The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tung...The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tunggurian Age in 1999. The name of this stage comes from a lithostratigraphic unit, the Tunggur Formation, and the stratotype section is located at the Tunggur tableland, 15 km southeast of Saihan Gobi Township, Sonid Left Banner, Inner Mongolia. The Tunggurian Age is correlated to the Astaracian of the European land mammal ages, and they share the same definition of the lower boundary at the base of the paleomagnetic Chron C5Bn.1r with an age of 15.0 Ma. In the Tairum Nor section on the southeastern edge of the Tunggur tableland, this boundary is situated within the successive deposits of reddish-brown massive mudstone of the lower part of the Tunggur Formation, with a distance of 7.6 m from the base of the grayish-white sandstones in the middle part of the section. The Tunggurian is approximately correlated to the upper part of the marine Langhian and the marine Serravallian in the International Stratigraphical Chart. The Tunggurian Stage includes two Neogene mammal faunal units, i.e. NMU 6 （MN 6） and NMU 7 （MN 7/8）. The Tairnm Nor fauna from the Talrnm Nor section corresponds to NMU 6, and the Tunggur fauna （senso stricto） from the localities on the northwestern edge of the Tunggur tableland, such as Platybelodon Quarry, Wolf Camp and Moergen, corresponds to NMU 7. Among the Middle Miocene mammalian faunas in China, the Laogou fauna from the Linxia Basin, Gansu, the Quantougou fauna from the Lanzhou Basin, Gansu, the Halamagai fauna from the northern Junggar Basin, Xinjiang, and the Dingjiaergou fauna from Tongxin, Ningxia correspond to NMU 6.展开更多
The Qiangtang Basin,located in the Tibetan Plateau,is an appropriate area to verify the Lhasa-Qiangtang collision,which was recorded by the middle-upper part of the Yanshiping Group(the Xiali and Suowa Fms)in the basi...The Qiangtang Basin,located in the Tibetan Plateau,is an appropriate area to verify the Lhasa-Qiangtang collision,which was recorded by the middle-upper part of the Yanshiping Group(the Xiali and Suowa Fms)in the basin.However,the chronology of the Xiali and Suowa Fms is HYPERLINK"javascript:;"controversial,which limits comprehending the timing of the Lhasa-Qiangtang collision.More importantly,HYPERLINK"javascript:;"oil HYPERLINK"javascript:;"shale and salt springs were exposed in the Xiali and Suowa Fms in the basin.544 paleomagnetic samples were collected from the Yanshiping section in the basin in order to reveal the timing of the Lhasa-Qiangtang collision from the view of paleomagnetic ages of the two formations.However,we did not give credible magnetostratigraphic ages of the two formations because of ammonite fossils,a global primary standard for the Jurassic strata correlation,without being found in the last study.Yin(2016)revised the longterm HYPERLINK"javascript:;"controversial paleontological age of the Suowa Fm.from a Tithonian age of the Late Jurassic or a Berriasian age of the Early Cretaceous,to a Middle Bathonian-Middle Callovian age of the Middle Jurassic based on new ammonite fossils.Considering ammonite fossils as a powerful tool and a global primary standard for the Jurassic strata correlation,we attempted to correlate the last magnetostratigraphy with the GPTS 2012 again.Magnetostratigraphic ages of 164.0-160.2 Ma and 160.2-156.8 Ma for the Xiali and Suowa Fms are suggested,respectively.The timing of the Lhasa-Qiangtang collision(156.8-154.9 Ma)is revealed from the magnetostratigraphic ages and the zircon U-Pb age of the Xueshan Fm,154.9(+6.8/−1.6)Ma,overlying the Suowa Fm in the Yanshiping section.展开更多
基金This work is supported by the Knowledge Innovation Program of the Chinese Academy of Sciences （KZCX2- YW-120）the National Commission on Stratigraphy of China+1 种基金the Ministry of Science and Technology of China （2006FY120300, 2006CB806400）the National Natural Science Foundation of China （40232023）.
文摘The Tunggurian Age was nominated in 1984, and the Second National Commission on Stratigraphy of China formally suggested establishing the corresponding chronostratigraphic unit, the Tunggurian Stage, based on the Tunggurian Age in 1999. The name of this stage comes from a lithostratigraphic unit, the Tunggur Formation, and the stratotype section is located at the Tunggur tableland, 15 km southeast of Saihan Gobi Township, Sonid Left Banner, Inner Mongolia. The Tunggurian Age is correlated to the Astaracian of the European land mammal ages, and they share the same definition of the lower boundary at the base of the paleomagnetic Chron C5Bn.1r with an age of 15.0 Ma. In the Tairum Nor section on the southeastern edge of the Tunggur tableland, this boundary is situated within the successive deposits of reddish-brown massive mudstone of the lower part of the Tunggur Formation, with a distance of 7.6 m from the base of the grayish-white sandstones in the middle part of the section. The Tunggurian is approximately correlated to the upper part of the marine Langhian and the marine Serravallian in the International Stratigraphical Chart. The Tunggurian Stage includes two Neogene mammal faunal units, i.e. NMU 6 （MN 6） and NMU 7 （MN 7/8）. The Tairnm Nor fauna from the Talrnm Nor section corresponds to NMU 6, and the Tunggur fauna （senso stricto） from the localities on the northwestern edge of the Tunggur tableland, such as Platybelodon Quarry, Wolf Camp and Moergen, corresponds to NMU 7. Among the Middle Miocene mammalian faunas in China, the Laogou fauna from the Linxia Basin, Gansu, the Quantougou fauna from the Lanzhou Basin, Gansu, the Halamagai fauna from the northern Junggar Basin, Xinjiang, and the Dingjiaergou fauna from Tongxin, Ningxia correspond to NMU 6.
基金supported by National 973 Basic Research Program of China(No.2011CB403003).
文摘The Qiangtang Basin,located in the Tibetan Plateau,is an appropriate area to verify the Lhasa-Qiangtang collision,which was recorded by the middle-upper part of the Yanshiping Group(the Xiali and Suowa Fms)in the basin.However,the chronology of the Xiali and Suowa Fms is HYPERLINK"javascript:;"controversial,which limits comprehending the timing of the Lhasa-Qiangtang collision.More importantly,HYPERLINK"javascript:;"oil HYPERLINK"javascript:;"shale and salt springs were exposed in the Xiali and Suowa Fms in the basin.544 paleomagnetic samples were collected from the Yanshiping section in the basin in order to reveal the timing of the Lhasa-Qiangtang collision from the view of paleomagnetic ages of the two formations.However,we did not give credible magnetostratigraphic ages of the two formations because of ammonite fossils,a global primary standard for the Jurassic strata correlation,without being found in the last study.Yin(2016)revised the longterm HYPERLINK"javascript:;"controversial paleontological age of the Suowa Fm.from a Tithonian age of the Late Jurassic or a Berriasian age of the Early Cretaceous,to a Middle Bathonian-Middle Callovian age of the Middle Jurassic based on new ammonite fossils.Considering ammonite fossils as a powerful tool and a global primary standard for the Jurassic strata correlation,we attempted to correlate the last magnetostratigraphy with the GPTS 2012 again.Magnetostratigraphic ages of 164.0-160.2 Ma and 160.2-156.8 Ma for the Xiali and Suowa Fms are suggested,respectively.The timing of the Lhasa-Qiangtang collision(156.8-154.9 Ma)is revealed from the magnetostratigraphic ages and the zircon U-Pb age of the Xueshan Fm,154.9(+6.8/−1.6)Ma,overlying the Suowa Fm in the Yanshiping section.
