The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented,based on rock magnetic experiments and magnetostratigraphic investiga-tions of a 192 m th...The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented,based on rock magnetic experiments and magnetostratigraphic investiga-tions of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization,and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS). Furthermore,the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary,and the Suosuoquan fauna layer is just above the Neocene onset. Therefore,the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma,respectively.展开更多
In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early P...In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence.展开更多
基金Supported by the National Natural Science Foundation of China (Grant Nos. 40372202 and 40172610)National Important Basic Research Project of China (Grant No. G2003CB214607)
文摘The first detailed chronology for the late Oligocene to early Miocene continental record in northern Junggar Basin is presented,based on rock magnetic experiments and magnetostratigraphic investiga-tions of a 192 m thick mammal-bearing section in the Ulungur River area. Magnetites and hematites were identified as the main carriers for the characteristic remanent magnetization,and the resulting polarity sequence allows an unambiguous correlation to the geomagnetic polarity time scale (GPTS). Furthermore,the Tieersihabahe fauna layer occurs below the Paleocene/Neocene boundary,and the Suosuoquan fauna layer is just above the Neocene onset. Therefore,the age of the Tieersihabahe fauna and Suosuoquan fauna layers can be definitely estimated to be about 25.2 Ma and 22.5 Ma,respectively.
基金the National Natural Science Foundation of China(No.40232023)Chinese Academy of Sciences(No.KZCX2-103,RJZ2001-105)Ministry of Science and Technology of China(No.G2000077700).
文摘In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence.
