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Yueheng Yang - One of the best experts on this subject based on the ideXlab platform.
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crust mantle interaction beneath the luxi block eastern north china craton evidence from coexisting mantle and crust derived enclaves in a quartz Monzonite pluton
Lithos, 2013Co-Authors: M Santosh, Fangfang Hu, Kuifeng Yang, Yueheng YangAbstract:Abstract The Laiwu quartz Monzonite in the Luxi Block of eastern North China Craton (NCC) is characterized by the presence of abundant plagioclase amphibolite and gabbro–diorite enclaves. Here we present LA-ICPMS zircon U–Pb ages which show that the host quartz Monzonite was emplaced at 129.8 ± 1.0 Ma, whereas the protolith of the plagioclase amphibolite enclaves formed during early Paleoproterozoic. The gabbro–diorite enclaves were produced simultaneously with or slightly earlier than the formation of the host quartz Monzonite. Combined with the Archean and Paleoproterozoic zircons as well as the low e Nd (0) values (− 18.4 to − 18.0) in the plagioclase amphibolite enclaves, the equilibrium temperature and pressure conditions (645–670 °C and 4.8–6.5 Kb) suggest that the plagioclase amphibolite enclaves are fragments of the middle crust. The gabbro–diorite enclaves mainly originated from an enriched lithospheric mantle metasomatized by melts/fluids derived from the continental crust, as indicated by their low SiO 2 (54.4–54.7 wt.%) and high MgO (10.9–11.1 wt.%) contents as well as the negative e Nd (t) values (− 13.5 to − 10.7) and enrichment of LILEs (e.g., Ba and Sr) and depletion of HFSEs (e.g., Nb, Ta, P and Ti). Compared with the ancient crustal rocks and the mafic plutons considered to have been derived from lithospheric mantle in the Luxi Block, the moderate e Nd ( t ) (− 15.7 to − 15.1) and e Hf ( t ) (− 20.7 to − 13.0) values of the quartz Monzonite in our study suggest that both mantle- and crust-derived melts were involved in the magma generation. Thus we propose a model involving magma mixing between mantle- and crust-derived melts for the formation of the quartz Monzonite. Since significant crust–mantle interaction is recorded not only in the quartz Monzonite and its enclaves in the Luxi Block but also in the other granitoids widespread in the NCC, it is considered that large-scale crust–mantle interaction and magmatic underplating were associated with the Mesozoic lithospheric mantle thinning and crustal reactivation in the eastern NCC.
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petrogenesis and tectonic significance of the 850 ma gangbian alkaline complex in south china evidence from in situ zircon u pb dating hf o isotopes and whole rock geochemistry
Lithos, 2010Co-Authors: Xuance Wang, Yu Liu, Yueheng YangAbstract:Abstract The Gangbian alkaline complex in the southeastern Yangtze Block (South China) is composed of Si-undersaturated pyroxene syenites and Si-saturated to -oversaturated syenites and quartz Monzonites. SIMS zircon U–Pb analyses indicate that the complex was emplaced at 848 ± 4 Ma, during a previously-recognized interval of magmatic quiescence between the ca 1.0–0.89 Ga Sibaoan orogenic magmatism and the ca 0.83–0.78 Ga magmatic flare-up. The Gangbian rocks are characterized by wide, coherent variations in major and trace elements (SiO2 = 47.6–68.4%, K2O + Na2O = 4.5–10.5%, K2O/Na2O = 0.4–1.2, MgO = 1.2–8.5%, Cr = 4.5–239 ppm, and Ni = 4.5–143 ppm) and by enrichment in LIL and LREE and depletion in Nb, Ta and P in trace element spidergrams. Their whole-rock eNd(T) (− 6.5 to − 0.4) and eHf(T) (− 10.7 to 0.4) are positively correlated, suggesting involvement of both metasomatized mantle and continental crust materials in their genesis. In situ zircon Hf–O isotopic measurements for the most evolved quartz Monzonite sample yield a binary mixing trend between the mantle- and supracrustal-derived melts. It is suggested that the pyroxene syenites were derived by partial melting of metasomatized, phlogopite-bearing lithospheric mantle, and the parental magma experienced extensive fractionation of pyroxene and olivine associated with varying degrees of crustal contamination. Subsequent fractional crystallization of hornblende and minor amounts of plagioclase from the alkali basaltic magmas, accompanied by crustal contamination, produced the Si-saturated to -oversaturated syenites and quartz Monzonites. These ca. 0.85 Ga alkaline rocks and neighboring contemporaneous dolerite dykes are the products of the anorogenic magmatism after the Sibao Orogeny. They post-date the final amalgamation between the Yangtze and Cathaysia Blocks, most likely manifesting the initial rifting of South China within the Rodinia supercontinent.
M Santosh - One of the best experts on this subject based on the ideXlab platform.
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gold hosting high ba sr granitoids in the xincheng gold deposit jiaodong peninsula east china petrogenesis and tectonic setting
Journal of Asian Earth Sciences, 2014Co-Authors: Zhongliang Wang, Liqiang Yang, Jun Deng, M Santosh, Huafeng Zhang, Ruihong Li, Tao Huang, Xiaoli Zheng, Hai ZhaoAbstract:Abstract The Xincheng deposit is the only large gold deposit with a proven reserve of >200 t gold hosted by the Early Cretaceous granitoids in northwest Jiaodong Peninsula, East China. The granitoids hosting this ore deposit comprise an inner medium- to fine-grained quartz Monzonite and an outer medium- to coarse-grained monzogranite with distinctive K-feldspar megacrysts. LA–ICP–MS zircon dating yields U–Pb ages of 128 ± 1 to 132 ± 1 Ma and 127 ± 2 to 129 ± 1 Ma, for the quartz Monzonite and the monzogranite, respectively. The Early Cretaceous ages obtained in our study are comparable with the 126–130 Ma age range reported for the Guojialing granitic suite. The monzogranites, typical high Ba–Sr granites, possess high SiO2 (70.89–73.35%), K2O (3.85–4.32%), total alkalis (K2O + Na2O = 8.08–8.68%), Sr (634–888 ppm), Ba (1395–2111 ppm) and LREE (59.43–145.88), with low HREE and HFSE contents and insignificant Eu anomalies. The rocks display markedly high Sr/Y (114–297) and (La/Yb)N (20–79) ratios. They have low MgO (0.23–0.62%), Cr (0.4–8.33 ppm) and Ni (0.47–2.92 ppm) contents. The typical high Ba–Sr signatures of the outer acidic monzogranites are also shared by the inner intermediate-acidic quartz Monzonites, with a relatively higher abundance of these elements. The plagioclases in the quartz Monzonites and monzogranites are oligoclase–andesine with An contents of 11.7–44.5%, and oligoclase with An contents of 12.9–29.3%, respectively, which both show the reverse zoning texture. The quartz Monzonites have zircon eHf(t) values of −21.3 to −13.9 (average −18.7), which are less negative and show larger variations than those of the monzogranites (eHf(t) = −24.7 to −18.1, average −19.5). Detailed elemental, mineralogical and isotopic data suggest that the high Ba–Sr quartz Monzonites and monzogranites were most likely generated by partial melting of the basement rocks of the Jiaobei terrane accompanied by crustal assimilation, with minor addition of the intermediate magma derived from the partial melting of juvenile mafic lower crust formed by the earlier underplating of mantle magma, and the quartz Monzonites may represent the path of intermediate magma inputting into felsic magma. In combination with previous investigations, we suggest subduction of the paleo-Pacific slab beneath the North China Craton (NCC) and associated asthenosphere upwelling were most likely the mechanism associated with the generation of the high Ba–Sr granites.
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crust mantle interaction beneath the luxi block eastern north china craton evidence from coexisting mantle and crust derived enclaves in a quartz Monzonite pluton
Lithos, 2013Co-Authors: M Santosh, Fangfang Hu, Kuifeng Yang, Yueheng YangAbstract:Abstract The Laiwu quartz Monzonite in the Luxi Block of eastern North China Craton (NCC) is characterized by the presence of abundant plagioclase amphibolite and gabbro–diorite enclaves. Here we present LA-ICPMS zircon U–Pb ages which show that the host quartz Monzonite was emplaced at 129.8 ± 1.0 Ma, whereas the protolith of the plagioclase amphibolite enclaves formed during early Paleoproterozoic. The gabbro–diorite enclaves were produced simultaneously with or slightly earlier than the formation of the host quartz Monzonite. Combined with the Archean and Paleoproterozoic zircons as well as the low e Nd (0) values (− 18.4 to − 18.0) in the plagioclase amphibolite enclaves, the equilibrium temperature and pressure conditions (645–670 °C and 4.8–6.5 Kb) suggest that the plagioclase amphibolite enclaves are fragments of the middle crust. The gabbro–diorite enclaves mainly originated from an enriched lithospheric mantle metasomatized by melts/fluids derived from the continental crust, as indicated by their low SiO 2 (54.4–54.7 wt.%) and high MgO (10.9–11.1 wt.%) contents as well as the negative e Nd (t) values (− 13.5 to − 10.7) and enrichment of LILEs (e.g., Ba and Sr) and depletion of HFSEs (e.g., Nb, Ta, P and Ti). Compared with the ancient crustal rocks and the mafic plutons considered to have been derived from lithospheric mantle in the Luxi Block, the moderate e Nd ( t ) (− 15.7 to − 15.1) and e Hf ( t ) (− 20.7 to − 13.0) values of the quartz Monzonite in our study suggest that both mantle- and crust-derived melts were involved in the magma generation. Thus we propose a model involving magma mixing between mantle- and crust-derived melts for the formation of the quartz Monzonite. Since significant crust–mantle interaction is recorded not only in the quartz Monzonite and its enclaves in the Luxi Block but also in the other granitoids widespread in the NCC, it is considered that large-scale crust–mantle interaction and magmatic underplating were associated with the Mesozoic lithospheric mantle thinning and crustal reactivation in the eastern NCC.
Yuzhou Feng - One of the best experts on this subject based on the ideXlab platform.
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late stage southwards subduction of the mongol okhotsk oceanic slab and implications for porphyry cusbnd mo mineralization constraints from igneous rocks associated with the fukeshan deposit ne china
Lithos, 2019Co-Authors: Changzhou Deng, Jinsheng Han, Huayong Chen, Bing Xiao, Deyou Sun, Yuzhou FengAbstract:Abstract Multistage igneous rocks identified in the newly discovered Fukeshan porphyry Cu Mo deposit, NE China give new insights into the late-stage southwards subduction of the Mongol-Okhotsk oceanic slab (MOOS) and Cu Mo mineralization during the late Mesozoic. The U Pb ages of zircons from medium-grained monzogranite, coarse-grained monzogranite, ore-related quartz diorite porphyry, quartz Monzonite, ganodiorite porphyry, diorite porphyry and andesitic porphyry associated with the Fukeshan deposit are 192.7 ± 1.9, 192.2 ± 2.7, 148.7 ± 0.8, 148.8 ± 0.9, 144.1 ± 1.1, 144.9 ± 0.9, and 144.8 ± 1.3 Ma, respectively. The Early Jurassic coarse-grained monzogranite, Late Jurassic quartz Monzonite and quartz diorite porphyry, and Early Cretaceous granodiorite porphyry are characterized by low Yb and Y contents, and high Sr/Y ratios, indicating adakite affinities. The whole-rock geochemistry, and Sr Nd and zircon Hf isotopic features of the coarse-grained monzogranite and granodiorite porphyry indicate they were derived from the partial melting of a thickened basaltic lower crust. On the other hand, the quartz Monzonite and quartz diorite porphyry probably originated from the melting of oceanic crust together with assimilation of enriched mantle and continental crust. The medium-grained monzogranites were possibly derived from a basaltic lower crust at shallower depths, and the diorite porphyry and andesitic porphyry probably originated from a metasomatized mantle source. Considering the Early Jurassic–Early Cretaceous magmatism and regional tectonic evolution of the Erguna Block, we propose that the MOOS was subducted towards the south during the Early Jurassic (195–170 Ma), slab retreat occurred during the early Late Jurassic (165–155 Ma), oceanic ridge subduction took place during the Late Jurassic (150–147 Ma). The final closure of the Mongol-Okhotsk Ocean occurred during the Early Cretaceous (145–143 Ma). The southwards subduction of a ridge on the MOOS provided a favorable tectonic setting for Cu Mo mineralization, and this is accordance with the discovery of many Late Jurassic–Early Cretaceous porphyry Cu Mo deposits in the eastern part of the Erguna Block.
Deyou Sun - One of the best experts on this subject based on the ideXlab platform.
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late stage southwards subduction of the mongol okhotsk oceanic slab and implications for porphyry cusbnd mo mineralization constraints from igneous rocks associated with the fukeshan deposit ne china
Lithos, 2019Co-Authors: Changzhou Deng, Jinsheng Han, Huayong Chen, Bing Xiao, Deyou Sun, Yuzhou FengAbstract:Abstract Multistage igneous rocks identified in the newly discovered Fukeshan porphyry Cu Mo deposit, NE China give new insights into the late-stage southwards subduction of the Mongol-Okhotsk oceanic slab (MOOS) and Cu Mo mineralization during the late Mesozoic. The U Pb ages of zircons from medium-grained monzogranite, coarse-grained monzogranite, ore-related quartz diorite porphyry, quartz Monzonite, ganodiorite porphyry, diorite porphyry and andesitic porphyry associated with the Fukeshan deposit are 192.7 ± 1.9, 192.2 ± 2.7, 148.7 ± 0.8, 148.8 ± 0.9, 144.1 ± 1.1, 144.9 ± 0.9, and 144.8 ± 1.3 Ma, respectively. The Early Jurassic coarse-grained monzogranite, Late Jurassic quartz Monzonite and quartz diorite porphyry, and Early Cretaceous granodiorite porphyry are characterized by low Yb and Y contents, and high Sr/Y ratios, indicating adakite affinities. The whole-rock geochemistry, and Sr Nd and zircon Hf isotopic features of the coarse-grained monzogranite and granodiorite porphyry indicate they were derived from the partial melting of a thickened basaltic lower crust. On the other hand, the quartz Monzonite and quartz diorite porphyry probably originated from the melting of oceanic crust together with assimilation of enriched mantle and continental crust. The medium-grained monzogranites were possibly derived from a basaltic lower crust at shallower depths, and the diorite porphyry and andesitic porphyry probably originated from a metasomatized mantle source. Considering the Early Jurassic–Early Cretaceous magmatism and regional tectonic evolution of the Erguna Block, we propose that the MOOS was subducted towards the south during the Early Jurassic (195–170 Ma), slab retreat occurred during the early Late Jurassic (165–155 Ma), oceanic ridge subduction took place during the Late Jurassic (150–147 Ma). The final closure of the Mongol-Okhotsk Ocean occurred during the Early Cretaceous (145–143 Ma). The southwards subduction of a ridge on the MOOS provided a favorable tectonic setting for Cu Mo mineralization, and this is accordance with the discovery of many Late Jurassic–Early Cretaceous porphyry Cu Mo deposits in the eastern part of the Erguna Block.
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Late Palaeozoic igneous rocks of the Great Xing’an Range, NE China: the Tayuan example
2019Co-Authors: Jun Gou, Deyou Sun, Dong-guang Yang, Zong-yuan Tang, An-qi MaoAbstract:The Tayuan plutons located at the boundary of the Erguna and Xing’an blocks expose a coexisting mafic–felsic association that is made of monzogranite and gabbro-monzodiorite as well as subordinate quartz Monzonite. LA–ICP–MS U–Pb zircon dating revealed a synchronous emplacement of the monzogranite (314–317 Ma), gabbro (308–315 Ma), and quartz Monzonite (310 ± 3 Ma). The majority of these intrusions are characterized by an enrichment in light rare earth elements relative to heavy rare earth elements and a depletion of high strength field elements (e.g. Nb, Ta, Ti). Zircons from the gabbro and monzogranite have εHf(t) values of 1.1–9.6 and −3.0–3.3, respectively. Geochemical data show that the gabbro-monzodiorite may have been generated by the melting of a fluid-metasomatized lithospheric mantle, while the monzogranite may have been formed by a partial melting of the Mesoproterozoic crust. The quartz Monzonite has similar whole-rock geochemical and Hf isotopic compositions to those of the gabbros and could have been produced from the same mantle source as that from which the gabbros were extracted. The Tayuan plutonic rocks have high contents of K2O and total alkalis and show a northwestward polarity like that of the continental margin plutonic rocks along the Hegenshan–Heihe suture zone. Combined with data from published studies, our data indicate that the Tayuan intrusive rocks were generated by the northwestward subduction of the Hegenshan–Heihe Oceanic plate.
Zhen Li - One of the best experts on this subject based on the ideXlab platform.
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origin of mafic microgranular enclaves mmes and their host quartz Monzonites from the muchen pluton in zhejiang province southeast china implications for magma mixing and crust mantle interaction
Lithos, 2013Co-Authors: Zhen LiAbstract:Abstract The origin of mafic enclaves in granitoid plutons has long been a matter of debate. In this paper, we present detailed petrographic, mineralogical, geochemical, and Sr Nd Hf isotopic data, U Pb zircon dates, and field and petrological observations, for mafic microgranular enclaves (MMEs) and their host quartz Monzonites from the Muchen pluton in Southeast China to evaluate their origins. LA–ICP–MS U Pb dating of zircon yields crystallisation ages of 112.4 ± 1.2 Ma and 112.1 ± 1.0 Ma for the MMEs and host quartz Monzonites, respectively, indicating their coeval formation during the late Early Cretaceous. Field and petrological observations, such as spheroidal shapes, back-veining, double enclaves, xenocrysts, acicular apatites, and oscillatory zoning with repeated resorption surfaces in plagioclases, suggest that the MMEs are globules of a more mafic magma that was injected into and mingled with the host felsic magma. Geochemically, the host Monzonites are intermediate-acidic, metaluminous, alkaline, and K-rich. In contrast, the MMEs are relatively poor in Si and K. The host Monzonites are enriched in Rb, Th and U, and depleted in Sr, P, Nb, Ta and Ti, and show moderate to strong europium depletions (δEu = 0.12–0.60). These mineralogical and geochemical features classify the quartz Monzonites as belonging to the I-type granitoids. The MMEs have broadly similar trace element signatures to those of the host Monzonite, but are distinct in having relatively enriched Sr and P, more depleted Zr and Hf, and weak to moderate Eu depletions (δEu = 0.43–0.93). Major and trace element data plotted versus isotopic data for the MMEs and the host quartz Monzonites yield covariant arrays that result from magma mixing during their petrogenesis. The MMEs and the host quartz Monzonites have similar initial 87Sr/86Sr ratios (ISr) of 0.7058–0.7070 and 0.7062–0.7065, respectively, and both have high eNd(t) values (− 2.6 to + 0.6 for MMEs; − 3.2 to − 2.4 for quartz Monzonites). However, zircons from the MMEs have different eHf(t) values (− 0.4 to + 6.2) than the host quartz Monzonites (− 1.0 to + 1.8), indicating that the MMEs and host granitoids largely crystallised from different magmas, providing direct evidence for mafic–felsic magma mixing processes. The zircon saturation geothermometer and Al-in-hornblende geobarometer show that the Muchen pluton crystallised at temperatures of 797–851 °C and depths of 6–7 km. The integrated petrology, and elemental and isotopic compositions suggest that the MMEs and host quartz Monzonites were generated by mixing of depleted, mantle-derived, mafic magmas and felsic magmas produced by partial melting of crustal materials in an extensional setting.