This paper presents a compilation of recent U-Pb （zircon） ages of late Carboniferous-early Permian （LC EP） calc-alkaline batholiths from lberia, together with a petrogenetic interpretation of magma generation base...This paper presents a compilation of recent U-Pb （zircon） ages of late Carboniferous-early Permian （LC EP） calc-alkaline batholiths from lberia, together with a petrogenetic interpretation of magma generation based on comparisons with Mesozoic and Tertiary Cordilleran batholiths and experimental melts. Zircon U-Pb ages distributed over the range ca. 315-280 Ma, indicate a linkage between calc-alkaline magmatism, Iberian orocline generation and Paleotethys subduction. It is also shown that Iberian LC-EP calcalkaline batholiths present unequivocal subduction-related features comparable with typical Cordilleran batholiths of the Pacific Americas active margin, although geochemical features were partially obscured by local modifications of magmas at the level of emplacement by country rock assimilation. When and how LC-EP calc-alkaline batholiths formed in Iberia is then discussed, and a new and somewhat controversial interpretation for their sources and tectonic setting （plume-assisted relamination） is suggested. The batholiths are proposed to have formed during the subduction of the Paleotethys oceanic plate （Pangaea self-subduction） and, consequently, they are unrelated to Variscan collision. The origin of the Iberian batholiths is related to the Eurasian active margin and probably represents the inception of a Paleotethvan arc in the core of Pangaea.展开更多
Recently,large phase-change magnetoelectric response has been anticipated by a first-principles investigation of phases in the BiFeO_(3)–BiCoO_(3)perovskite binary system,associated with the existence of a discontinu...Recently,large phase-change magnetoelectric response has been anticipated by a first-principles investigation of phases in the BiFeO_(3)–BiCoO_(3)perovskite binary system,associated with the existence of a discontinuous morphotropic phase boundary(MPB)between multiferroic polymorphs of rhombohedral and tetragonal symmetries.This might be a general property of multiferroic phase instabilities,and a novel promising approach for room temperature magnetoelectricity.We review here our current inves-tigations on the identification and study of additional material systems,alternative to BiFeO_(3)–BiCoO_(3)that has only been obtained by high pressure synthesis.Three systems,whose phase diagrams were,in principle,liable to show multiferroic MPBs have been addressed:the BiMnO_(3)–PbTiO_(3)and BiFeO_(3)–PbTiO_(3)binary systems,and the BiFeO_(3)–BiMnO_(3)–PbTiO_(3)ternary one.A compre-hensive study of multiferroism across different solid solutions was carried out based on electrical and magnetic characterizations,complemented with mechanical and electromechanical measurements.An in-depth structural analysis was also accomplished when necessary.展开更多
基金financial support that comes from the Research Projects "GOLD"(FCT-PTDC/GEO-GEO/2446/2012FCOMP-01-0124-FEDER-029192)"PLUVOLC"(No.CGL201022022)
文摘This paper presents a compilation of recent U-Pb （zircon） ages of late Carboniferous-early Permian （LC EP） calc-alkaline batholiths from lberia, together with a petrogenetic interpretation of magma generation based on comparisons with Mesozoic and Tertiary Cordilleran batholiths and experimental melts. Zircon U-Pb ages distributed over the range ca. 315-280 Ma, indicate a linkage between calc-alkaline magmatism, Iberian orocline generation and Paleotethys subduction. It is also shown that Iberian LC-EP calcalkaline batholiths present unequivocal subduction-related features comparable with typical Cordilleran batholiths of the Pacific Americas active margin, although geochemical features were partially obscured by local modifications of magmas at the level of emplacement by country rock assimilation. When and how LC-EP calc-alkaline batholiths formed in Iberia is then discussed, and a new and somewhat controversial interpretation for their sources and tectonic setting （plume-assisted relamination） is suggested. The batholiths are proposed to have formed during the subduction of the Paleotethys oceanic plate （Pangaea self-subduction） and, consequently, they are unrelated to Variscan collision. The origin of the Iberian batholiths is related to the Eurasian active margin and probably represents the inception of a Paleotethvan arc in the core of Pangaea.
基金Spanish MINECO through the MAT2014-58816-R and MAT2011-2370projects.C.M.F-P.also acknowledges the financial aid of the Spanish FPI Program(BES 2012-053017).
文摘Recently,large phase-change magnetoelectric response has been anticipated by a first-principles investigation of phases in the BiFeO_(3)–BiCoO_(3)perovskite binary system,associated with the existence of a discontinuous morphotropic phase boundary(MPB)between multiferroic polymorphs of rhombohedral and tetragonal symmetries.This might be a general property of multiferroic phase instabilities,and a novel promising approach for room temperature magnetoelectricity.We review here our current inves-tigations on the identification and study of additional material systems,alternative to BiFeO_(3)–BiCoO_(3)that has only been obtained by high pressure synthesis.Three systems,whose phase diagrams were,in principle,liable to show multiferroic MPBs have been addressed:the BiMnO_(3)–PbTiO_(3)and BiFeO_(3)–PbTiO_(3)binary systems,and the BiFeO_(3)–BiMnO_(3)–PbTiO_(3)ternary one.A compre-hensive study of multiferroism across different solid solutions was carried out based on electrical and magnetic characterizations,complemented with mechanical and electromechanical measurements.An in-depth structural analysis was also accomplished when necessary.
