内蒙古淖尔套地区第三系的划分与对比

STRATIGRAPHICAL DIVISION AND CORRELATION OF THE TERTIARY IN THE NAO’ERTAO AREA,INNER MONGOLIA

本文根据内蒙古阿拉善左旗淖尔套地区发现的乌尔图、乌兰塔塔尔和克克阿木三个动物群,厘定了上中新统呼和好来组,命名了下中新统乌尔图组和中渐新统乌兰塔塔尔组,还依岩性对比建立了下渐新统于咀陶组。

The Urtu fauna, Ulantatal fauna and Keke'amu fauna were discovered indifferent Tertiary horizons in the Nao'ertao area, Alxa Left Banner, Inner Mongo-lia. Based on the stratigraphical and paleontological data, a new scheme of stra-tigraphical division of the Tertiary has been proposed, in which the upper Mio-cene Huhehaolai Formation is redefined and the lower Miocene Urtu Formation,middle Oligocene Ulantatal Formation and lower Oligocene Yuzuitao Formation areestablished. Gomphotherium sp. and Megacricetodon sp. in the Urtu fauna that holddefinite horizons are the oldest and most primitive forms in Eurasia, and thelatter might be the earliest form on the earth. The Keke'amu fauna is the earli-est one of the middle Oligocene known so far in Asia.