DOI: 10.1007/s00531-013-0897-1
论文题名: The magmatic record in the Arghash region (northeast Iran) and tectonic implications
作者: Alaminia Z. ; Karimpour M.H. ; Homam S.M. ; Finger F.
刊名: International Journal of Earth Sciences
出版年: 2013
卷: 102, 期: 6 起始页码: 1603
结束页码: 1625
语种: 英语
英文关键词: Arghash Massif
; Geochemistry
; Granitoids
; Magmatism
; NE Iran
; U-Pb dating
Scopus关键词: backarc basin
; Cretaceous
; diorite
; geochronology
; Gondwana
; granitoid
; hornblende
; igneous geochemistry
; island arc
; isotopic composition
; magmatism
; Miocene
; Oligocene
; pluton
; Precambrian
; tectonic setting
; uranium-lead dating
; Iran
英文摘要: The area of Arghash in northeast Iran, prominent for its gold mineralization, was newly mapped on a scale of 1:20,000 with particular attention to the occurring generations of igneous rocks. In addition, geochronological and geochemical investigations were carried out. The oldest geological unit is a late Precambrian, hornblende-bearing diorite pluton with low-K composition and primitive isotope signatures. This diorite (U-Pb zircon age 554 ± 6 Ma) is most likely a remnant from a Peri-Gondwana island-arc or back-arc basin. About one-third of the map area is interpreted as an Upper Cretaceous magmatic arc consisting of a volcanic and a plutonic part. The plutonic part is represented by a suite of hornblende-bearing medium-K, I-type granitoids (minor diorite, mainly quartz-monzodiorite and granodiorite) dated at 92.8 ± 1.3 Ma (U-Pb zircon age). The volcanic part comprises medium-K andesite, dacite and tuffitic rocks and must be at least slightly older, because it is locally affected by contact metamorphism through the hornblende-granitoids. The Upper Cretaceous arc magmatism in the Arghash Massif is probably related to the northward subduction of the Sabzevar oceanic basin, which holds a back-arc position behind the main Neotethys subduction front. Small occurrences of pillow basalts and sediments (sandstone, conglomerate, limestone) tectonically intercalated in the older volcanic series may be relics of earlier Cretaceous or even pre-Cretaceous rocks. In the early Cenozoic, the Cretaceous magmatic arc was intruded by bodies of felsic, weakly peraluminous granite (U-Pb zircon age 55.4 ± 2.3 Ma). Another strong pulse of magmatism followed slightly later in the Eocene, producing large masses of andesitic to dacitic volcanic rocks. The geochemistry of this prominent Eocene volcanism is very distinct, with a high-K signature and trace element contents similar to shoshonitic series (high P, Zr, Cr, Sr and Ba). High Sr/Y ratios feature affinities to adakite magmas. The Eocene magmatism in the Arghash Massif is interpreted as related to thermal anomalies in crust and mantle that developed when the Sabzevar subduction system collapsed. The youngest magmatic activities in the Arghash Massif are lamprophyres and small intrusions of quartz-monzodiorite porphyries, which cut through all other rocks including an Oligocene-Miocene conglomerate cover series. © 2013 Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84881616146&doi=10.1007%2fs00531-013-0897-1&partnerID=40&md5=dbc40b0cc814abb1a4524b9a6889337c
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70522
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: Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran; Research Center for Ore Deposits of Eastern Iran, Ferdowsi University of Mashhad, Mashhad, Iran; Fachbereich Materialforschung und Physik, Universität Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
Recommended Citation:
Alaminia Z.,Karimpour M.H.,Homam S.M.,et al. The magmatic record in the Arghash region (northeast Iran) and tectonic implications[J]. International Journal of Earth Sciences,2013-01-01,102(6)