The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil resources.Equids are abundant in the Linxia Basin,the fossil record of equids in this region including 16 ...The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil resources.Equids are abundant in the Linxia Basin,the fossil record of equids in this region including 16 species that represent 10 genera.In comparison to other classic late Cenozoic areas in China,the Linxia Basin stands out,because the fauna and chronological data accompanying Linxia equids render them remarkably useful for biostratigraphy.The anchitheriines in the region,such as Anchitherium and Sinohippus,represent early equids that appeared in the late stages of the middle and late Miocene,respectively.Among the equines,most species of Chinese hipparions have been identified in the Linxia Basin and some species of the genera Hipparion and Hippotherium have FAD records for China.Furthermore,Equus eisenmannae is one of the earliest known species of Equus in the Old World and is well-represented at the Longdan locality.Some species with precise geohistorical distributions can serve as standards for high-resolution chronological units within this framework.Located at the eastern margin of the Tibetan Plateau and subject to considerable uplift,the Linxia Basin has served as a biogeographic transition area for equids throughout the late Cenozoic.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
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 fo...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.展开更多
Linxia Basin is a late Cenozoic fault-block basin along the border between the Tibet plateau and the Loess plateau in Northwestern China. Its formation and sediments record may be directly affected by the structural d...Linxia Basin is a late Cenozoic fault-block basin along the border between the Tibet plateau and the Loess plateau in Northwestern China. Its formation and sediments record may be directly affected by the structural dynamics and the uplift of the Tibet Plateau. For this reason, we studied the mineral characteristics of the Maogou formation of Miocene sediments using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that quartz, chlorite, illite, calcite, plagioclase, orthoclase, kaolinite, and trace palygorskite are present throughout the sequence of the cross-section in Linxia basin. In contrast, gypsum and ankerite occur occasionally in the upper portion of the Miocene deposits. The content of calcite varied with layers in the profile and was relatively concentrated in mudstone. Chlorite and illite were observed transforming into palygorskite under SEM observation. Based on the mineral characteristics and the change of mineral composition, especially the clay minerals, it could be inferred that an arid environment prevailed in the region with warm and cold intervals during Miocene time.展开更多
基金supported by National Key Research and Development Program of China(Grant No.2023YFF0804501)the Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2021069)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB31000000)the Second Comprehensive Scientific Expedition on the Tibetan Plateau(Grant No.2019QZKK0705)the All China Commission of Stratigraphy(Grant No.DD20221829).
文摘The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil resources.Equids are abundant in the Linxia Basin,the fossil record of equids in this region including 16 species that represent 10 genera.In comparison to other classic late Cenozoic areas in China,the Linxia Basin stands out,because the fauna and chronological data accompanying Linxia equids render them remarkably useful for biostratigraphy.The anchitheriines in the region,such as Anchitherium and Sinohippus,represent early equids that appeared in the late stages of the middle and late Miocene,respectively.Among the equines,most species of Chinese hipparions have been identified in the Linxia Basin and some species of the genera Hipparion and Hippotherium have FAD records for China.Furthermore,Equus eisenmannae is one of the earliest known species of Equus in the Old World and is well-represented at the Longdan locality.Some species with precise geohistorical distributions can serve as standards for high-resolution chronological units within this framework.Located at the eastern margin of the Tibetan Plateau and subject to considerable uplift,the Linxia Basin has served as a biogeographic transition area for equids throughout the late Cenozoic.
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.
基金supported by the Ministry of Science and Technology of China (2006FY120300 and 2006CB806400)the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-120, Q09)the National Natural Science Foundation of China (40730210), and the All-China Stratigraphic Commission
文摘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.
文摘Linxia Basin is a late Cenozoic fault-block basin along the border between the Tibet plateau and the Loess plateau in Northwestern China. Its formation and sediments record may be directly affected by the structural dynamics and the uplift of the Tibet Plateau. For this reason, we studied the mineral characteristics of the Maogou formation of Miocene sediments using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that quartz, chlorite, illite, calcite, plagioclase, orthoclase, kaolinite, and trace palygorskite are present throughout the sequence of the cross-section in Linxia basin. In contrast, gypsum and ankerite occur occasionally in the upper portion of the Miocene deposits. The content of calcite varied with layers in the profile and was relatively concentrated in mudstone. Chlorite and illite were observed transforming into palygorskite under SEM observation. Based on the mineral characteristics and the change of mineral composition, especially the clay minerals, it could be inferred that an arid environment prevailed in the region with warm and cold intervals during Miocene time.
基金supported by the National Key Research and Development Program of China(No.2023YFF0804501)the National Natural Science Foundation of China(Grant No.42102001)+1 种基金the R+D+I project PID2020-116220GB-I00 funded by the Agencia Estatal de Investigación of the Spanish Ministry of Science and Innovation(MCIN/AEI/10.13039/501100011033/)the Research Group UCM 910607.
