石动物虽然反映出气候较第三纪的寒冷，但比后期温暖湿润。中更新世出现了较多的草原、干旱草原习性的动物，气候更为寒冷干旱，森林逐渐减少或消失，草原或干旱草原得到发展；晚更新世出现的沙鼠、跳鼠等动物，表明气候更加寒冷、干旱，部分地区甚至沙化。

THE MAMMALIAN FAUNAS IN NORTH CHINESE LOESS AND THE POSITION IN MAGNETOSTRATIGRAPHY

The paper studied the mammalian fossils found in loess layers of north China, andconducted the comparison between biostratigraphy and magnetostratigraphy. Themammalian faunas in Chinese loess were divided as following: Early Pleistocene(2.50 -0.73 Ma): Wucheng mammalian fauna (2.50-1.20Ma), Gongwangling mammalianfauna (1.20-1.10Ma), Yangguo mammalian fauna (1 .10 -0.90Ma); Middle Pleistocene(0.73 -0.13Ma): Chenjiawo mammalian fauna (0.73 -0.40Ma); Late Pleistocene(0.13 -0.01 Ma): Rouyuan-Jingyuan mammalian fauna (0.13 -0.01Ma); Recent(0.01Ma -Rec): Banpo mammalian fauna.The result shows: In Early Pleistocene, there were many fossils of forest animals in theloess layers, which reflect that the climate in the Early Pleistocene was cooler than that inthe Pliocen, but warmer than that of the later stages. Because the climate in the MiddlePleistocene was cooler and drier than that in the late stage, the forest was narrowed downor disappeared gradually. Correspondingly, grassland and drier Steppe were getting expanded.Most of the mammals appeared in the strata were the dwellers of grassland anddrier steppe. In the late Pleistocene, the climate was far cooler and drier, which made evenparts of the areas become sandreld. The fossils of Meriones sp. and Struthilithus sp. werefound in the loess layers of this period.