^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source ...^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source and migration path of key fluids related to development of hydrocarbon, hydrocarbon preservation condition are then discussed further. Comprehensive research, based on the paleo-fluid, the property of formation water and the deformation intensity etc., indicates that the preservation conditions in the Shizhu synclinorium zone and Fangdoushan anticlinorium zone are the most predominant in the central Yangtze. Three sets of fluid systems in the Shizhu synclinorium zone are identified. Little fluid exchange occurs between the upper-middle fluid system and the lower fluid system, so two independent preservation units have developed. Both the Permian and the Triassic in the upper preservation units and the Dengying Formation of the Sinian and the lower Cambrian in the lower preservation units have good preservation conditions. The preservation condition in the lower association （Z-S） located in the Huaguoping synclinorium zone in the western Hubei and Hunan is better than that in other tectonic units, where the fluids in the lower association migrated vertically across strata when the fluid isolating intervals were destroyed, the regional seals are absent and the conditions for the preservation of hydrocarbon accumulations are totally destroyed. The preservation condition is increasingly more favorable from the western Jiangxi and Hunan to the western Hubei ＆ eastern Chongqing on the whole.展开更多
Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this ...Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.展开更多
Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had be...Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had been recognized among accessory minerals. In the present study, attention is focus on the tourmaline bearing quartzite to the southeast of Kombé II. Structure refinement shows that tourmaline is a Fe-dravite with the formula X(Na<sub>0.95</sub>[]<sub>0.05</sub>)Y(Mg<sub>2.39</sub>Fe<sub>0.61</sub>)Z(Al<sub>5.10</sub>Mg<sub>0.90</sub>)(BO<sub>3</sub>)<sub>3</sub>T[Si<sub>6</sub>O<sub>18</sub>](OH)<sub>3</sub>[(O,OH)<sub>0.88</sub>F<sub>0.12</sub>]. The Fe-dravite is hosted in a Ca-poor quartzite, which is made up, in addition to quartz and tourmaline, of biotite and muscovite. The structure of the dravites shows a low vacancy at the X site, which militates for a crystallization of the tourmaline at a high temperature > 750℃. This is in agreement with previous work which shows that the metamorphic peak in the associated biotite gneiss reaches 825℃. The R1 value of 1.24% means that the crystal structure of the tourmalines is of high quality. The genetical link between gold mineralization and tourmaline should stimulate exploration interest in the study area.展开更多
The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone betwe...The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone between the Early Cretaceous granodiorite and the late Permian Xiala Formation limestone.In this study,we achieved detailed zircon U-Pb-Hf isotopes and mineral chemistry for the Early Cretaceous granodiorite.Zircon U-Pb dating results indicate that the Early Cretaceous granodiorite emplaced at ca.119 Ma.Based on the trace elements in zircons and the mineral chemical composition of amphibole and biotite,the Early Cretaceous granodiorite was believed to form under condition of high temperature(>700°C),low pressure(100400 MPa),and relatively high oxygen fugacity(lgfO2)(13.6 to 13.9)and H2O content(4%8%).Zircon trace elements,Hf isotope and biotite chemistry collectively reveal that significant juvenile mantle-derived magmas contributed to the source of the granodiorite.The relatively high logfO2 and shallow magma chamber are beneficial for skarn iron mineralization,implying remarkable potential for further prospecting in the Lunggar iron deposit.展开更多
基金supported by the National Natural Science Foundation(41072082)National Basic Research Program of China(No.2005CB422106)national key subject constructional item of mineralogy,petrology and mineral deposit(SZD0407)and backup candidate fund of academic and technical senior scholar in Sichuan Province
文摘^87Sr/^86Sr, δ^18O and δ^13C ratios of calcite, dolomite, gypsum filling vugs and fissures in marine carbonates and their host rocks from the Sinian to the middle Triassic, are employed to trace the possible source and migration path of key fluids related to development of hydrocarbon, hydrocarbon preservation condition are then discussed further. Comprehensive research, based on the paleo-fluid, the property of formation water and the deformation intensity etc., indicates that the preservation conditions in the Shizhu synclinorium zone and Fangdoushan anticlinorium zone are the most predominant in the central Yangtze. Three sets of fluid systems in the Shizhu synclinorium zone are identified. Little fluid exchange occurs between the upper-middle fluid system and the lower fluid system, so two independent preservation units have developed. Both the Permian and the Triassic in the upper preservation units and the Dengying Formation of the Sinian and the lower Cambrian in the lower preservation units have good preservation conditions. The preservation condition in the lower association （Z-S） located in the Huaguoping synclinorium zone in the western Hubei and Hunan is better than that in other tectonic units, where the fluids in the lower association migrated vertically across strata when the fluid isolating intervals were destroyed, the regional seals are absent and the conditions for the preservation of hydrocarbon accumulations are totally destroyed. The preservation condition is increasingly more favorable from the western Jiangxi and Hunan to the western Hubei ＆ eastern Chongqing on the whole.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road(Pan-TPE)of China(XDA2004030202)Shanghai Cooperation and the Organization Science and Technology Partnership of China(2021E01019)。
文摘Hydrothermal condition is mismatched in arid and semi-arid regions,particularly in Central Asia(including Kazakhstan,Kyrgyzstan,Tajikistan,Uzbekistan,and Turkmenistan),resulting many environmental limitations.In this study,we projected hydrothermal condition in Central Asia based on bias-corrected multi-model ensembles(MMEs)from the Coupled Model Intercomparison Project Phase 6(CMIP6)under four Shared Socioeconomic Pathway and Representative Concentration Pathway(SSP-RCP)scenarios(SSP126(SSP1-RCP2.6),SSP245(SSP2-RCP4.5),SSP460(SSP4-RCP6.0),and SSP585(SSP5-RCP8.5))during 2015-2100.The bias correction and spatial disaggregation,water-thermal product index,and sensitivity analysis were used in this study.The results showed that the hydrothermal condition is mismatched in the central and southern deserts,whereas the region of Pamir Mountains and Tianshan Mountains as well as the northern plains of Kazakhstan showed a matched hydrothermal condition.Compared with the historical period,the matched degree of hydrothermal condition improves during 2046-2075,but degenerates during 2015-2044 and 2076-2100.The change of hydrothermal condition is sensitive to precipitation in the northern regions and the maximum temperatures in the southern regions.The result suggests that the optimal scenario in Central Asia is SSP126 scenario,while SSP585 scenario brings further hydrothermal contradictions.This study provides scientific information for the development and sustainable utilization of hydrothermal resources in arid and semi-arid regions under climate change.
文摘Bafia Group is part of the southernmost portion of the Central African Fold Belt (CAFB) in Cameroon. The geological feature of the group is characterized by the presence of metamorphic rocks in which tourmaline had been recognized among accessory minerals. In the present study, attention is focus on the tourmaline bearing quartzite to the southeast of Kombé II. Structure refinement shows that tourmaline is a Fe-dravite with the formula X(Na<sub>0.95</sub>[]<sub>0.05</sub>)Y(Mg<sub>2.39</sub>Fe<sub>0.61</sub>)Z(Al<sub>5.10</sub>Mg<sub>0.90</sub>)(BO<sub>3</sub>)<sub>3</sub>T[Si<sub>6</sub>O<sub>18</sub>](OH)<sub>3</sub>[(O,OH)<sub>0.88</sub>F<sub>0.12</sub>]. The Fe-dravite is hosted in a Ca-poor quartzite, which is made up, in addition to quartz and tourmaline, of biotite and muscovite. The structure of the dravites shows a low vacancy at the X site, which militates for a crystallization of the tourmaline at a high temperature > 750℃. This is in agreement with previous work which shows that the metamorphic peak in the associated biotite gneiss reaches 825℃. The R1 value of 1.24% means that the crystal structure of the tourmalines is of high quality. The genetical link between gold mineralization and tourmaline should stimulate exploration interest in the study area.
基金Project(2018YSJS14)supported by the Open Research Fund Program of Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,China
文摘The Lunggar iron deposit belongs to the Bangong-Nujiang metallogenic belt and is located in central Lhasa on the Tibetan Plateau.In the Lunggar deposit,iron mineralization formed in the skarnization contact zone between the Early Cretaceous granodiorite and the late Permian Xiala Formation limestone.In this study,we achieved detailed zircon U-Pb-Hf isotopes and mineral chemistry for the Early Cretaceous granodiorite.Zircon U-Pb dating results indicate that the Early Cretaceous granodiorite emplaced at ca.119 Ma.Based on the trace elements in zircons and the mineral chemical composition of amphibole and biotite,the Early Cretaceous granodiorite was believed to form under condition of high temperature(>700°C),low pressure(100400 MPa),and relatively high oxygen fugacity(lgfO2)(13.6 to 13.9)and H2O content(4%8%).Zircon trace elements,Hf isotope and biotite chemistry collectively reveal that significant juvenile mantle-derived magmas contributed to the source of the granodiorite.The relatively high logfO2 and shallow magma chamber are beneficial for skarn iron mineralization,implying remarkable potential for further prospecting in the Lunggar iron deposit.
