Based on field investigation in 1999, two deformational domains with d ifferent dynamics have been distinguished from the Jurassic geological outcrops in the Mohe area of NE China, i.e. northern ductile and southern p...Based on field investigation in 1999, two deformational domains with d ifferent dynamics have been distinguished from the Jurassic geological outcrops in the Mohe area of NE China, i.e. northern ductile and southern plastic-brittl e ones. Their deformational features are stated in this paper. And then, three st ages of structural deformation of the area relative to the late Mesozoic orogeni c processes of Mongolian-Okhotsk orogen are reconstructed as follows, (1) south w ards thrusting in the middle-late Jurassic, (2) eastwards thrusting and strike -s lipping parallel to the orogen in the late Jurassic, and (3) southeastwards thru sting in the early Cretaceous.展开更多
The authors took the ETM+ multi-spectra data as the data information and correlation coefficient for each band and carried out their information volume statistics.According to certain criteria,the authors also determi...The authors took the ETM+ multi-spectra data as the data information and correlation coefficient for each band and carried out their information volume statistics.According to certain criteria,the authors also determined the optimum band-combined image.The image clarity is improved by various enhancements and fusions method.Based on remote sensing geological interpretation in detail,the relationship between remote sensing geological characters and gold mine were analyzed systemically.Using all kinds of remote sensing structure information,combining other research data,the authors determined mainly ore-controlling ore structure.Several prospective areas of gold ores were determined and furthermore significant finding mine target areas was confirmed.展开更多
The Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic ...The Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic matter in the Middle Jurassic dark mudstones. This work conducted gas chromatography and isotope mass spectrometry analyses of nearly 90 core gas samples from the Mk-2 well in the Mohe Basin. The results show that the dryness coefficient(C1/C1–5) of core hydrocarbon gas from approximately 900 m intervals below the surface is larger than 98%, over 70% of the δ13 C values of methane are smaller than-55‰, and almost all δD values of methane are smaller than-250‰, indicative of a microbial origin of the gas from almost 900 m of the upper intervals in the Mohe permafrost. Moreover, the biomarker analyses of 72 mudstone samples from the Mohe area indicate that all of them contain 25-norhopane series compounds, thereby suggesting widely distributed microbial activities in the permafrost. This work has confirmed the prevailing existence of microbial gas in the Mohe area, which may be a potential gas source of gas hydrate formation in the Mohe permafrost. This result is of great significance to gas hydrate accumulation in the permafrost across China.展开更多
The Mohe-Upper Amur Basin is situated adjacent to the southern margin of the eastern Mongol-Okhotsk Suture,and its Jurassic-Cretaceous sedimentary infill is crucial for revealing the final closure timing of the Mongol...The Mohe-Upper Amur Basin is situated adjacent to the southern margin of the eastern Mongol-Okhotsk Suture,and its Jurassic-Cretaceous sedimentary infill is crucial for revealing the final closure timing of the Mongol-Okhotsk Ocean and the tectonic evolution of Northeast Asia during the Late Mesozoic.However,there are still ongoing debates regarding the stratigraphic division and provenance evolution of this basin.Based on an analysis of the basin's sedimentary successions and up-todate geochronological data,this study reestablishes a stratigraphic correlation framework between the Mohe part in China and the Upper Amur part in Russia of the basin.The Xiufeng-Mohe formations in the Mohe Basin and the Usmanka-Tolbuzino formations in the Upper Amur Basin represent coeval heteropic successions deposited during the late Middle-early Late Jurassic,while the Kaikukang Formation in the Mohe Basin and Peremykino Formation in the Upper Amur Basin are contemporaneous synonymous stratigraphic units formed during the earliest Early Cretaceous.Detrital zircon U-Pb age spectra reveal that during the Jurassic,prior to the deposition of the Kaikukang Formation,the Mohe-Upper Amur Basin was fed by a single provenance,with sediments derived from the regions to the south of the basin.However,in the earliest Early Cretaceous,during the deposition of the Kaikukang Formation,the tectonic framework of the basin underwent a significant transformation,with a rapid shrinkage in sedimentary extent and the formation of a north-south dual provenance system.Integrating regional tectonic evolutionary data,this study proposes that the compressional tectonic regime and provenance shift recorded in the Mohe-Upper Amur Basin during the late Late Jurassic-earliest Early Cretaceous likely reflect the final closure of the Mongol-Okhotsk Ocean.The two phases of rifting during the late Middle-early Late Jurassic and during the Early Cretaceous may have been controlled by the far-field tectonic effects of a continent-continent collision along the southern margin of the Asian continent,which triggered tectonic escape of Northeast China and dominated the tectonic evolution in Northeast Asia during the Late Mesozoic.展开更多
Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tec...Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the oro- genic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional ac- cumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.展开更多
By using a high-precision LaCoste-Romberg (D-122#) gravimeter, continuous and precise measurements were carried out during the March 9,1997 total solar eclipse in the Mohe region in Northeast China. The gravity variat...By using a high-precision LaCoste-Romberg (D-122#) gravimeter, continuous and precise measurements were carried out during the March 9,1997 total solar eclipse in the Mohe region in Northeast China. The gravity variations were digitally recorded during the total solar eclipse so as to investigate the possible anomaly of the sun and the moon’s gravitational fields on the earth. After the careful processing and analysis of the observed data, no significant anomaly during the very solar eclipse has been found. However, there are two ’gravity anomaly valleys’ with near symmetrical decrease of about 6-7 μGal at the first contact and the last contact. This is the anomaly phenomenon observed and reported for the first time in the literature. This note presents some analyses and discussions.展开更多
文摘Based on field investigation in 1999, two deformational domains with d ifferent dynamics have been distinguished from the Jurassic geological outcrops in the Mohe area of NE China, i.e. northern ductile and southern plastic-brittl e ones. Their deformational features are stated in this paper. And then, three st ages of structural deformation of the area relative to the late Mesozoic orogeni c processes of Mongolian-Okhotsk orogen are reconstructed as follows, (1) south w ards thrusting in the middle-late Jurassic, (2) eastwards thrusting and strike -s lipping parallel to the orogen in the late Jurassic, and (3) southeastwards thru sting in the early Cretaceous.
基金Supported by Project of Land and Resources Department of Heilongjiang Province
文摘The authors took the ETM+ multi-spectra data as the data information and correlation coefficient for each band and carried out their information volume statistics.According to certain criteria,the authors also determined the optimum band-combined image.The image clarity is improved by various enhancements and fusions method.Based on remote sensing geological interpretation in detail,the relationship between remote sensing geological characters and gold mine were analyzed systemically.Using all kinds of remote sensing structure information,combining other research data,the authors determined mainly ore-controlling ore structure.Several prospective areas of gold ores were determined and furthermore significant finding mine target areas was confirmed.
基金supported by Prospecting and Testing Production Project of Gas Hydrate resources, Ministry of Land and Resources of China (grants No. GZHL20110317, GZHL20110320, GZHL20110322)
文摘The Mohe permafrost in northeast China possesses favorable subsurface ambient temperature, salinity, Eh values and pH levels of groundwater for the formation of microbial gas, and the Mohe Basin contains rich organic matter in the Middle Jurassic dark mudstones. This work conducted gas chromatography and isotope mass spectrometry analyses of nearly 90 core gas samples from the Mk-2 well in the Mohe Basin. The results show that the dryness coefficient(C1/C1–5) of core hydrocarbon gas from approximately 900 m intervals below the surface is larger than 98%, over 70% of the δ13 C values of methane are smaller than-55‰, and almost all δD values of methane are smaller than-250‰, indicative of a microbial origin of the gas from almost 900 m of the upper intervals in the Mohe permafrost. Moreover, the biomarker analyses of 72 mudstone samples from the Mohe area indicate that all of them contain 25-norhopane series compounds, thereby suggesting widely distributed microbial activities in the permafrost. This work has confirmed the prevailing existence of microbial gas in the Mohe area, which may be a potential gas source of gas hydrate formation in the Mohe permafrost. This result is of great significance to gas hydrate accumulation in the permafrost across China.
基金supported by the National Natural Science Foundation of China(Grant No.42402116)the Natural Science Foundation of Hunan Province of China(Grant No.2022JJ40370)。
文摘The Mohe-Upper Amur Basin is situated adjacent to the southern margin of the eastern Mongol-Okhotsk Suture,and its Jurassic-Cretaceous sedimentary infill is crucial for revealing the final closure timing of the Mongol-Okhotsk Ocean and the tectonic evolution of Northeast Asia during the Late Mesozoic.However,there are still ongoing debates regarding the stratigraphic division and provenance evolution of this basin.Based on an analysis of the basin's sedimentary successions and up-todate geochronological data,this study reestablishes a stratigraphic correlation framework between the Mohe part in China and the Upper Amur part in Russia of the basin.The Xiufeng-Mohe formations in the Mohe Basin and the Usmanka-Tolbuzino formations in the Upper Amur Basin represent coeval heteropic successions deposited during the late Middle-early Late Jurassic,while the Kaikukang Formation in the Mohe Basin and Peremykino Formation in the Upper Amur Basin are contemporaneous synonymous stratigraphic units formed during the earliest Early Cretaceous.Detrital zircon U-Pb age spectra reveal that during the Jurassic,prior to the deposition of the Kaikukang Formation,the Mohe-Upper Amur Basin was fed by a single provenance,with sediments derived from the regions to the south of the basin.However,in the earliest Early Cretaceous,during the deposition of the Kaikukang Formation,the tectonic framework of the basin underwent a significant transformation,with a rapid shrinkage in sedimentary extent and the formation of a north-south dual provenance system.Integrating regional tectonic evolutionary data,this study proposes that the compressional tectonic regime and provenance shift recorded in the Mohe-Upper Amur Basin during the late Late Jurassic-earliest Early Cretaceous likely reflect the final closure of the Mongol-Okhotsk Ocean.The two phases of rifting during the late Middle-early Late Jurassic and during the Early Cretaceous may have been controlled by the far-field tectonic effects of a continent-continent collision along the southern margin of the Asian continent,which triggered tectonic escape of Northeast China and dominated the tectonic evolution in Northeast Asia during the Late Mesozoic.
基金supported by the National Natu-ral Science Foundation of China(Grant Nos.49872 066 and 40132020).
文摘Discrimination of sandstone geochemistry to tectonic settings and provenance has become an effective method in the studies of complex geological circumstances because of its higher sensitivity for the stability of tectonic settings in the period of basin deposition. Results of geochemical analyses in this paper show that sandstone samples of the Mesozoic Mohe basin fall in active continental margin settings on several kinds of tectonic discriminatory diagrams (Bhatia et al. 1983, 1986; Roser et al. 1986,1988,1999). The samples are also characterized by binary-system provenances, whose terrigenous clastic materials mainly derived from the oro- genic belt near the basin to the north and secondarily from the continental region in the south of the basin at the same time. The research results of rock geochemistry, combined with tectonic analysis, reflect that tectonic type of the basin is a foreland basin with nature of depositional ac- cumulation of molass, but not continental rift basin considered in the past. This finding provides important evidence of rock geochemistry for the original structural linkage between the Mohe Foreland Basin and Mongol-Okhotsk Orogen in Mesozoic.
基金This work was supported by the Commission of Science and Technology of China and the Chinese Academy of Sciences, and the National Natural Science Foundation of China.
文摘By using a high-precision LaCoste-Romberg (D-122#) gravimeter, continuous and precise measurements were carried out during the March 9,1997 total solar eclipse in the Mohe region in Northeast China. The gravity variations were digitally recorded during the total solar eclipse so as to investigate the possible anomaly of the sun and the moon’s gravitational fields on the earth. After the careful processing and analysis of the observed data, no significant anomaly during the very solar eclipse has been found. However, there are two ’gravity anomaly valleys’ with near symmetrical decrease of about 6-7 μGal at the first contact and the last contact. This is the anomaly phenomenon observed and reported for the first time in the literature. This note presents some analyses and discussions.
