"主日"走进耶路撒冷stepping in Jerusalem on the Lord’s day从复活节的前一个主日起,到复活节的这一个礼拜,被称为"受难周",或者"圣周",受难周的第一天,便是棕树主日。也就在这一日,我们一行人来到这..."主日"走进耶路撒冷stepping in Jerusalem on the Lord’s day从复活节的前一个主日起,到复活节的这一个礼拜,被称为"受难周",或者"圣周",受难周的第一天,便是棕树主日。也就在这一日,我们一行人来到这座世界上最美、最悲伤的城市——耶路撒冷(Jerusalem)。耶路撒冷老城是犹太教、基督教和伊斯兰教的圣地,是世界上唯一享有此殊荣的城市。耶路撒冷神奇的传说、浓郁的宗教色彩,丰富的古迹和独特的情调,令人十分神往。展开更多
Orogenic peridotites in the Dabie-Sulu orogenic belt are commonly subdivided into‘crustal’type and‘mantle’type.They exhibit distinct mineral textures,metamorphic evolution,and whole-rock and mineral compositions.M...Orogenic peridotites in the Dabie-Sulu orogenic belt are commonly subdivided into‘crustal’type and‘mantle’type.They exhibit distinct mineral textures,metamorphic evolution,and whole-rock and mineral compositions.Most‘mantle’type peridotites originated from the subcontinental lithospheric mantle(SCLM)of the North China Craton and thus provide direct evidence of crust-mantle interactions in the continental subduction channel.In garnet peridotites,both garnet and Cr-spinel can be equilibrated at peak pressure conditions.Their stabilities are mainly controlled by the refertilized degree of whole-rock;therefore,spinel composition cannot be used to discriminate the partial melting degree of orogenic peridotites.Refractory mantle-derived dunites contain the textures of low Mg and high Ca olivine veins that crosscut orthopyroxene porphyroblasts,which is considered as evidence for silica-undersaturated melt-rock reactions.Such reactions occurring before subduction may potentially affect Re-Os isotopic compositions.Rutile,Ti-clinohumite and zircon in mantle-derived peridotites or pyroxenites provide direct mineralogical evidence for the transport of high field strength elements(HFSEs)from the subducted crust into the mantle wedge.Based on detailed in situ element and isotope analyses,we can constrain the source of metasomatic agents,the metasomatic time and the process of mass transfer.The mantle wedge above continental subduction zones has a wide range of oxygen fugacity values(FMQ=?5.50–1.75),showing a roughly negative correlation with the subducted depths.However,the calculated results of oxygen fugacity are significantly affected by mineral assemblages,P-T conditions and dehydrogenation-oxidation of nominally anhydrous mantle olivine during exhumation.Although significant progress has been made in the study of orogenic peridotites in the Dabie-Sulu orogenic belt,many critical questions remain.With new approaches and advanced technologic applications,additional knowledge of the phase relation in the peridotite-pyroxenite complex system,the mantle geodynamic process before continental subduction,the effects of crustal metasomatism on chemical composition,the oxygen fugacity,and the physical properties of the mantle wedge is anticipated.展开更多
High-Mg （Mg#〉45） andesites （HMA） within cratons attract great attention from geologists. Their origin remains strongly debated. In order to examine and provide direct evidence for previous assumptions about HMA＇...High-Mg （Mg#〉45） andesites （HMA） within cratons attract great attention from geologists. Their origin remains strongly debated. In order to examine and provide direct evidence for previous assumptions about HMA＇s genesis inferred from petrolog- ical and geochemical investigations, we performed reaction experiments between tonalitic melt and mantle olivine on a six-anvil apparatus at high-temperature of 1250-1400℃ and high-pressure of 2.0-5.0 GPa. Our experiments in this work simulated the interaction between the tonalitic melt derived from partial melting of eclogitized lower crust foundering into the Earth＇s mantle and mantle peridotite. The experimental results show that the reacted melts have very similar variations in chemical compositions to the HMAs within the North China Craton. Therefore, this interaction is probably an important pro- cess to generate the HMAs within crations.展开更多
文摘"主日"走进耶路撒冷stepping in Jerusalem on the Lord’s day从复活节的前一个主日起,到复活节的这一个礼拜,被称为"受难周",或者"圣周",受难周的第一天,便是棕树主日。也就在这一日,我们一行人来到这座世界上最美、最悲伤的城市——耶路撒冷(Jerusalem)。耶路撒冷老城是犹太教、基督教和伊斯兰教的圣地,是世界上唯一享有此殊荣的城市。耶路撒冷神奇的传说、浓郁的宗教色彩,丰富的古迹和独特的情调,令人十分神往。
基金supported by the National Basic Research Program of China(Grant No.2015CB856103)the National Natural Science Foundation of China(Grant Nos.41090371&41372078)
文摘Orogenic peridotites in the Dabie-Sulu orogenic belt are commonly subdivided into‘crustal’type and‘mantle’type.They exhibit distinct mineral textures,metamorphic evolution,and whole-rock and mineral compositions.Most‘mantle’type peridotites originated from the subcontinental lithospheric mantle(SCLM)of the North China Craton and thus provide direct evidence of crust-mantle interactions in the continental subduction channel.In garnet peridotites,both garnet and Cr-spinel can be equilibrated at peak pressure conditions.Their stabilities are mainly controlled by the refertilized degree of whole-rock;therefore,spinel composition cannot be used to discriminate the partial melting degree of orogenic peridotites.Refractory mantle-derived dunites contain the textures of low Mg and high Ca olivine veins that crosscut orthopyroxene porphyroblasts,which is considered as evidence for silica-undersaturated melt-rock reactions.Such reactions occurring before subduction may potentially affect Re-Os isotopic compositions.Rutile,Ti-clinohumite and zircon in mantle-derived peridotites or pyroxenites provide direct mineralogical evidence for the transport of high field strength elements(HFSEs)from the subducted crust into the mantle wedge.Based on detailed in situ element and isotope analyses,we can constrain the source of metasomatic agents,the metasomatic time and the process of mass transfer.The mantle wedge above continental subduction zones has a wide range of oxygen fugacity values(FMQ=?5.50–1.75),showing a roughly negative correlation with the subducted depths.However,the calculated results of oxygen fugacity are significantly affected by mineral assemblages,P-T conditions and dehydrogenation-oxidation of nominally anhydrous mantle olivine during exhumation.Although significant progress has been made in the study of orogenic peridotites in the Dabie-Sulu orogenic belt,many critical questions remain.With new approaches and advanced technologic applications,additional knowledge of the phase relation in the peridotite-pyroxenite complex system,the mantle geodynamic process before continental subduction,the effects of crustal metasomatism on chemical composition,the oxygen fugacity,and the physical properties of the mantle wedge is anticipated.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-YW-Q08-3-4)the project from the State Key Laboratory for Mineral Deposits Research,Nanjing University(Grant No.15-09-08)
文摘High-Mg （Mg#〉45） andesites （HMA） within cratons attract great attention from geologists. Their origin remains strongly debated. In order to examine and provide direct evidence for previous assumptions about HMA＇s genesis inferred from petrolog- ical and geochemical investigations, we performed reaction experiments between tonalitic melt and mantle olivine on a six-anvil apparatus at high-temperature of 1250-1400℃ and high-pressure of 2.0-5.0 GPa. Our experiments in this work simulated the interaction between the tonalitic melt derived from partial melting of eclogitized lower crust foundering into the Earth＇s mantle and mantle peridotite. The experimental results show that the reacted melts have very similar variations in chemical compositions to the HMAs within the North China Craton. Therefore, this interaction is probably an important pro- cess to generate the HMAs within crations.
