DOI: 10.1007/s00531-015-1149-3
Scopus记录号: 2-s2.0-84935841038
论文题名: The multistage crystallization of zircon in calc-alkaline granitoids: U–Pb age constraints on the timing of Variscan tectonic activity in SW Iberia
作者: Pereira M.F. ; Chichorro M. ; Moita P. ; Santos J.F. ; Solá A.M.R. ; Williams I.S. ; Silva J.B. ; Armstrong R.A.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2015
卷: 104, 期: 5 起始页码: 1167
结束页码: 1183
语种: 英语
英文关键词: Crustal- and mantle-derived magmas
; Early Carboniferous
; Igneous zircon
; Intra-orogenic extension
; Ossa-Morena Zone
; U–Th–Pb SHRIMP data
Scopus关键词: calc alkaline rock
; crystallization
; geochronology
; granitoid
; Hercynian orogeny
; SHRIMP dating
; uranium-lead dating
; zircon
; Iberian Peninsula
; Ossa Morena Zone
英文摘要: CL imaging and U–Th–Pb data for a population of zircons from two of the Évora Massif granitoids (Ossa-Morena Zone, SW Iberia) show that both calc-alkaline granitoids have zircon populations dominated by grains with cores and rims either showing or not showing differences in Th/U ratio, and having ages in the range ca. 350–335 Ma (Early Carboniferous). Multistage crystallization of zircon is revealed in two main growth stages (ca. 344–342 Ma and ca. 336–335 Ma), well represented by morphologically complex zircons with cores and rims with different ages and different Th/U ratios that can be explained by: (1) crystallization from melts with different compositions (felsic peraluminous to felsic-intermediate metaluminous; 0.001 < Th/U ratio < 0.5) and (2) transient temperature fluctuations in a system where anatectic felsic melts periodically underwent injection of more mafic magmas at higher temperatures. The two studied calc-alkaline granitoids do not include inherited zircons (pre-Carboniferous), probably because they were formed at the highest grade of metamorphism (T > 837 °C; granulite facies) and/or because they were derived from inheritance-poor felsic and mafic rocks from a previous cycle, as suggested by the internal structures of zircon cores. These Variscan magmatic rocks with crystallization ages estimated at ca. 336–335 Ma are spatially and temporally related to high-temperature metamorphism, anatexis, processes of interaction between crustal- and mantle-derived magmas and intra-orogenic extension that acted in SW Iberia during the Early Carboniferous. © 2015, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84935841038&doi=10.1007%2fs00531-015-1149-3&partnerID=40&md5=3162ef53267937696b480d5bade56c11
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70276
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: IDL/Departamento de Geociências, ECT, Universidade de Évora, Évora, Portugal; CiCEGE/Departamento de Ciências da Terra, Universidade Nova de Lisboa, Lisbon, Portugal; Centro de Geofísica de Évora/Departamento de Geociências, ECT, Universidade de Évora, Évora, Portugal; Geobiotec, Departamento de Geociências da, Universidade de Aveiro, Aveiro, Portugal; LNEG, Unidade de Geologia e Cartografia Geológica, Porto, Portugal; Research School of Earth Sciences, The Australian National University, Acton, Australia; IDL/Departamento de Geologia, Universidade de Lisboa, Lisbon, Portugal
Recommended Citation:
Pereira M.F.,Chichorro M.,Moita P.,et al. The multistage crystallization of zircon in calc-alkaline granitoids: U–Pb age constraints on the timing of Variscan tectonic activity in SW Iberia[J]. International Journal of Earth Sciences,2015-01-01,104(5)