The inception of a Paleotethyan magmatic arc in Iberia  

作　　者：M.F.Pereira A.Castro C.Fernández 

机构地区：[1]IDL, Departamento de Geociências, ECT, Universidade de évora [2]Departamento de Geología, Universidad de Huelva [3]Departamento de Geodinámica y Paleontología, Universidad de Huelva

出　　处：《Geoscience Frontiers》2015年第2期297-306,共10页地学前缘（英文版）

基　　金：financial support that comes from the Research Projects "GOLD"(FCT-PTDC/GEO-GEO/2446/2012FCOMP-01-0124-FEDER-029192);"PLUVOLC"(No.CGL201022022)

摘　　要：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.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.

关 键 词：Permo-Carboniferous Calc-alkaline arc-related batholiths Pangaea Paleotethys subduction Variscan and Cimmerian cycles 

分 类 号：P588.11[天文地球—岩石学]