The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwa...The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwan Volcanic Zone(NTVZ). The magma chamber process in this region has not previously been elucidated in detail. In this paper, the textural and compositional features of plagioclase phenocrysts in basalt from the Tatun Volcanic Group(TTVG) were studied to restrict the dynamics of magma system. Results show that the magma melts in TTVG are mainly sourced from the underlying MORB-like mantle wedge but influenced by incorporation of subduction components, causing the elevated Sr/Y and Ba/Y ratios in magma melts. The subduction components are mainly transported in the form of sediment melt. The plagioclase phenocrysts in the TTVG volcanic rocks are generally coarsely core-sieved with a clear rim. The An contents in the rims of plagioclase are much lower than those of cores, and elevated FeO concentrations are detected in the plagioclase rims. We propose there exists a double-layer magma chamber in this region. The core of the plagioclase was crystalized in the deeper quiescent magma chamber(~21 km), which was subsequently partially dissolved during the ascent of magma melt under H_(2)O-undersaturated condition, forming the typical coarsely sieved texture and synneusis. When this crystal-rich melt migrates into the shallower chamber, water saturation is reached and more sodic plagioclase formed as the rim of phenocryst. Due to the considerably higher fO_(2) in the shallow chamber than in the deeper one, and the distribution of Fe between plagioclase and melt positively correlates with fO_(2), the FeO content in the plagioclase rim elevates in conjunction with increasing fO_(2).展开更多
As an important part of the early Mesozoic granites in the South Qinling tectonic belt(SQTB),the Guangtoushan pluton provides a material basis for research on the composition of magma sources and the effects of perite...As an important part of the early Mesozoic granites in the South Qinling tectonic belt(SQTB),the Guangtoushan pluton provides a material basis for research on the composition of magma sources and the effects of peritectic assemblage entrainment(PAE)on the changes in the granite composition.As shown by the results of LA-ICP-MS zircon U-Pb dating,the Guangtoushan pluton was emplaced during the Late Triassic(214-212 Ma)and was formed in the post-collision stage between the SQTB and the Yangtze plate.The collected samples had high SiO_(2)content and low Cr and Ni contents,indicating that the magmas did not undergo significant crust-mantle mixing during their evolution.The Guangtoushan granitoids were distributed along the trend line of magmatic fractional crystallization in the F-An-Or diagram.This result,combined with the relatively homogeneous Sr-Nd isotopic composition,implies that the Guangtoushan pluton underwent slight assimilation and contamination.As can be inferred from the comparison between the compositions of the Guangtoushan granitoids and various fluid-absent experimental melts,the magma sources of the Guangtoushan granitoids contain a variety of materials,such as graywackes,pyroclastic graywackes,and pelites and are not derived from lower crustal mafic rocks.The correlation between the maficity and the major and trace elements further indicates that the strongly peraluminous granitoids from the Guangtoushan pluton was formed by the partial melting of biotite-bearing crustal rocks and its magmatic evolution was accompanied by the entrainment of clinopyroxenes and accessory minerals.展开更多
The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the ti...The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization,which are strongly influenced by the cooling/uplift histories of the hosting intrusions.We performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong Peninsula.The zircon and apatite U-Pb ages are 156.9±1.2 and 137.2±2.4 Ma for the Linglong intrusion,129.9±1.0 and 125.0±3.8 Ma for the Qujia intrusion,119.5±0.7 and 117.2±1.8 Ma for the Liulinzhuang intrusion,118.6±1.0 and 111.6±1.6 Ma for the Nansu intrusion,respectively.The coupled zircon and apatite data of these granitoids indicate a slow cooling rate(11.9°C/Ma)in the Late Jurassic,and rapid uplift and cooling(35.8-29.2°C/Ma)in the Early Cretaceous.The dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong Peninsula.This implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.展开更多
基金funded by the Shandong Provincial Natural Science Foundation, China (No. ZR2019BD010)the National Natural Science Foundation of China (No. 42276085)+2 种基金Open Fund of the Key Laboratory of Marine Geology and Environment, Chinese Academy of Sciences (No. MGE2021KG01)Pilot National Laboratory for Marine Science and Technology (Qingdao) (No. JCZX202014)the Key Laboratory Submarine Geoscience and Prospecting Techniques, Ministry of Education, Ocean university of China。
文摘The Taiwan mountain belt, one of the youngest orogenies in the world, is caused by the collision of the Luzon arc with the Eurasian margin, which leads to post-collisional extension and magmatism in the Northern Taiwan Volcanic Zone(NTVZ). The magma chamber process in this region has not previously been elucidated in detail. In this paper, the textural and compositional features of plagioclase phenocrysts in basalt from the Tatun Volcanic Group(TTVG) were studied to restrict the dynamics of magma system. Results show that the magma melts in TTVG are mainly sourced from the underlying MORB-like mantle wedge but influenced by incorporation of subduction components, causing the elevated Sr/Y and Ba/Y ratios in magma melts. The subduction components are mainly transported in the form of sediment melt. The plagioclase phenocrysts in the TTVG volcanic rocks are generally coarsely core-sieved with a clear rim. The An contents in the rims of plagioclase are much lower than those of cores, and elevated FeO concentrations are detected in the plagioclase rims. We propose there exists a double-layer magma chamber in this region. The core of the plagioclase was crystalized in the deeper quiescent magma chamber(~21 km), which was subsequently partially dissolved during the ascent of magma melt under H_(2)O-undersaturated condition, forming the typical coarsely sieved texture and synneusis. When this crystal-rich melt migrates into the shallower chamber, water saturation is reached and more sodic plagioclase formed as the rim of phenocryst. Due to the considerably higher fO_(2) in the shallow chamber than in the deeper one, and the distribution of Fe between plagioclase and melt positively correlates with fO_(2), the FeO content in the plagioclase rim elevates in conjunction with increasing fO_(2).
基金funded by the State Key Program of National Natural Science of China(Grant No.41730426)the National Natural Science Foundation of China(Grant Nos.41872066,41702069 and 41602040)the Research Fund of Hebei Provincial Bureau of Geology and Mineral Resources(454-0601-YBN-DXXP)。
文摘As an important part of the early Mesozoic granites in the South Qinling tectonic belt(SQTB),the Guangtoushan pluton provides a material basis for research on the composition of magma sources and the effects of peritectic assemblage entrainment(PAE)on the changes in the granite composition.As shown by the results of LA-ICP-MS zircon U-Pb dating,the Guangtoushan pluton was emplaced during the Late Triassic(214-212 Ma)and was formed in the post-collision stage between the SQTB and the Yangtze plate.The collected samples had high SiO_(2)content and low Cr and Ni contents,indicating that the magmas did not undergo significant crust-mantle mixing during their evolution.The Guangtoushan granitoids were distributed along the trend line of magmatic fractional crystallization in the F-An-Or diagram.This result,combined with the relatively homogeneous Sr-Nd isotopic composition,implies that the Guangtoushan pluton underwent slight assimilation and contamination.As can be inferred from the comparison between the compositions of the Guangtoushan granitoids and various fluid-absent experimental melts,the magma sources of the Guangtoushan granitoids contain a variety of materials,such as graywackes,pyroclastic graywackes,and pelites and are not derived from lower crustal mafic rocks.The correlation between the maficity and the major and trace elements further indicates that the strongly peraluminous granitoids from the Guangtoushan pluton was formed by the partial melting of biotite-bearing crustal rocks and its magmatic evolution was accompanied by the entrainment of clinopyroxenes and accessory minerals.
基金supported by the Talent Research Project of Hebei Province(No.HBQZYCXY010)the National Natural Science Foundation of China-Shandong Joint Fund Program entitled“Control Mechanisms of Faults on Deep Gold Deposits in Jiaodong Peninsula”(No.U2006201)+1 种基金Isotopic analyses at the University of Alberta were supported by an NSERC discovery grant to D.G.Pearsonsupported by the National Natural Science Foundation of China(No.42103024)China Postdoctoral Science Foundation(Nos.2020T130618 and 2020M682516).
文摘The Mesozoic intrusions of the Jiaodong Peninsula,eastern China,host giant gold deposits.Understanding the genesis of these deposits requires the determination of the source of the parental auriferous fluid and the timing of gold mineralization,which are strongly influenced by the cooling/uplift histories of the hosting intrusions.We performed an integrated U-Pb geochronology study on both zircon and apatite from four major magmatic episodes of the Jiaodong Peninsula.The zircon and apatite U-Pb ages are 156.9±1.2 and 137.2±2.4 Ma for the Linglong intrusion,129.9±1.0 and 125.0±3.8 Ma for the Qujia intrusion,119.5±0.7 and 117.2±1.8 Ma for the Liulinzhuang intrusion,118.6±1.0 and 111.6±1.6 Ma for the Nansu intrusion,respectively.The coupled zircon and apatite data of these granitoids indicate a slow cooling rate(11.9°C/Ma)in the Late Jurassic,and rapid uplift and cooling(35.8-29.2°C/Ma)in the Early Cretaceous.The dramatically increased uplift and cooling period in the Early Cretaceous are contemporaneous with large-scale gold mineralization in the Jiaodong Peninsula.This implies that thermal upwelling of asthenosphere and related tectonic extension played an important role in gold remobilization and precipitation.