The Experts below are selected from a list of 11022 Experts worldwide ranked by ideXlab platform
P. Andonaegui - One of the best experts on this subject based on the ideXlab platform.
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Early Ordovician orogenic event in Galicia (NW Spain): evidence from U–Pb ages in the uppermost unit of the Ordenes Complex
Earth and Planetary Science Letters, 1999Co-Authors: Jacobo Abati, G. R. Dunning, Ricardo Arenas, F. Díaz García, P. González Cuadra, J. R. Martínez Catalán, P. AndonaeguiAbstract:New U–Pb data (zircon, monazite and rutile) obtained from rocks of the uppermost allochthon in the Variscan belt of NW Spain indicate that the hangingwall to the suture includes an allochthonous unit with a pre-Variscan tectonothermal evolution. This evolution is characterised by an Early Ordovician (498–500 Ma) bimodal magmatism followed almost immediately (493–498 Ma) by a Barrovian style metamorphism up to the granulite facies. The metamorphism subsequent to the igneous intrusions requires convergence and crustal thickening in order to generate the Barrovian facies pattern shown by the lithologies of the uppermost allochthon. The almost coeval magmatism and metamorphism, and the chemistry of the metabasites suggest an accretionary complex, probably related to a volcanic arc, as the most probable setting for the origin of the uppermost unit. The implications of the existence of Early Ordovician convergent plate boundaries are discussed in the context of Gondwana–Laurentia–Avalon interactions.
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Early Ordovician orogenic event in galicia nw spain evidence from u pb ages in the uppermost unit of the ordenes complex
Earth and Planetary Science Letters, 1999Co-Authors: Jacobo Abati, G. R. Dunning, Ricardo Arenas, Diaz F Garcia, Gonzalez P Cuadra, J Martinez R Catalan, P. AndonaeguiAbstract:New U–Pb data (zircon, monazite and rutile) obtained from rocks of the uppermost allochthon in the Variscan belt of NW Spain indicate that the hangingwall to the suture includes an allochthonous unit with a pre-Variscan tectonothermal evolution. This evolution is characterised by an Early Ordovician (498–500 Ma) bimodal magmatism followed almost immediately (493–498 Ma) by a Barrovian style metamorphism up to the granulite facies. The metamorphism subsequent to the igneous intrusions requires convergence and crustal thickening in order to generate the Barrovian facies pattern shown by the lithologies of the uppermost allochthon. The almost coeval magmatism and metamorphism, and the chemistry of the metabasites suggest an accretionary complex, probably related to a volcanic arc, as the most probable setting for the origin of the uppermost unit. The implications of the existence of Early Ordovician convergent plate boundaries are discussed in the context of Gondwana–Laurentia–Avalon interactions.
A B Kotov - One of the best experts on this subject based on the ideXlab platform.
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Early Ordovician alkali ultramafic zhilandy complex central kazakhstan structure and age of formation
Доклады Академии наук, 2019Co-Authors: R M Antonuk, Alexey A Tretyakov, K E Degtyarev, A B Kotov, р м антонюк, а а третьяков, к е дегтярев, а б котовAbstract:U–Pb geochronological study of amphibole-bearing quartz monzodiorites of the alkali-ultramafic Zhilandy complex in Central Kazakhstan, whose formation is deduced at the Early Ordovician era (479 ± 3 Ma). The obtained data indicate three stages of intra-plate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic stage of alkali syenites of the Karsakpay complex intrusion, Early Cambrian stage of ultramafic-gabbroid plutons of the Ulutau complex formation, and Late Cambrian–Early Ordovician stage of formation of the Zhilandy complex and Krasnomay complex intrusions.
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The Early Ordovician Alkaline-Ultramafic Zhilandy Complex of Central Kazakhstan: Structure and Geochronology
Doklady Earth Sciences, 2019Co-Authors: R. M. Antonyuk, Alexey A Tretyakov, K E Degtyarev, A B KotovAbstract:The first U–Pb dating of amphibole-bearing quartz monzodiorites from the alkaline-ultramafic Zhilandy Pluton in Central Kazakhstan gave an Early Ordovician age of 479 ± 3 Ma. The data obtained allow confident recognition of three stages of intraplate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic with intrusion of alkaline syenites of the Karsakpai Complex; Early Cambrian with emplacement of ultramafic–gabbro plutons of the Ulutau Complex; and late Cambrian–Early Ordovician with formation of the Zhilandy Pluton and the intrusions of the Krasnomai Complex.
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The Early Ordovician Alkaline-Ultramafic Zhilandy Complex of Central Kazakhstan: Structure and Geochronology
Doklady Earth Sciences, 2019Co-Authors: R. M. Antonyuk, Alexey A Tretyakov, K E Degtyarev, A B KotovAbstract:The first U–Pb dating of amphibole-bearing quartz monzodiorites from the alkaline-ultramafic Zhilandy Pluton in Central Kazakhstan gave an Early Ordovician age of 479 ± 3 Ma. The data obtained allow confident recognition of three stages of intraplate magmatism in the western part of the Central Asian Orogenic Belt: Late Neoproterozoic with intrusion of alkaline syenites of the Karsakpai Complex; Early Cambrian with emplacement of ultramafic–gabbro plutons of the Ulutau Complex; and late Cambrian–Early Ordovician with formation of the Zhilandy Pluton and the intrusions of the Krasnomai Complex.
Axel Gerdes - One of the best experts on this subject based on the ideXlab platform.
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an Early Ordovician tonalitic granodioritic belt along the schistose greywacke domain of the central iberian zone iberian massif variscan belt
Geological Magazine, 2012Co-Authors: Alvaro Rubioordonez, L. G. Corretgé, G. Gallastegui, Pablo Valverdevaquero, A Cuestafernandez, M Fernandezgonzalez, Axel GerdesAbstract:The Zarza la Mayor and Zarza de Montanchez tonalites and Arroyo de la Luz granodiorite are part of a tonalitic–granodioritic belt located along the Schistose-Greywacke Domain of the Central Iberian Zone. These intrusions are also part of the Central Extremadura Batholith, a set of plutons ranging from tonalite to leucogranite that have been considered a prime example of Variscan syn-kinematic plutonism. New LA-ICP-MS and CA-ID-TIMS U–Pb dating reveals that the Zarza la Mayor tonalite–granodiorite is an Early Ordovician intrusion. The LA-ICP-MS data show that there is an absence of inherited cores, despite some complex internal zoning with obvious resorption features in some of the zircon crystals. Dating of monazite and zircon by CA-ID-TIMS provides a concordant age of 478.1 ± 0.8 Ma. This age coincides with electron microprobe analysis (EMPA) monazite chemical ages for the Zarza de Montanchez (482 ± 10 Ma) and Arroyo de la Luz (470 ± 15 Ma) intrusions. These new data indicate the presence of an Early Ordovician belt of calc-alkaline tonalite–granodiorite in the Schistose-Greywacke Domain – the Beira Baixa–Central Extremadura tonalite–granodiorite belt – which resembles a continental magmatic arc. This belt is contemporaneous with the Ollo de Sapo magmatic event further north in the Central Iberian Zone.
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An Early Ordovician tonalitic–granodioritic belt along the Schistose-Greywacke Domain of the Central Iberian Zone (Iberian Massif, Variscan Belt)
Geological Magazine, 2012Co-Authors: Álvaro Rubio-ordóñez, Pablo Valverde-vaquero, L. G. Corretgé, A. Cuesta-fernández, G. Gallastegui, M. Fernández-gonzález, Axel GerdesAbstract:The Zarza la Mayor and Zarza de Montanchez tonalites and Arroyo de la Luz granodiorite are part of a tonalitic–granodioritic belt located along the Schistose-Greywacke Domain of the Central Iberian Zone. These intrusions are also part of the Central Extremadura Batholith, a set of plutons ranging from tonalite to leucogranite that have been considered a prime example of Variscan syn-kinematic plutonism. New LA-ICP-MS and CA-ID-TIMS U–Pb dating reveals that the Zarza la Mayor tonalite–granodiorite is an Early Ordovician intrusion. The LA-ICP-MS data show that there is an absence of inherited cores, despite some complex internal zoning with obvious resorption features in some of the zircon crystals. Dating of monazite and zircon by CA-ID-TIMS provides a concordant age of 478.1 ± 0.8 Ma. This age coincides with electron microprobe analysis (EMPA) monazite chemical ages for the Zarza de Montanchez (482 ± 10 Ma) and Arroyo de la Luz (470 ± 15 Ma) intrusions. These new data indicate the presence of an Early Ordovician belt of calc-alkaline tonalite–granodiorite in the Schistose-Greywacke Domain – the Beira Baixa–Central Extremadura tonalite–granodiorite belt – which resembles a continental magmatic arc. This belt is contemporaneous with the Ollo de Sapo magmatic event further north in the Central Iberian Zone.
F C Murphy - One of the best experts on this subject based on the ideXlab platform.
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an Early Ordovician age for the annascaul formation of the se dingle peninsula sw ireland
Journal of the Geological Society, 2000Co-Authors: Simon Todd, Carol Connery, Kenneth T. Higgs, F C MurphyAbstract:The phyllitic mudrocks, quartz wacke sandstones and melange units of the Annascaul Formation in the SE Dingle Peninsula, SW Ireland have been previously assumed to be Silurian in age, similar to overlying fossiliferous Wenlock rocks of the Ballynane Member. The contact between the Ballynane Member and the underlying Annascaul beds is either faulted or unconformable , and the Annascaul mudrocks contain two or more cleavages not present in the Silurian Ballynane and younger strata. The Ballynane Member is therefore differentiated from the Annascaul Formation by upgrading the proven Wenlock Ballynane beds to formational status. Grey and black mudrocks in the Annascaul Formation have yielded diagnostic palynomorph assemblages indicative of an Early Ordovician age. The Annascaul Formation invites comparison with similar Early Ordovician rocks, south of the putative trace of the Iapetus Suture, in SE and eastern Ireland, in the English Lake District, and in central Newfoundland.
Jacobo Abati - One of the best experts on this subject based on the ideXlab platform.
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Early Ordovician orogenic event in Galicia (NW Spain): evidence from U–Pb ages in the uppermost unit of the Ordenes Complex
Earth and Planetary Science Letters, 1999Co-Authors: Jacobo Abati, G. R. Dunning, Ricardo Arenas, F. Díaz García, P. González Cuadra, J. R. Martínez Catalán, P. AndonaeguiAbstract:New U–Pb data (zircon, monazite and rutile) obtained from rocks of the uppermost allochthon in the Variscan belt of NW Spain indicate that the hangingwall to the suture includes an allochthonous unit with a pre-Variscan tectonothermal evolution. This evolution is characterised by an Early Ordovician (498–500 Ma) bimodal magmatism followed almost immediately (493–498 Ma) by a Barrovian style metamorphism up to the granulite facies. The metamorphism subsequent to the igneous intrusions requires convergence and crustal thickening in order to generate the Barrovian facies pattern shown by the lithologies of the uppermost allochthon. The almost coeval magmatism and metamorphism, and the chemistry of the metabasites suggest an accretionary complex, probably related to a volcanic arc, as the most probable setting for the origin of the uppermost unit. The implications of the existence of Early Ordovician convergent plate boundaries are discussed in the context of Gondwana–Laurentia–Avalon interactions.
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Early Ordovician orogenic event in galicia nw spain evidence from u pb ages in the uppermost unit of the ordenes complex
Earth and Planetary Science Letters, 1999Co-Authors: Jacobo Abati, G. R. Dunning, Ricardo Arenas, Diaz F Garcia, Gonzalez P Cuadra, J Martinez R Catalan, P. AndonaeguiAbstract:New U–Pb data (zircon, monazite and rutile) obtained from rocks of the uppermost allochthon in the Variscan belt of NW Spain indicate that the hangingwall to the suture includes an allochthonous unit with a pre-Variscan tectonothermal evolution. This evolution is characterised by an Early Ordovician (498–500 Ma) bimodal magmatism followed almost immediately (493–498 Ma) by a Barrovian style metamorphism up to the granulite facies. The metamorphism subsequent to the igneous intrusions requires convergence and crustal thickening in order to generate the Barrovian facies pattern shown by the lithologies of the uppermost allochthon. The almost coeval magmatism and metamorphism, and the chemistry of the metabasites suggest an accretionary complex, probably related to a volcanic arc, as the most probable setting for the origin of the uppermost unit. The implications of the existence of Early Ordovician convergent plate boundaries are discussed in the context of Gondwana–Laurentia–Avalon interactions.
