The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deform...The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deformation and uplift histories of the northern Tibetan Plateau. The Kunlun-Yellow River Movement, identified from the tectonomorphologic and sedimentary evolution of the Kunlun Pass Basin by Cui Zhijiu et al. (1997, 1998), is roughly coincident with many important global and Plateau climatic and environmental events, becoming a crucial time interval to understand tectonic-climatic interactions. However, the ages used to constrict the events remain great uncertainty. Here, we present the results of detailed magnetostratigraphy of the late Cenozoic sediments in the Kunlun Pass Basin, which show the basin sediments were formed between about 3.6 Ma and 0.5 Ma and the Kunlun-Yellow River Movement occurred at 1.2 to ～0.78 Ma. The lithology, sedimentary facies and lithofacies associations divide the basin into five stages of tectonosedimentary evolution, indicating the northern Tibetan Plateau having experienced five episodes of tectonic uplifts at ～3.6, 2.69－2.58, 1.77, 1.2, 0.87 and ～0.78 Ma since the Pliocene.展开更多
Here described are the cyprinid fossils from the Pliocene Lower Member of Qiangtang Formation of the Kunlun Pass Basin,northeastern Tibetan Plateau,collected at a locality 4769 m above the sea level(asl).The materials...Here described are the cyprinid fossils from the Pliocene Lower Member of Qiangtang Formation of the Kunlun Pass Basin,northeastern Tibetan Plateau,collected at a locality 4769 m above the sea level(asl).The materials consist of numerous disarticulated and incomplete bones as well as thousands of pharyngeal teeth,fin rays,and vertebrae.The fossils were referred to the genus Gymnocypris,lineage Schizothoracini,family Cyprinidae;the lineage Schizothoracini;and the family Cyprinidae respectively.The Schizothoracini is a freshwater fish group endemic to the Tibetan Plateau and its surrounding area.Previous workers on living schizothoracins regarded that Gymnocypris belongs to the highly specialized grade of the group,colonizing higher altitudes than other members of the group.Two species are so far unequivocally assigned to the genus,i.e.,G.przewalskii and G.eckloni,and they are inhabiting Qinghai Lake and the waters on both north(the Golmud River) and south(upper reach of the Yellow River) sides of the East Kunlun Mountain,respectively.The abundant fossil schizothoracins occur in the Kunlun Pass Basin on the southern slope of the East Kunlun Mountain(at 4769 m asl),close to the present Golmud River,indicating comparatively rich waters in the area and possible connections between the water systems on north and south sides of the East Kunlun Mountain during the Pliocene.This also suggests a more humid climate in the area during the Pliocene than it is today.The presence of the highly specialized schizothoracin Gymnocypris may also imply less amplitude of uplift(approximately 1000 m) in the area since the Pliocene than previously proposed.展开更多
Here described are the nemacheilid fossils from the Pliocene Lower Member of Qiangtang Formation in the Kunlun Pass Basin,northeastern Tibetan Plateau,at a locality 4769 m above the sea level (a.s.l.).The materials co...Here described are the nemacheilid fossils from the Pliocene Lower Member of Qiangtang Formation in the Kunlun Pass Basin,northeastern Tibetan Plateau,at a locality 4769 m above the sea level (a.s.l.).The materials consist of numerous disarticulated and incomplete bones.The fish remains are assigned to the Nemacheilidae based on the fused compound centrum of the 2nd and 3rd vertebrae with developed bifurcate lateral processes of the 2nd vertebra.The fossils also include the maxilla,the dentary,the anguloarticular,the quadrate,the hyomandibular,the opercle,the basihyal,the urohyal,the anterior ceratohyal,the posterior ceratohyal,the interhyal and the supracleithrum.These bones are very similar to their counterparts in some species of a Recent nemacheilid genus,Triplophysa (Nemacheilidae,Cypriniformes),which is widely distributed on the Tibetan Plateau.The nemacheilid fossils are much more abundant than the remains of schizothoracines embedded in the same horizon at the same locality.This would imply that the number of individuals of Triplophysa was much higher than that of schizothoracines when they were alive in the area.In Recent ichthyofauna of the Tibetan Plateau,Triplophysa prevails over schizothoracines in the number of individuals in the high elevations and small water bodies.Based on the fossil dominance of Triplophysa over schizothoracines and their taphonomical conditions,it appears that the water system at the Kunlun Pass area during the Pliocene might not be extensive lakes or large rivers with broad valleys.There might have been a few mountainous,relatively torrential rivers with many small,shallow streams connecting the water systems from the north and south of the East Kunlun Mountain.The environment of the Kunlun Pass Basin area during the Pliocene must be very harsh,and the altitude of the area might already have been higher than we previously suggested.The uplift of the area must be less than 1000 m since the Pliocene.展开更多
基金This work was supported by the National Natu-ral Science Foundation of China(Grand Nos.40421101,40121303,40334038).
文摘The Kunlun Pass Basin, located in the middle of the eastern Kunlun Mountains, received relatively continuous late Cenozoic sediments from the surrounding mountains, archiving great information to understand the deformation and uplift histories of the northern Tibetan Plateau. The Kunlun-Yellow River Movement, identified from the tectonomorphologic and sedimentary evolution of the Kunlun Pass Basin by Cui Zhijiu et al. (1997, 1998), is roughly coincident with many important global and Plateau climatic and environmental events, becoming a crucial time interval to understand tectonic-climatic interactions. However, the ages used to constrict the events remain great uncertainty. Here, we present the results of detailed magnetostratigraphy of the late Cenozoic sediments in the Kunlun Pass Basin, which show the basin sediments were formed between about 3.6 Ma and 0.5 Ma and the Kunlun-Yellow River Movement occurred at 1.2 to ～0.78 Ma. The lithology, sedimentary facies and lithofacies associations divide the basin into five stages of tectonosedimentary evolution, indicating the northern Tibetan Plateau having experienced five episodes of tectonic uplifts at ～3.6, 2.69－2.58, 1.77, 1.2, 0.87 and ～0.78 Ma since the Pliocene.
基金supported by the National Natural Science Foundation of China (Grant Nos.40432003,40802010)Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No.KZCX2-YW-Q09)+1 种基金CToL Project under the U.S.National Science Foundation to R.Mayden (Grant No.EF0431326)the Ecocarp Project (European Commission,INCO-DEV Programme,Grant No.ICA4-CT-2001-10024)
文摘Here described are the cyprinid fossils from the Pliocene Lower Member of Qiangtang Formation of the Kunlun Pass Basin,northeastern Tibetan Plateau,collected at a locality 4769 m above the sea level(asl).The materials consist of numerous disarticulated and incomplete bones as well as thousands of pharyngeal teeth,fin rays,and vertebrae.The fossils were referred to the genus Gymnocypris,lineage Schizothoracini,family Cyprinidae;the lineage Schizothoracini;and the family Cyprinidae respectively.The Schizothoracini is a freshwater fish group endemic to the Tibetan Plateau and its surrounding area.Previous workers on living schizothoracins regarded that Gymnocypris belongs to the highly specialized grade of the group,colonizing higher altitudes than other members of the group.Two species are so far unequivocally assigned to the genus,i.e.,G.przewalskii and G.eckloni,and they are inhabiting Qinghai Lake and the waters on both north(the Golmud River) and south(upper reach of the Yellow River) sides of the East Kunlun Mountain,respectively.The abundant fossil schizothoracins occur in the Kunlun Pass Basin on the southern slope of the East Kunlun Mountain(at 4769 m asl),close to the present Golmud River,indicating comparatively rich waters in the area and possible connections between the water systems on north and south sides of the East Kunlun Mountain during the Pliocene.This also suggests a more humid climate in the area during the Pliocene than it is today.The presence of the highly specialized schizothoracin Gymnocypris may also imply less amplitude of uplift(approximately 1000 m) in the area since the Pliocene than previously proposed.
基金supported by the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No. KZCX2-YW-Q09)National Basic Research Program of China (Grant No. 2012CB821900)+1 种基金National Natural Science Foundation of China (Grant No. 40802010)Key Laboratory of Evolu-tionary Systematics of Vertebrates,IVPP,CAS (Grant No. 2011LESV005)
文摘Here described are the nemacheilid fossils from the Pliocene Lower Member of Qiangtang Formation in the Kunlun Pass Basin,northeastern Tibetan Plateau,at a locality 4769 m above the sea level (a.s.l.).The materials consist of numerous disarticulated and incomplete bones.The fish remains are assigned to the Nemacheilidae based on the fused compound centrum of the 2nd and 3rd vertebrae with developed bifurcate lateral processes of the 2nd vertebra.The fossils also include the maxilla,the dentary,the anguloarticular,the quadrate,the hyomandibular,the opercle,the basihyal,the urohyal,the anterior ceratohyal,the posterior ceratohyal,the interhyal and the supracleithrum.These bones are very similar to their counterparts in some species of a Recent nemacheilid genus,Triplophysa (Nemacheilidae,Cypriniformes),which is widely distributed on the Tibetan Plateau.The nemacheilid fossils are much more abundant than the remains of schizothoracines embedded in the same horizon at the same locality.This would imply that the number of individuals of Triplophysa was much higher than that of schizothoracines when they were alive in the area.In Recent ichthyofauna of the Tibetan Plateau,Triplophysa prevails over schizothoracines in the number of individuals in the high elevations and small water bodies.Based on the fossil dominance of Triplophysa over schizothoracines and their taphonomical conditions,it appears that the water system at the Kunlun Pass area during the Pliocene might not be extensive lakes or large rivers with broad valleys.There might have been a few mountainous,relatively torrential rivers with many small,shallow streams connecting the water systems from the north and south of the East Kunlun Mountain.The environment of the Kunlun Pass Basin area during the Pliocene must be very harsh,and the altitude of the area might already have been higher than we previously suggested.The uplift of the area must be less than 1000 m since the Pliocene.
