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Koshi Yamamoto - One of the best experts on this subject based on the ideXlab platform.

  • zircon u pb ages and geochemistry of devonian a type granites in the iraqi zagros suture zone damamna area new evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

  • Zircon U–Pb ages and geochemistry of Devonian A-type granites in the Iraqi Zagros Suture Zone (Damamna area): New evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

Imad Kadhim Abdulzahra - One of the best experts on this subject based on the ideXlab platform.

  • zircon u pb ages and geochemistry of devonian a type granites in the iraqi zagros suture zone damamna area new evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

  • Zircon U–Pb ages and geochemistry of Devonian A-type granites in the Iraqi Zagros Suture Zone (Damamna area): New evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

Hazel J. Chapman - One of the best experts on this subject based on the ideXlab platform.

  • The origin of Pyrenean Hercynian volcanic rocks (France-Spain): REE and SmNd isotope constraints — Comments
    Chemical Geology, 1995
    Co-Authors: Jennie S. Gilbert, Michael J. Bickle, Hazel J. Chapman
    Abstract:

    Abstract The Hercynian Orogeny of the Pyrenees generated a suite of basalt to rhyolite calc-alkaline volcanic rocks that were erupted subaerially. These melts may either have been generated above a subduction zone or by lower-crustal melting after input of mantle-derived magmas in an extensional environment. SmNd garnet/whole-rock mineral isochrons date a rhyolitic ignimbrite from the Coll de Oli Ignimbrite Member at 313±14 Ma (2σ) (MSWD=0.7) and a rhyolitic lava of the Coll de Pi region at 320±2 Ma (2σ) (MSWD=0.2). These ages suggest that some of the volcanism was synchronous with high-temperature, low-pressure metamorphism and partial melting deep in the Hercynian crust as seen in rocks now exposed in the axial and northern Pyrenean zones and dated by UPb on zircon at between 309±5 and 315±5 Ma. The silicic volcanic rocks are peraluminous and have highly fractionated REE patterns with low abundances of the HREE and ( La Yb ) n ≈70 . Mineral and whole-rock REE abundances suggest derivation of the silicic rocks by partial melting of a metasedimentary source in equilibrium with garnet and/or garnet fractionation in melts derived from peraluminous sources. Nd isotope compositions of the entire volcanic rock suite (mafic-silicic compositions) are within the same range as those of sediments metamorphosed during the Hercynian Orogeny and Hercynian basement rocks. They have mid-Proterozoic depleted-mantle model SmNd ages and do not exhibit mixing trends with mantle sources. Even the most mafic of the volcanic rocks appear to have interacted extensively with the crust. Analysis of the chemistry of the volcanic rocks does not unequivocally constrain the Hercynian tectonic setting of the Pyrenees.

  • The origin of Pyrenean Hercynian volcanic rocks (France-Spain): REE and SmNd isotope constraints
    Chemical Geology, 1994
    Co-Authors: Jennie S. Gilbert, Michael J. Bickle, Hazel J. Chapman
    Abstract:

    The Hercynian Orogeny of the Pyrénées generated a suite of basalt to rhyolite calc-alkaline volcanic rocks that were erupted subaerially. These melts may either have been generated above a subduction zone or by lower-crustal melting after input of mantle-derived magmas in an extensional environment. Sm---Nd garnet/whole-rock mineral isochrons date a rhyolitic ignimbrite from the Coll de Olí Ignimbrite Member at 313±14 Ma (2σ) (MSWD=0.7) and a rhyolitic lava of the Coll de Pi region at 320±2 Ma (2σ) (MSWD=0.2). These ages suggest that some of the volcanism was synchronous with high-temperature, low-pressure metamorphism and partial melting deep in the Hercynian crust as seen in rocks now exposed in the axial and northern Pyrenean zones and dated by U---Pb on zircon at between 309±5 and 315±5 Ma. The silicic volcanic rocks are peraluminous and have highly fractionated REE patterns with low abundances of the HREE and . Mineral and whole-rock REE abundances suggest derivation of the silicic rocks by partial melting of a metasedimentary source in equilibrium with garnet and/or garnet fractionation in melts derived from peraluminous sources. Nd isotope compositions of the entire volcanic rock suite (mafic-silicic compositions) are within the same range as those of sediments metamorphosed during the Hercynian Orogeny and Hercynian basement rocks. They have mid-Proterozoic depleted-mantle model Sm---Nd ages and do not exhibit mixing trends with mantle sources. Even the most mafic of the volcanic rocks appear to have interacted extensively with the crust. Analysis of the chemistry of the volcanic rocks does not unequivocally constrain the Hercynian tectonic setting of the Pyrénées

Hossein Azizi - One of the best experts on this subject based on the ideXlab platform.

  • zircon u pb ages and geochemistry of devonian a type granites in the iraqi zagros suture zone damamna area new evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

  • Zircon U–Pb ages and geochemistry of Devonian A-type granites in the Iraqi Zagros Suture Zone (Damamna area): New evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

Yoshihiro Asahara - One of the best experts on this subject based on the ideXlab platform.

  • zircon u pb ages and geochemistry of devonian a type granites in the iraqi zagros suture zone damamna area new evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.

  • Zircon U–Pb ages and geochemistry of Devonian A-type granites in the Iraqi Zagros Suture Zone (Damamna area): New evidence for magmatic activity related to the Hercynian Orogeny
    Lithos, 2016
    Co-Authors: Imad Kadhim Abdulzahra, Ayten Hadi, Yoshihiro Asahara, Hossein Azizi, Koshi Yamamoto
    Abstract:

    Abstract The Damamna granite (DG) is located in the Shalair Valley area in northeast Iraq within the Sanandaj Sirjan Zone (SSZ). The zircon U–Pb ages for the DG rocks are 364–372 Ma, indicating crystallization of the granitic body. The DG rocks are A-type granites, hypersolvus and peraluminous. They are enriched in SiO2, alkalis, Ga/Al, Ga, Zr and Rb/Sr and depleted in CaO, MgO, Sr, P, and Ti. These rocks show steep REE patterns, with LREE enrichment relative to HREE ((La/Yb)N = 5.7–42.5) and pronounced negative Eu anomalies reflecting feldspar fractionation. The geochemical characteristics and relationships suggest that the DG rocks are anorogenic and were emplaced in an extensional tectonic regime having an OIB-like magma affinity. The DG rocks are characterized by low Y/Nb ratios (0.2–1.5) and positive eNd (371 Ma) values (+ 1.6 to + 4.2), which indicate a mantle origin. In the Y/Nb–Yb/Ta diagram, the DG rocks plot in the A1-type granite field, with slightly higher Y/Nb values and a tendency of transitioning from A1 to the nearby A2 field, which possibly indicates a slight crustal contamination effect. The isotopic and geochemical data suggest that a combination of enriched mantle source magma with crustal contamination and fractional crystallization contributed to the generation of the magma for the DG. The geochemical and geochronological results for the DG rocks in the SSZ suggest an extensional zone that probably represents an early stage of Neo-Tethys opening during the Late Devonian or earlier, and this was associated with the Hercynian Orogeny and tectono-magmatic activity in northern Arabia and northwestern Iran.