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Terrestrial Mio-Pliocene Boundary in the linxia basin,Gansu,China

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Acta Geologica Sinica(English Edition) 2011年第2期85卷 452-464页

作者： DENG Tao HOU Sukuan SHI Qinqin CHEN Shaokun HE Wen CHEN Shanqin Key Laboratory of Evolutionary Systematics of Vertebrates Institute of Vertebrate Paleontology and Paleoanthropology the Chinese Academy of Sciences Beijing 100044 China Graduate School of the Chinese Academy of Sciences Beijing 100039 China Hezheng Paleozoological Museum Hezheng Gansu 731200 China

The Lower Pliocene of the linxia basin in Gansu Province is one of only a few representative sections for the Early Pliocene sedimentary records in northern China, and even in East Asia. Recently,abundant mammalian fossils were found from the base of red clays of the Lower Pliocene Hewangjia Formation at Duikang in Guanghe County within this basin. Previously, the Pliocene mammals were sparsely found in China, and most were collected from fluvial and lacustrine deposits in the eastern Loess Plateau. Mammals from the widely distributed Pliocene Hipparion Red Clay are less in number.The known fossils from Duikang include 20 species and belong to the Shilidun Fauna. Their faunal components are similar to the Early Pliocene Gaozhuang Fauna from Ynshe, Shanxi. On the other hand, some taxa from Duikang have not been found in the Gaozhuang Fauna, are slightly more primitive in evolutionary level, and appeared mainly in the Late Miocene. As a result, the age of the Duikang fossils may be slightly earlier than that of the Gaozhuang Fauna and closer to the lower boundary of the Piiocene. The Duikang fossiliferons bed is 0.8 m above the top of the Late Miocene Linshu Formation, and the first occurrence of the three-toed horse Hipparion pater can be regarded as a biostratigraphical marker of the Miocene/Pliocene boundary. In conclusion, Duikang is an ideal candidate locality to establish as the stratotype of the lower boundary of the Chinese terrestrial Pliocene.

关键词： Miocene Pliocene boundary stratotype mammalian fauna Hipparion Red Clay linxia basin

Sequence of the Cenozoic Mammalian Faunas of the linxia basin in Gansu, China

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Acta Geologica Sinica(English Edition) 2004年第1期78卷 8-14页

作者： DENGTao WANGXiaoming NIXijun LIULiping InstituteofVertebratePaleontologyandPaleoanthropology ChineseAcademyofSciencesBeijing100044China NaturalHistoryMuseumofLosAngelesCounty LosAngelesCA90007USA

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.

关键词： linxia basin Cenozoic stratigraphy mammalian fossil Gansu China

Two coldhumid climatic events record in the early Pleistocene deposits of the linxia basin

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西南师范大学学报(自然科学版) 1999年第5期24卷 601-606页

作者： Wang Jianli, Wang Wenjun Schoolof Environment and Resources Science, Southwest China Normal University, Chongqing 400715 西南师范大学重庆

The carbonate contentinthe stratigraphy ofLoessandinlandlakesis a sensitiveindicatorof climatic changes.3 267 samplesintotal were collected at2 5 cm intervalsfrom a 80 m thicklacustrine deposits,spanning 2 35 Myr,in the Dongshanding section of linxia basin.Allthe samples were ana lyzed by using a standard Bascomb calcimeter.The variation of carbonate contents showsthatthere are two obvious cold humid eventsinthe early Pleistocene atabout2 28 Maand 1 8～1 75 Marespective ly.Duringthesetwoperiods,theclimate wascoldorcool.Theclimaticchange wasdominated byan ob vious41 000a periodicity.Theresultsalsoindicatethatinthe early period ofthe Quaternary,the mon soon climate had been established but was notverystable.

关键词： early Pleistocene climatic change linxia basin

Pathological Microstructure of a Miocene Ostrich Eggshell from Asia

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Acta Geologica Sinica(English Edition) 2007年第5期81卷 697-702页

作者： WANG Shuo Department of Biological Science Tianjin Normal University Tianjin 300387

Struthio linxiaensis is the oldest fossil ostrich from Asia till today. This paper analyzes the microstructure of the eggshell of Struthio linxiaensis. The SEM and light microscopic results show that a pathological structure occurred associated with the formation of pore canal. The feature of this structure is that crystals of the columnar layer are around the lower part of the pore canal, and formed a broad structure. This structure unit contracts upwards more severely than the canal and looks like a ＂garlic＂, which was observed in aumiotes eggshells for the first time. Many evidences indicate that this structure was deposited with the columns simultaneously. The radial section view suggests that the ＂garlic structure＂ is not a result of antiperistaltic waves in the avian oviduct. The most possible process of the ＂garlic structure＂ formation is the column units around the pore canals with imperfect acidifying when calcified, or have some correlations with the changes in the protein profiles of the organic matrix in the calcareous eggshell.

关键词： Struthio linxiaensis ostrich egg pathological structure Miocene linxia basin