The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the record...The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the records of Cenozoic sedimentary sequence and detrital provenance in these basins are often obscure,making the interpretation of the drainage reorganization quite difficult.This research discovered the earliest Late Cenozoic fluvial conglomerate in the Yuanmou Basin,one of the fault basins in SE Tibet,and named the conglomerate as'the Yuanmou Gravel Layer(YMG)'.Clast petrography,morphology and paleocurrent directions of the YMG indicate that the conglomerate is the remain of a large paleo river traversing through the Yuanmou Basin from north to south.Detrital zircon U-Pb ages can imply the YMG has similar provenance areas with Anning,Dadu and Yalong rivers at age peaks of 175-275,600-1000,and 2100-2700 Ma,but the lack of the age peak of 30-100 Ma from Qiangtang Block implies that the paleo-river was not yet connected with the Jinsha River during the YMG's accumulation.The fluvial-lacustrine strata with gravel beds containing paleosimian fossils comparable to the YMG were deposited~7-11 Ma,further suggesting that the pre-formed south-flowing river was active during the Late Miocene.展开更多
Englacial and subglacial drainage systems of temperate glaciers have a strong influence on glacier dynamics, glacier-induced floods, glacier-weathering processes, and runoff from glacierized drainage basins. Proglacia...Englacial and subglacial drainage systems of temperate glaciers have a strong influence on glacier dynamics, glacier-induced floods, glacier-weathering processes, and runoff from glacierized drainage basins. Proglacial discharge is partly controlled by the geometry of the glacial drainage network and by the process of producing meltwater. The glacial-drainage system of some alpine glaciers has been characterized using a model based on proglacial discharge analysis. In this paper, we apply cross-correlation analysis to hourly hydro-climatic data collected from China＇s Hailuogou Glacier, a typical temperate glacier in Mt. Gongga, to study the seasonal status changes of the englacial and subglacial drainage systems by discharge-temperature （Q-T） time lag analy-sis. During early ablation season （April-May） of 2003, 2004 and 2005, the change of englacial and subglacial drainage system usually leads several outburst flood events, which are also substantiated by observing the leakage of supraglacial pond and cre-vasses pond water during field works in April, 2008. At the end of ablation season （October-December）, the glacial-drainage net-works become less hydro-efficient. Those events are evidenced by hourly hydro-process near the terminus of Hailuogou Glacier, and the analysis of Q-T time lags also can be a good indicator of those changes. However, more detailed observations or experi-ments, e.g. dye-tracing experiment and recording borehole water level variations, are necessary to describe the evolutionary status and processes of englacial and subglacial drainage systems evolution during ablation season.展开更多
Lop Sea,located at the east end of the Tarim Basin,Northwest China,dried up permanently,which is the terminal lake of the Tarim River.Lop Sea was considered as the lake basin of Lop Nor since Quaternary.However,the po...Lop Sea,located at the east end of the Tarim Basin,Northwest China,dried up permanently,which is the terminal lake of the Tarim River.Lop Sea was considered as the lake basin of Lop Nor since Quaternary.However,the possibility that Lop Nor was away from the Lop Sea in historical time is crucial to be discussed to interpret the proxy records in sediment profiles.To obtain a general view of the evolution of Lop Nor and Lop Sea in a historical period,several approaches were adopted in this paper.First,the Qianlong Thirteen-Row Atlas,an ancient imperial atlas of the Qing Dynasty,which was completed around 1760,indicated that the Tarim River formed a relatively large lake at its modern upstream region.Second,a Digital Elevation Model(DEM)with a 10-m spatial resolution and a relative precision of 0.42 m was derived from TanDEM-X/Terra SAR-X satellite image pairs using the interferometry method,which was verified using ICESat-GLAS laser footprints and a local DEM acquired by a drone.Finally,based on the spatial analysis of historical documents,expedition reports,sediment profiles and archaeological evidence,it can be deduced that the lacustrine deposition was discontinued in the Lop Sea.Six episodes in the evolutionary history of the drainage system in eastern Tarim Basin were summarized.The proved depositional condition variations could be used for future interpretation of proxy records in sediment.The high-accurate DEM provided a reference for the location of further fieldwork in the Lop Sea.The method proposed in this paper may be efficient for the research of inland lakes or rivers in global arid regions.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.41671011,41672355,41871019)the State Key Laboratory of Continental Dynamic,Northwest University,Xi'an,China。
文摘The active deforming southeastern margin of the Tibetan Plateau has developed series of fault basins filled with fluvial-lacustrine sediment deposited by drainage systems during every stage of its uplifting,the records of Cenozoic sedimentary sequence and detrital provenance in these basins are often obscure,making the interpretation of the drainage reorganization quite difficult.This research discovered the earliest Late Cenozoic fluvial conglomerate in the Yuanmou Basin,one of the fault basins in SE Tibet,and named the conglomerate as'the Yuanmou Gravel Layer(YMG)'.Clast petrography,morphology and paleocurrent directions of the YMG indicate that the conglomerate is the remain of a large paleo river traversing through the Yuanmou Basin from north to south.Detrital zircon U-Pb ages can imply the YMG has similar provenance areas with Anning,Dadu and Yalong rivers at age peaks of 175-275,600-1000,and 2100-2700 Ma,but the lack of the age peak of 30-100 Ma from Qiangtang Block implies that the paleo-river was not yet connected with the Jinsha River during the YMG's accumulation.The fluvial-lacustrine strata with gravel beds containing paleosimian fossils comparable to the YMG were deposited~7-11 Ma,further suggesting that the pre-formed south-flowing river was active during the Late Miocene.
基金supported by the National Natural Science Foundation of China (Grant No. 40801030 and 40801025)the Major State Basic Research Development Program of China (973 Program) (2007CB411506)+1 种基金the Innovation Project of Chinese Academy Sciences (Kzcx2-yw-301)the National Basic Work Program of Chinese MST (Glacier Inventory of China Ⅱ, Grant No. 2006FY110200)
文摘Englacial and subglacial drainage systems of temperate glaciers have a strong influence on glacier dynamics, glacier-induced floods, glacier-weathering processes, and runoff from glacierized drainage basins. Proglacial discharge is partly controlled by the geometry of the glacial drainage network and by the process of producing meltwater. The glacial-drainage system of some alpine glaciers has been characterized using a model based on proglacial discharge analysis. In this paper, we apply cross-correlation analysis to hourly hydro-climatic data collected from China＇s Hailuogou Glacier, a typical temperate glacier in Mt. Gongga, to study the seasonal status changes of the englacial and subglacial drainage systems by discharge-temperature （Q-T） time lag analy-sis. During early ablation season （April-May） of 2003, 2004 and 2005, the change of englacial and subglacial drainage system usually leads several outburst flood events, which are also substantiated by observing the leakage of supraglacial pond and cre-vasses pond water during field works in April, 2008. At the end of ablation season （October-December）, the glacial-drainage net-works become less hydro-efficient. Those events are evidenced by hourly hydro-process near the terminus of Hailuogou Glacier, and the analysis of Q-T time lags also can be a good indicator of those changes. However, more detailed observations or experi-ments, e.g. dye-tracing experiment and recording borehole water level variations, are necessary to describe the evolutionary status and processes of englacial and subglacial drainage systems evolution during ablation season.
基金supported by the National Natural Science Foundation of China(42071313,41671353,U1303285,41571363,41431174,61471358,41201346,41301394,41301464)。
文摘Lop Sea,located at the east end of the Tarim Basin,Northwest China,dried up permanently,which is the terminal lake of the Tarim River.Lop Sea was considered as the lake basin of Lop Nor since Quaternary.However,the possibility that Lop Nor was away from the Lop Sea in historical time is crucial to be discussed to interpret the proxy records in sediment profiles.To obtain a general view of the evolution of Lop Nor and Lop Sea in a historical period,several approaches were adopted in this paper.First,the Qianlong Thirteen-Row Atlas,an ancient imperial atlas of the Qing Dynasty,which was completed around 1760,indicated that the Tarim River formed a relatively large lake at its modern upstream region.Second,a Digital Elevation Model(DEM)with a 10-m spatial resolution and a relative precision of 0.42 m was derived from TanDEM-X/Terra SAR-X satellite image pairs using the interferometry method,which was verified using ICESat-GLAS laser footprints and a local DEM acquired by a drone.Finally,based on the spatial analysis of historical documents,expedition reports,sediment profiles and archaeological evidence,it can be deduced that the lacustrine deposition was discontinued in the Lop Sea.Six episodes in the evolutionary history of the drainage system in eastern Tarim Basin were summarized.The proved depositional condition variations could be used for future interpretation of proxy records in sediment.The high-accurate DEM provided a reference for the location of further fieldwork in the Lop Sea.The method proposed in this paper may be efficient for the research of inland lakes or rivers in global arid regions.
