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Antonio Castro - One of the best experts on this subject based on the ideXlab platform.
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the gabbro shoshonitic monzonite Granodiorite association of khankandi pluton alborz mountains nw iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
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The gabbro (shoshonitic)–monzonite–Granodiorite association of Khankandi pluton, Alborz Mountains, NW Iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
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production of Granodiorite melt by interaction between hydrous mafic magma and tonalitic crust experimental constraints and implications for the generation of archaean ttg complexes
Lithos, 2005Co-Authors: S Lopez, Antonio Castro, Antonio GarciacascoAbstract:Two-layer experiments where a hydrous mafic glass is attached to a powdered tonalite have been performed at conditions of 850 to 1000 8C and 6 to 10 kbar. The aim of these experiments is to simulate the effects of fluids released from a crystallizing hydrous magma emplaced within a tonalitic continental crust. This process has been inferred from field observations and geochemical relationships in Archaean cratons where the first K-rich granite batholiths were developed. The results of these experiments indicate that conditions of 950 8C and 6 kbar, about 50 vol.% of Granodiorite melt is generated in the tonalitic crust. The process implies the transfer of H2O, originally dissolved into the mafic melt, together with potassium to the adjacent tonalite. It is proposed that the Archaean Granodiorites (of tonalite–trondhjemite–Granodiorite (TTG) complexes) result of recycling of older tonalitic crust, and that their generation required the intrusion of mantle-derived mafic magmas. These mafic magmas are sanukitoid in composition and their water content is higher than the water coordinated by hydrous phases such as biotite and amphibole. A simple model to determine the fertility of granitic crust to produce new granite batholiths based on the water content of the hydrous mafic magmas emplaced into the continental crust is presented. This model indicates that for conditions prevailing in the lower and middle crust, the volume of granitic melt may be twice the volume of basic magma. D 2004 Elsevier B.V. All rights reserved.
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Origin of peraluminous granites and Granodiorites, Iberian massif, Spain: an experimental test of granite petrogenesis
Contributions to Mineralogy and Petrology, 1999Co-Authors: Antonio Castro, Alberto E. Patiño Douce, L. Guillermo Corretgé, Jesús D. De La Rosa, Mohammed El-biad, Hassan El-hmidiAbstract:The discrimination between potential source materials involved in the genesis of Iberian granites and Granodiorites, as well as the role of mantle-crust inter- actions, are examined using constraints imposed by melting experiments, melting-assimilation experiments and Sr-Nd isotope systematics. The Sr-Nd isotope re- lationships indicate the existence of diAerent genetic trends in which juvenile mantle materials are involved by diAerent mechanisms: (1) a source trend, traced by a particular evolution of the pre-Hercynian basement and indicating mantle participation at the time of sedimen- tation; (2) a set of magmatic trends traced by gabbro- tonalite-enclave-Granodiorite associations, implying the incorporation of new mantle material at the time of granite generation. These relationships strongly support a pure crustal origin for the peraluminous leucogranites, derived from partial melting of crustal protoliths, and a hybrid origin for the peraluminous Granodiorites. These Granodiorites are the most abundant granitic rocks of the Central Iberian zone (CIZ) of the Iberian massif, implying that processes of hybridisation by assimilation and/or magma mixing played an important role in granitoid production during the Hercynian orogeny. These hypotheses have been tested by means of melting and assimilation experiments. Melting experiments in the range 800-900 ∞C and at pressures of 3, 6, 10 and 15 kbar indicate that: (1) several potential source materials such as Bt-Ms gneisses and metagreywackes are suitable for the production of peraluminous leucogranite melts; (2) the melt compositions are always leucogranitic, re- gardless of pressure; (3) pressure exerts a strong influ- ence on the fertility of the source: experiments at 3 kbar produce more than 20 vol% of melt, compared with less than 5 vol% of melt produced at 10 and 15 kbar and at the same temperature. The melting-assimilation experi- ments carried out at 1000 ∞C and 4, 7 and 10 kbar and using a proportion of 50% gabbro and 50% gneiss give high melt proportions (more than 50 vol.%) and noritic residues. These melts have the composition of le- ucoGranodiorites, and overlap with part of the compo- sitional range of peraluminous Granodiorites of the Iberian massif. The generation of more mafic Granodiorites may be explained by the incorporation of some residual orthopyroxene to the Granodiorite mag- mas. The low solubility of Fe + Mg prevents the gen- eration of Granodiorite melts with more than 3 wt% of MgO + FeO at all crustal pressures. The large volumes of peraluminous, hybrid Granodiorites, produced by assimilation of crustal rocks by mantle magmas, imply that an important episode of crustal growth took place during the Late-Palaeozoic Hercynian orogeny in the Iberian massif.
Zahra Badrzadeh - One of the best experts on this subject based on the ideXlab platform.
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the gabbro shoshonitic monzonite Granodiorite association of khankandi pluton alborz mountains nw iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
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The gabbro (shoshonitic)–monzonite–Granodiorite association of Khankandi pluton, Alborz Mountains, NW Iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
Fernando Corfu - One of the best experts on this subject based on the ideXlab platform.
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the genesis of i and s type granitoid rocks of the early ordovician oledo pluton central iberian zone central portugal
Lithos, 2009Co-Authors: I M H R Antunes, A M R Neiva, Maria Manuela Silva, Fernando CorfuAbstract:Abstract The Early Ordovician Oledo pluton consists of four distinct granodioritic to granitic phase (G1–G4), which intruded a Cambrian schist-metagraywacke complex, but were themselves intruded by a Late Carboniferous pluton. ID-TIMS U–Pb ages for zircon and monazite from these granitic rocks indicate emplacements within a short period of time at 479–480 Ma. Granodiorite G1 is the most deformed rock with shear zones and deformation at the border. G1 and G3 contain fine-grained biotite tonalite and biotite Granodiorite microgranular enclaves, which are darker and richer in mafic minerals than the host Granodiorites. The geological, mineralogical, geochemical and Sr, Nd and O isotopic data show that tonalitic and granodioritic enclaves and host G1 are of I-type and were related predominantly by a fractional crystallization process. Least-square analysis of major elements and modelling of trace elements indicate that granodioritic enclaves and host G1 could be derived from the tonalitic enclave magma by fractional crystallization of plagioclase, grunerite, biotite and ilmenite. Granodiorite G2 is of hybrid origin. Most variation diagrams for granodioritic enclaves and host G3 Granodiorite and their biotites show linear trends. Modelling of major and trace elements of granodioritic enclaves indicate that they result from mixing of relatively primitive Granodiorite magma with magma derived from crustal melting. Tonalitic enclaves correspond to globules of a more mafic relatively primitive magma. Granite G4 has the most pronounced crustal signature and is of S-type.
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the genesis of i and s type granitoid rocks of the early ordovician oledo pluton central iberian zone central portugal
Lithos, 2009Co-Authors: I M H R Antunes, A M R Neiva, Maria Manuela Silva, Fernando CorfuAbstract:Abstract The Early Ordovician Oledo pluton consists of four distinct granodioritic to granitic phase (G1–G4), which intruded a Cambrian schist-metagraywacke complex, but were themselves intruded by a Late Carboniferous pluton. ID-TIMS U–Pb ages for zircon and monazite from these granitic rocks indicate emplacements within a short period of time at 479–480 Ma. Granodiorite G1 is the most deformed rock with shear zones and deformation at the border. G1 and G3 contain fine-grained biotite tonalite and biotite Granodiorite microgranular enclaves, which are darker and richer in mafic minerals than the host Granodiorites. The geological, mineralogical, geochemical and Sr, Nd and O isotopic data show that tonalitic and granodioritic enclaves and host G1 are of I-type and were related predominantly by a fractional crystallization process. Least-square analysis of major elements and modelling of trace elements indicate that granodioritic enclaves and host G1 could be derived from the tonalitic enclave magma by fractional crystallization of plagioclase, grunerite, biotite and ilmenite. Granodiorite G2 is of hybrid origin. Most variation diagrams for granodioritic enclaves and host G3 Granodiorite and their biotites show linear trends. Modelling of major and trace elements of granodioritic enclaves indicate that they result from mixing of relatively primitive Granodiorite magma with magma derived from crustal melting. Tonalitic enclaves correspond to globules of a more mafic relatively primitive magma. Granite G4 has the most pronounced crustal signature and is of S-type.
Mehraj Aghazadeh - One of the best experts on this subject based on the ideXlab platform.
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the gabbro shoshonitic monzonite Granodiorite association of khankandi pluton alborz mountains nw iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
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The gabbro (shoshonitic)–monzonite–Granodiorite association of Khankandi pluton, Alborz Mountains, NW Iran
Journal of Asian Earth Sciences, 2010Co-Authors: Mehraj Aghazadeh, Nematallah Rashidnejad Omran, M H Emami, Hossien Moinvaziri, Antonio Castro, Zahra BadrzadehAbstract:The Khankandi pluton forms part of a group of gabbro–Granodiorite intrusions in the Alborz Mountains of NW Iran. A petrographical and geochemical study of this plutonic association reveals the existence of several magmatic cycles with different origins and slight differences in age. The oldest cycle (C1) is represented by Granodiorites. A second cycle (C2) is formed by a gabbro–monzonite association, with a clear shoshonitic affinity, that dominates most of the intrusive volume. Gabbros and monzonites form a co-magmatic association. Zircons from the monzonites were analyzed by LA–ICP-MS for U–Pb dating. An average age of 28.9 Ma, ranging from 23.7 to 33.6 Ma was obtained. Gabbros, monzonites and Granodiorites share a nearly common isotopic ratio for Sr and Nd. Both initial Sr and Nd ratios are clustered within a narrow range from 0.7045 to 0.7047 for the 87Sr/86Sr ratio and eNd from 1.46 to 1.89. Comparison with experimental studies, together with mantle-like isotopic ratios and comparisons of REE patterns, points to an origin by variable melting rates from a common metasomatised mantle source for gabbros and monzonites. Melting of a subducted melange is suggested for the Granodiorite magmas predating the gabbro–monzonite intrusion. The two sources, a metasomatised mantle and ascending silicic plumes, are direct consequence of subduction.
I M H R Antunes - One of the best experts on this subject based on the ideXlab platform.
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the genesis of i and s type granitoid rocks of the early ordovician oledo pluton central iberian zone central portugal
Lithos, 2009Co-Authors: I M H R Antunes, A M R Neiva, Maria Manuela Silva, Fernando CorfuAbstract:Abstract The Early Ordovician Oledo pluton consists of four distinct granodioritic to granitic phase (G1–G4), which intruded a Cambrian schist-metagraywacke complex, but were themselves intruded by a Late Carboniferous pluton. ID-TIMS U–Pb ages for zircon and monazite from these granitic rocks indicate emplacements within a short period of time at 479–480 Ma. Granodiorite G1 is the most deformed rock with shear zones and deformation at the border. G1 and G3 contain fine-grained biotite tonalite and biotite Granodiorite microgranular enclaves, which are darker and richer in mafic minerals than the host Granodiorites. The geological, mineralogical, geochemical and Sr, Nd and O isotopic data show that tonalitic and granodioritic enclaves and host G1 are of I-type and were related predominantly by a fractional crystallization process. Least-square analysis of major elements and modelling of trace elements indicate that granodioritic enclaves and host G1 could be derived from the tonalitic enclave magma by fractional crystallization of plagioclase, grunerite, biotite and ilmenite. Granodiorite G2 is of hybrid origin. Most variation diagrams for granodioritic enclaves and host G3 Granodiorite and their biotites show linear trends. Modelling of major and trace elements of granodioritic enclaves indicate that they result from mixing of relatively primitive Granodiorite magma with magma derived from crustal melting. Tonalitic enclaves correspond to globules of a more mafic relatively primitive magma. Granite G4 has the most pronounced crustal signature and is of S-type.
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the genesis of i and s type granitoid rocks of the early ordovician oledo pluton central iberian zone central portugal
Lithos, 2009Co-Authors: I M H R Antunes, A M R Neiva, Maria Manuela Silva, Fernando CorfuAbstract:Abstract The Early Ordovician Oledo pluton consists of four distinct granodioritic to granitic phase (G1–G4), which intruded a Cambrian schist-metagraywacke complex, but were themselves intruded by a Late Carboniferous pluton. ID-TIMS U–Pb ages for zircon and monazite from these granitic rocks indicate emplacements within a short period of time at 479–480 Ma. Granodiorite G1 is the most deformed rock with shear zones and deformation at the border. G1 and G3 contain fine-grained biotite tonalite and biotite Granodiorite microgranular enclaves, which are darker and richer in mafic minerals than the host Granodiorites. The geological, mineralogical, geochemical and Sr, Nd and O isotopic data show that tonalitic and granodioritic enclaves and host G1 are of I-type and were related predominantly by a fractional crystallization process. Least-square analysis of major elements and modelling of trace elements indicate that granodioritic enclaves and host G1 could be derived from the tonalitic enclave magma by fractional crystallization of plagioclase, grunerite, biotite and ilmenite. Granodiorite G2 is of hybrid origin. Most variation diagrams for granodioritic enclaves and host G3 Granodiorite and their biotites show linear trends. Modelling of major and trace elements of granodioritic enclaves indicate that they result from mixing of relatively primitive Granodiorite magma with magma derived from crustal melting. Tonalitic enclaves correspond to globules of a more mafic relatively primitive magma. Granite G4 has the most pronounced crustal signature and is of S-type.
