This paper presents a biotite-calcic hornblende geothermometer which was empirically calibrated based on the garnet-biotite geothermometer and the garnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 56...This paper presents a biotite-calcic hornblende geothermometer which was empirically calibrated based on the garnet-biotite geothermometer and the garnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560 800°C (T) and 0.26?1.4 Gpa (P) using the data of metadolerite, amphibolite, metagabbro, and metapelite collected from the literature. Biotite was treated as symmetric Fe-Mg-AlVI-Ti quaternary solid solution, and calcic hornblende was simplified as symmetric Fe-Mg binary solid solution. The resulting thermometer may rebuild the input garnet-biotite temperatures well within an uncertainty of 50°C. Errors of 0.2 Gpa for input pressure, along with analytical errors of 5% for the relevant mineral compositions, may lead to a random error of 16°C for this thermometer, so that the thermometer is almost independent of pressure estimates. The thermometer may clearly discriminate different rocks of lower amphibolite, upper amphibolite and granulite facies on a high confidence level. It is assumed that there is a ferric iron content of 11.6% in biotite, and that the iron content in calcic hornblende may be calculated according to the method of Dale et al. (2000). This thermometer can be used for medium- to high-grade metabasites and metapelites.展开更多
Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental man...Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental mantle evolution(partial melting and metasomatism in upper mantle).Until now,varieties of sulfide inclusions have been extensively discovered in the ultramafic or mafic phenocrysts.However,previous展开更多
The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triass...The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triassic cumulate hornblende gabbro was identified in the southern margin of the Gangdese magmatic belt.The gabbro exhibits cumulate structure,with hornblende and plagioclase as the primary mineral phases.Isotopic data indicate a hydrous magma source derived from a depleted mantle wedge that has been modified by slab dehydration.Geochemical discriminations suggest that the gabbro was formed in an intraoceanic arc setting,with crystallization ages of ca.220-213 Ma.Hornblende,hornblendelagioclase and ilmenite thermometers reveal that the crystallization temperature of 900-750°C for the gabbro.Hornblende and hornblende-plagioclase geobarometers yield an emplacement depth at ca.14.5-19.5 km.This gabbro constitutes a line of evidence for an intraoceanic arc magmatism that is coeval with the counterparts in the southern Turkey,revealing an intraoceanic subduction system within the Neotethys from west to east in the Late Triassic and that the oceanization of the Neotethys was much earlier than previous expectation.展开更多
OM (optical microscope)/TEM (transmission electron microscope) micro- and submicrostructural analysis of hornblende rocks sheared at high temperatures from the Diancangshan area, western Yunnan reveals evidence for de...OM (optical microscope)/TEM (transmission electron microscope) micro- and submicrostructural analysis of hornblende rocks sheared at high temperatures from the Diancangshan area, western Yunnan reveals evidence for deformation in the brittle-ductile transition of hornblende at middle crustal level (about 637℃ and 0.653 GPa) and mechanisms of deformation in the transitional regime are further discussed. Sheared hornblende rocks at middle crustal level have typical mylonitic microstructures, shown by coarse porphyroclasts and fine matrix grains. Different mineral phases in the rocks show distinct deformation characteristics. Hornblende and feldspar grains are intensely deformed with ob- vious grainsize reduction, but quartz grains are recrystallized dominantly by grain growth. Hornblende grains show typical brittle-ductile transition nature. Initial crystallographic orientations of porphyro- clasts have strong effects on the behavior of grains during deformation. There are mainly two types of porphyroclasts, type I "hard" porphyroclasts and type II "soft" porphyroclasts, with [001] perpendicular and parallel to external shear stresses respectively. "Hard" porphyroclasts generally occur as compe- tent grains that are rarely deformed or sometimes deformed by fracturing and dislocation tangling. "Soft" porphyroclasts are highly deformed primarily by dislocation tangling (as shown in the cores of the porphyroclasts), but twinning, dislocation glide and climb probably due to hydrolytic weakening also contribute to dynamic recrystallization of the porphyroclasts into fine grains in the matrix. The micro- and submicrostructures of the two types of porphyroclasts and fine-grained matrix provide powerful evidence for the behavior of brittle-ductile transition of hornblende grains. It is concluded that twinning nucleation is one of the most important processes that operate during dynamic recrystalliza- tion of hornblende crystals at the brittle-ductile transition. (100) [001] twin gliding and dislocation creep (dislocation glide and climb) are mutually enhanced during twinning nucleation. As a newly discovered mechanism of dynamic recrystallization, it may have played more important roles than ever recognized during dynamic recrystallization of crystals with twins in the brittle-ductile transition.展开更多
The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrita...The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.展开更多
Rocks of the late Neoproterozoic Askaoun pluton (558 ± 2 Ma) located in the Ouzellarh-Sirwa promontory (Anti-Atlas) include magmatic microgranular enclaves (MMEs) ranging from rounded to ovoid in shape, dark and ...Rocks of the late Neoproterozoic Askaoun pluton (558 ± 2 Ma) located in the Ouzellarh-Sirwa promontory (Anti-Atlas) include magmatic microgranular enclaves (MMEs) ranging from rounded to ovoid in shape, dark and fine grained and generally 5 to 10 cm in size, some reaching a size of 50 cm. They are composed of microdiorite, quartz microdiorite and micromonzodiorite, whereas the felsic host rocks comprise mainly quartz-diorite and amphibole-biotite granodiorite based on mineralogical compositions. The mineral assemblage is similar to those described in their hosting granitoids but with different proportions. In this study composition of minerals is used to describe the nature of the magma and estimate the pressure, temperature and oxygen fugacity at which Askaoun pluton is emplaced. Based on chemistry of biotite Askaoun pluton formed from calc-alkaline magma. Compositions of plagioclase (An5 - An29);hornblende (Mg ≠= 0.59 - 0.65) and biotite (Mg ≠= 0.49 - 0.55) of MMEs are slightly distinct or similar to those of host rocks (An7-40;hbl Mg ≠= 0.64 - 0.69;Bi Mg ≠= 0.49 - 0.50) which suggest partial to complete equilibration during mafic-felsic magma interaction. The coexisting hornblende and plagioclase (hornblende-plagioclase thermometry), Al content in hornblende (aluminum-in-hornblende barometry) and the assemblage titanite-magnetite-quartz were used to constrain the P, T and fO2 during the crystallization of the parent magmas. The Askaoun pluton was emplaced at temperature ca. 504°C - 633°C and at pressure ca. 0.9 - 4.66 ± 0.6 Kbars (average depth = 6.5 km) from a highly oxidized magma (log fO2 = ?24.8 to ?19.2).展开更多
There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inliertype in the northeast-east of Yell,Shetland.This zone with a north—northwesterlytrend consists of blastomylonised hornblende-banded ...There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inliertype in the northeast-east of Yell,Shetland.This zone with a north—northwesterlytrend consists of blastomylonised hornblende-banded gneiss,hornblende-feldspar gneissand mica-felsie-gneiss with lenses of hornblende gneiss.It is indicated that theblastomylonite zone is actually a ductile shear zone and the sense of shear is dextral.This contributes to understanding the details of tectonic evolution in this area,and thiszone is probably a part of tectonic system of the British Caledonides.展开更多
The present work is a petrological study of the gabbroic rocks of wadi Shianite Southeastern Desert of Egypt. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. These are: 1)?pyr...The present work is a petrological study of the gabbroic rocks of wadi Shianite Southeastern Desert of Egypt. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. These are: 1)?pyroxene hornblende gabbronorite;?2) hornblende gabbro;?and 3) anorthosite.?The opaque minerals study of the gabbroic rocks showed that they composed mainly of ilmenite, magnetite and sulphides. The present gabbroic rocks work are related to calc-alkaline magma type, similar to the younger gabbros in other areas in the Eastern Desert.展开更多
The geology of the Zango-Daji area was investigated petrographically and geochemically to determine the study area’s rock types and mineralization potential.The study area is underlain by rocks of the basement comple...The geology of the Zango-Daji area was investigated petrographically and geochemically to determine the study area’s rock types and mineralization potential.The study area is underlain by rocks of the basement complex characterized by hilly and undulating rocks,which include granitic gneiss,migmatite gneiss,biotite hornblende granite gneiss,and pegmatites.Observation from the field shows that the study area is dominantly underlain by granitic gneiss.The granitic gneiss is dark grey,medium-coarse-grained,and characterized by weak foliation defined by the alignment of a streak of light and dark coloured minerals.They are widespread in the area constituting about 70%of rock types found in the study area.The average modal percentage of minerals in the rocks from petrographic studies shows that granitic gneiss had quartz 45%,plagioclase 10%,microcline 20%,hornblende 2%,biotite 10%,muscovite 5%,kyanite 8%and other minerals 5%.Also,the pegmatite of the study area has no evidence of mineralization;it contains minerals like quartz,feldspars(microcline and orthoclase),and micas(mostly muscovite).Geochemical analysis of the granitic gneiss of the study area shows that silica is by far the most abundant with a value of 53.5%,Na_(2)O value of 32.5%,Al_(2)O_(3),and k_(2)O of 6.1%and 4.0%,respectively.CaO value of 2.630%accounts for plagioclase feldspar in the granitic gneiss.The QAP diagram was used to determine the petrogenesis of the granitic gneiss.The plot shows the parent rock was a monzogranite with a low percentage of plagioclase in a thin section with a high percentage of quartz and alkali feldspar.The pegmatites of the study area are barren,as confirmed by the XRD result.展开更多
Isotope dating, hornblende geobarometer, fission-track analysis and fluid inclusion homogeneous temperature analysis have been applied to Caledonian, Variscan and Yenshan plutons in Bei Huaiyang (BHY) and Dabie erogen...Isotope dating, hornblende geobarometer, fission-track analysis and fluid inclusion homogeneous temperature analysis have been applied to Caledonian, Variscan and Yenshan plutons in Bei Huaiyang (BHY) and Dabie erogenic belt (DOB), and the emplaced depths and ages of these plutons have been obtained in order to obtain differential uplift time and uplift heights between BHY and DOB since late Paleozoic era. BHY had experienced three stages of uplift (C1-C2, T-J2, J3-K1) and its total uplift height is about 10 km, but, DOB had only experienced two stages of uplift (T-J2, J3-K1) and its maximum uplift height is more than 15 km. BHY uplift occurred mainly before the mid-Jurassic (about 150 Ma), but DOB uplift took place after the mid-Jurassic (about 150 Ma).展开更多
The Jialuhe basic-intermediate intrusion is situated inside of the Xiangjia'nanshan granitic batholith at the eastern end of the East Kunlun orogenic belt. It is mainly composed of hornblende gabbro and quartz dio...The Jialuhe basic-intermediate intrusion is situated inside of the Xiangjia'nanshan granitic batholith at the eastern end of the East Kunlun orogenic belt. It is mainly composed of hornblende gabbro and quartz diorite. LA —ICP— MS zircon U —Pb dating showed that the Jialuhe intrusion was emplaced at 220 Ma. The rocks have low SiO2 (47. 91%-58. 92%) and Al2O3 (15. 54 %-18. 35%) contents, low A/CNK(0. 70-0. 90) ratios, high Mg^#(46- 61), and display metaluminous middle-K calc - alkaline affinities.展开更多
基金the China National Natural Science Foundation(grants40002017 , 40074022) wasalso under the auspices of the National Key Project for Basic Research +1 种基金 CAS Project for the Tibetan Research Project(KZ.-951-A1-204 , KZ95T-06) a China Geological Survey grant(J2.1.4).
文摘This paper presents a biotite-calcic hornblende geothermometer which was empirically calibrated based on the garnet-biotite geothermometer and the garnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560 800°C (T) and 0.26?1.4 Gpa (P) using the data of metadolerite, amphibolite, metagabbro, and metapelite collected from the literature. Biotite was treated as symmetric Fe-Mg-AlVI-Ti quaternary solid solution, and calcic hornblende was simplified as symmetric Fe-Mg binary solid solution. The resulting thermometer may rebuild the input garnet-biotite temperatures well within an uncertainty of 50°C. Errors of 0.2 Gpa for input pressure, along with analytical errors of 5% for the relevant mineral compositions, may lead to a random error of 16°C for this thermometer, so that the thermometer is almost independent of pressure estimates. The thermometer may clearly discriminate different rocks of lower amphibolite, upper amphibolite and granulite facies on a high confidence level. It is assumed that there is a ferric iron content of 11.6% in biotite, and that the iron content in calcic hornblende may be calculated according to the method of Dale et al. (2000). This thermometer can be used for medium- to high-grade metabasites and metapelites.
基金financially supported by the National Natural Science Foundation of China(grant No. 41302062)the China Geological Survey(grant No. 12120115034401)
文摘Objective Sulfide inclusions within natural mineral phases play important roles in exploring the origin of magmatic sulfides ores,tracing the distribution of sulfur in mantle or crust and understanding continental mantle evolution(partial melting and metasomatism in upper mantle).Until now,varieties of sulfide inclusions have been extensively discovered in the ultramafic or mafic phenocrysts.However,previous
文摘The Neotethys plays an important role in shaping the Gangdese magmatic belt,southern Tibet.However,the initial time of spreading and subduction of the Neotethys remains contentious.In this study,a suite of late Triassic cumulate hornblende gabbro was identified in the southern margin of the Gangdese magmatic belt.The gabbro exhibits cumulate structure,with hornblende and plagioclase as the primary mineral phases.Isotopic data indicate a hydrous magma source derived from a depleted mantle wedge that has been modified by slab dehydration.Geochemical discriminations suggest that the gabbro was formed in an intraoceanic arc setting,with crystallization ages of ca.220-213 Ma.Hornblende,hornblendelagioclase and ilmenite thermometers reveal that the crystallization temperature of 900-750°C for the gabbro.Hornblende and hornblende-plagioclase geobarometers yield an emplacement depth at ca.14.5-19.5 km.This gabbro constitutes a line of evidence for an intraoceanic arc magmatism that is coeval with the counterparts in the southern Turkey,revealing an intraoceanic subduction system within the Neotethys from west to east in the Late Triassic and that the oceanization of the Neotethys was much earlier than previous expectation.
基金State Key Research "973" Plan of China (Grant No. 2002CB412607)Geological Survey of China Project (Grant No. 1212010661311)+1 种基金State Key Laboratory of Geological Processes and Mineral Resources (Grant No. GPMR200637)the Project of Ministry of Science and Technology (Grant No. 2006BAB01A03)
文摘OM (optical microscope)/TEM (transmission electron microscope) micro- and submicrostructural analysis of hornblende rocks sheared at high temperatures from the Diancangshan area, western Yunnan reveals evidence for deformation in the brittle-ductile transition of hornblende at middle crustal level (about 637℃ and 0.653 GPa) and mechanisms of deformation in the transitional regime are further discussed. Sheared hornblende rocks at middle crustal level have typical mylonitic microstructures, shown by coarse porphyroclasts and fine matrix grains. Different mineral phases in the rocks show distinct deformation characteristics. Hornblende and feldspar grains are intensely deformed with ob- vious grainsize reduction, but quartz grains are recrystallized dominantly by grain growth. Hornblende grains show typical brittle-ductile transition nature. Initial crystallographic orientations of porphyro- clasts have strong effects on the behavior of grains during deformation. There are mainly two types of porphyroclasts, type I "hard" porphyroclasts and type II "soft" porphyroclasts, with [001] perpendicular and parallel to external shear stresses respectively. "Hard" porphyroclasts generally occur as compe- tent grains that are rarely deformed or sometimes deformed by fracturing and dislocation tangling. "Soft" porphyroclasts are highly deformed primarily by dislocation tangling (as shown in the cores of the porphyroclasts), but twinning, dislocation glide and climb probably due to hydrolytic weakening also contribute to dynamic recrystallization of the porphyroclasts into fine grains in the matrix. The micro- and submicrostructures of the two types of porphyroclasts and fine-grained matrix provide powerful evidence for the behavior of brittle-ductile transition of hornblende grains. It is concluded that twinning nucleation is one of the most important processes that operate during dynamic recrystalliza- tion of hornblende crystals at the brittle-ductile transition. (100) [001] twin gliding and dislocation creep (dislocation glide and climb) are mutually enhanced during twinning nucleation. As a newly discovered mechanism of dynamic recrystallization, it may have played more important roles than ever recognized during dynamic recrystallization of crystals with twins in the brittle-ductile transition.
基金Supported by the National Natural Science Foundation of China(Nos.41576057,41876092)。
文摘The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.
文摘Rocks of the late Neoproterozoic Askaoun pluton (558 ± 2 Ma) located in the Ouzellarh-Sirwa promontory (Anti-Atlas) include magmatic microgranular enclaves (MMEs) ranging from rounded to ovoid in shape, dark and fine grained and generally 5 to 10 cm in size, some reaching a size of 50 cm. They are composed of microdiorite, quartz microdiorite and micromonzodiorite, whereas the felsic host rocks comprise mainly quartz-diorite and amphibole-biotite granodiorite based on mineralogical compositions. The mineral assemblage is similar to those described in their hosting granitoids but with different proportions. In this study composition of minerals is used to describe the nature of the magma and estimate the pressure, temperature and oxygen fugacity at which Askaoun pluton is emplaced. Based on chemistry of biotite Askaoun pluton formed from calc-alkaline magma. Compositions of plagioclase (An5 - An29);hornblende (Mg ≠= 0.59 - 0.65) and biotite (Mg ≠= 0.49 - 0.55) of MMEs are slightly distinct or similar to those of host rocks (An7-40;hbl Mg ≠= 0.64 - 0.69;Bi Mg ≠= 0.49 - 0.50) which suggest partial to complete equilibration during mafic-felsic magma interaction. The coexisting hornblende and plagioclase (hornblende-plagioclase thermometry), Al content in hornblende (aluminum-in-hornblende barometry) and the assemblage titanite-magnetite-quartz were used to constrain the P, T and fO2 during the crystallization of the parent magmas. The Askaoun pluton was emplaced at temperature ca. 504°C - 633°C and at pressure ca. 0.9 - 4.66 ± 0.6 Kbars (average depth = 6.5 km) from a highly oxidized magma (log fO2 = ?24.8 to ?19.2).
文摘There is a zone of blastomylonites containing hornblende gneisses of Lewisian Inliertype in the northeast-east of Yell,Shetland.This zone with a north—northwesterlytrend consists of blastomylonised hornblende-banded gneiss,hornblende-feldspar gneissand mica-felsie-gneiss with lenses of hornblende gneiss.It is indicated that theblastomylonite zone is actually a ductile shear zone and the sense of shear is dextral.This contributes to understanding the details of tectonic evolution in this area,and thiszone is probably a part of tectonic system of the British Caledonides.
文摘The present work is a petrological study of the gabbroic rocks of wadi Shianite Southeastern Desert of Egypt. Chemical analyses for major and trace elements showed that there are 3 main gabbro types. These are: 1)?pyroxene hornblende gabbronorite;?2) hornblende gabbro;?and 3) anorthosite.?The opaque minerals study of the gabbroic rocks showed that they composed mainly of ilmenite, magnetite and sulphides. The present gabbroic rocks work are related to calc-alkaline magma type, similar to the younger gabbros in other areas in the Eastern Desert.
文摘The geology of the Zango-Daji area was investigated petrographically and geochemically to determine the study area’s rock types and mineralization potential.The study area is underlain by rocks of the basement complex characterized by hilly and undulating rocks,which include granitic gneiss,migmatite gneiss,biotite hornblende granite gneiss,and pegmatites.Observation from the field shows that the study area is dominantly underlain by granitic gneiss.The granitic gneiss is dark grey,medium-coarse-grained,and characterized by weak foliation defined by the alignment of a streak of light and dark coloured minerals.They are widespread in the area constituting about 70%of rock types found in the study area.The average modal percentage of minerals in the rocks from petrographic studies shows that granitic gneiss had quartz 45%,plagioclase 10%,microcline 20%,hornblende 2%,biotite 10%,muscovite 5%,kyanite 8%and other minerals 5%.Also,the pegmatite of the study area has no evidence of mineralization;it contains minerals like quartz,feldspars(microcline and orthoclase),and micas(mostly muscovite).Geochemical analysis of the granitic gneiss of the study area shows that silica is by far the most abundant with a value of 53.5%,Na_(2)O value of 32.5%,Al_(2)O_(3),and k_(2)O of 6.1%and 4.0%,respectively.CaO value of 2.630%accounts for plagioclase feldspar in the granitic gneiss.The QAP diagram was used to determine the petrogenesis of the granitic gneiss.The plot shows the parent rock was a monzogranite with a low percentage of plagioclase in a thin section with a high percentage of quartz and alkali feldspar.The pegmatites of the study area are barren,as confirmed by the XRD result.
文摘Isotope dating, hornblende geobarometer, fission-track analysis and fluid inclusion homogeneous temperature analysis have been applied to Caledonian, Variscan and Yenshan plutons in Bei Huaiyang (BHY) and Dabie erogenic belt (DOB), and the emplaced depths and ages of these plutons have been obtained in order to obtain differential uplift time and uplift heights between BHY and DOB since late Paleozoic era. BHY had experienced three stages of uplift (C1-C2, T-J2, J3-K1) and its total uplift height is about 10 km, but, DOB had only experienced two stages of uplift (T-J2, J3-K1) and its maximum uplift height is more than 15 km. BHY uplift occurred mainly before the mid-Jurassic (about 150 Ma), but DOB uplift took place after the mid-Jurassic (about 150 Ma).
文摘The Jialuhe basic-intermediate intrusion is situated inside of the Xiangjia'nanshan granitic batholith at the eastern end of the East Kunlun orogenic belt. It is mainly composed of hornblende gabbro and quartz diorite. LA —ICP— MS zircon U —Pb dating showed that the Jialuhe intrusion was emplaced at 220 Ma. The rocks have low SiO2 (47. 91%-58. 92%) and Al2O3 (15. 54 %-18. 35%) contents, low A/CNK(0. 70-0. 90) ratios, high Mg^#(46- 61), and display metaluminous middle-K calc - alkaline affinities.
