TERTIARY OF THE ALXA AREA, INNER MONGOLIA, CHINA

摘要

Tertiary of Alxa area is mainly composed of inland fluviolacustrine deposits. Litnostratigraphically it can be divided into 7 formations: Middle Eocene Wulanwuzhur Formation, Upper Eocene Chaganbulage Formation, Lower Oligocene Ulantatal Formation, Upper Oligocene-Lower Miocene Urtu Formation, Upper Miocene Huhehaolai Formatians and Pliocene Angganghaote Formation. The abundant Tertiary fossils, especially mammal fossils, can be classified into 8 faunas or assemblages: Middle Eocene Wulanwuzhur fauna, Late Eocene Chaganbulage fauna, early Early Oligocene Kekeamu fauna, late Early Oligocene Ulantatal fauna, Late Oligocene assemblage, Early Miocene Urtu fauna, Late Miocene Huhehaolai assemblage, and Pliocene Angganghaote assemblage.