Tarim Precambrian bedrocks are well exposed in the Kuluketage and Aksu areas, where twenty four samples were taken to reveal the denudation history of the northern Tarim Craton. Apatite fission track dating and therma...Tarim Precambrian bedrocks are well exposed in the Kuluketage and Aksu areas, where twenty four samples were taken to reveal the denudation history of the northern Tarim Craton. Apatite fission track dating and thermal history modeling suggest that the northern Tarim experienced multi-stage cooling events which were assumed to be associated with the distant effects of the Cimmerian orogeny and India-Eurasia collision in the past. But the first episode of exhumation in the northern Tarim, occurring in the mid-Permian to Triassic, is here suggested to be induced by docking of the Tarim Craton and final amalgamation of the Central Asian Orogenic Belt. The cooling event at ca. 170 Ma may be triggered by the Qiangtang-Eurasia collision. Widespread Cretaceous exhumation could be linked with docking of the Lhasa terrane in the late Jurassic. Cenozoic reheating and recooling likely occurred because of the northpropagating stress, however, this has not affected the northern Tarim much because the Tarim is characterized by rigid block-like motion.展开更多
To accurately determine the chronological framework of climatic variations recorded by various Martian terrains, the absolute ages of Martian events and cratering rate need to be constrained by either in situ dating o...To accurately determine the chronological framework of climatic variations recorded by various Martian terrains, the absolute ages of Martian events and cratering rate need to be constrained by either in situ dating or returned samples. In situ K-Ar dating is currently a more plausible dating technique as compared with sample return. Jarosite(KFe_(3)[SO_(4)]_(2)[OH]_(6)) is the only confirmed K sulfate mineral that is widely present on Mars, as indicated by in situ detection, orbital remote sensing, and meteorite studies. Jarosite can be used for precise K-Ar and (40)Ar/(39)Ar dating. The preservation of jarosite on Mars provides information about the nature and duration of aqueous processes on the Martian surface. Different ages of Martian jarosite represent the key to constraining the transition from Martian surface water activity to arid climatic conditions. This paper summarizes recent advances in our knowledge of the spatial distribution of Martian jarosite, its mineralogical properties and stability on Mars, the Ar diffusion kinetics of jarosite, and the current status of in situ K-Ar dating. Moreover, we examine the key scientific issues to be addressed for in situ K-Ar dating of jarosite and Martian sample return missions, and discuss future research directions.展开更多
River is one of the geomorphic units that are the most sensitive to tectonic activity, of which the longitudinal profile serves as a key archieve to record information on active tectonics. The stream-power incision mo...River is one of the geomorphic units that are the most sensitive to tectonic activity, of which the longitudinal profile serves as a key archieve to record information on active tectonics. The stream-power incision model is an important means to analyze channel long profiles and to extract both temporal and spatial patterns of regional tectonic activity. Analytical solutions to the steady-state and linear transient-state equations of the model provides means to calibrate drainage basin concavity,calculate channel steepness index, determine drainage divide stability, project the paleo-channel profile, and to invert the tectonic uplift rate history. Yet, not all of these functions have been implemented in the published open-source tools. Here, we developed a set of open-source codes, RiverProAnalysis, which was based on the Matlab platform and integrated all of these functions. The products of the tool set are in the format of image, text and vector files, which not only can be used for visual analysis, but be read by softwares of geographic information system. Taking examples of two transient drainage catchments in the northern margin of the Taiyuan Basin, we analyzed the long profiles of the trunk streams, identified two generations of knickpoints, and estimated the minimum amount of river incision. We combined all the trunk and tributary channels together to model the catchment-wide uplift history and found moderate increases in the uplift rates since the Middle Pliocene and rapid accelation since the late Quaternary. The inverted results are consistent with the sedimentary records in the adjacent basin. By comparing the chi value,slope, and topographic relief of both sides of the catchment divide, we concluded the stability of the drainage divide. Our tool set integrates the main functions of the modern studies on fluvial landsape, thus providing a powerful tool for analyzing river long profiles and for understanding tectonic geomorphology.展开更多
As one of the best established low temperature thermochronology techniques,apatite fission-track(AFT)analysis has proved an important tool for constraining a wide variety of upper crustal processes,e.g.,landscape evol...As one of the best established low temperature thermochronology techniques,apatite fission-track(AFT)analysis has proved an important tool for constraining a wide variety of upper crustal processes,e.g.,landscape evolution,hydrocarbon exploration and tectonics[1].The most common method employed for AFT analysis is the external detector method(EDM)[1]and this involves the thermal neutron irradiation of samples for determination of展开更多
基金financially supported by 973 Program(Grant No. 2014CB440801)NSFC(Grant Nos.41230207 and 41302167)+1 种基金China Postdoctoral Council(Grant Nos.20100480452,2012T50135 and International Postdoctoral Exchange Fellowship)State Key Laboratory of Earthquake Dynamics(Grant No.LED2013B03)
文摘Tarim Precambrian bedrocks are well exposed in the Kuluketage and Aksu areas, where twenty four samples were taken to reveal the denudation history of the northern Tarim Craton. Apatite fission track dating and thermal history modeling suggest that the northern Tarim experienced multi-stage cooling events which were assumed to be associated with the distant effects of the Cimmerian orogeny and India-Eurasia collision in the past. But the first episode of exhumation in the northern Tarim, occurring in the mid-Permian to Triassic, is here suggested to be induced by docking of the Tarim Craton and final amalgamation of the Central Asian Orogenic Belt. The cooling event at ca. 170 Ma may be triggered by the Qiangtang-Eurasia collision. Widespread Cretaceous exhumation could be linked with docking of the Lhasa terrane in the late Jurassic. Cenozoic reheating and recooling likely occurred because of the northpropagating stress, however, this has not affected the northern Tarim much because the Tarim is characterized by rigid block-like motion.
基金supported by the National Natural Science Foundation of China(Grant Nos.42241161,41873063)the Geological Survey Project of China Geological Survey(Grant No.DD20221644)+1 种基金the China Postdoctoral Science Foundation(Grant No.2021M703196)the 2021Graduate Innovation Fund Project of China University of Geosciences,Beijing(Grant No.YB2021YC021)。
文摘To accurately determine the chronological framework of climatic variations recorded by various Martian terrains, the absolute ages of Martian events and cratering rate need to be constrained by either in situ dating or returned samples. In situ K-Ar dating is currently a more plausible dating technique as compared with sample return. Jarosite(KFe_(3)[SO_(4)]_(2)[OH]_(6)) is the only confirmed K sulfate mineral that is widely present on Mars, as indicated by in situ detection, orbital remote sensing, and meteorite studies. Jarosite can be used for precise K-Ar and (40)Ar/(39)Ar dating. The preservation of jarosite on Mars provides information about the nature and duration of aqueous processes on the Martian surface. Different ages of Martian jarosite represent the key to constraining the transition from Martian surface water activity to arid climatic conditions. This paper summarizes recent advances in our knowledge of the spatial distribution of Martian jarosite, its mineralogical properties and stability on Mars, the Ar diffusion kinetics of jarosite, and the current status of in situ K-Ar dating. Moreover, we examine the key scientific issues to be addressed for in situ K-Ar dating of jarosite and Martian sample return missions, and discuss future research directions.
基金supported by the National Natural Science Foundation of China (Grant No. 41802227)。
文摘River is one of the geomorphic units that are the most sensitive to tectonic activity, of which the longitudinal profile serves as a key archieve to record information on active tectonics. The stream-power incision model is an important means to analyze channel long profiles and to extract both temporal and spatial patterns of regional tectonic activity. Analytical solutions to the steady-state and linear transient-state equations of the model provides means to calibrate drainage basin concavity,calculate channel steepness index, determine drainage divide stability, project the paleo-channel profile, and to invert the tectonic uplift rate history. Yet, not all of these functions have been implemented in the published open-source tools. Here, we developed a set of open-source codes, RiverProAnalysis, which was based on the Matlab platform and integrated all of these functions. The products of the tool set are in the format of image, text and vector files, which not only can be used for visual analysis, but be read by softwares of geographic information system. Taking examples of two transient drainage catchments in the northern margin of the Taiyuan Basin, we analyzed the long profiles of the trunk streams, identified two generations of knickpoints, and estimated the minimum amount of river incision. We combined all the trunk and tributary channels together to model the catchment-wide uplift history and found moderate increases in the uplift rates since the Middle Pliocene and rapid accelation since the late Quaternary. The inverted results are consistent with the sedimentary records in the adjacent basin. By comparing the chi value,slope, and topographic relief of both sides of the catchment divide, we concluded the stability of the drainage divide. Our tool set integrates the main functions of the modern studies on fluvial landsape, thus providing a powerful tool for analyzing river long profiles and for understanding tectonic geomorphology.
基金jointly supported by the Fundamental Scientific Research of the Institute of Geology, China Earthquake Administration (IGCEA1509)the National Natural Science Foundation of China (41603054 and 41474053)China Scholarship Council
文摘As one of the best established low temperature thermochronology techniques,apatite fission-track(AFT)analysis has proved an important tool for constraining a wide variety of upper crustal processes,e.g.,landscape evolution,hydrocarbon exploration and tectonics[1].The most common method employed for AFT analysis is the external detector method(EDM)[1]and this involves the thermal neutron irradiation of samples for determination of
