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Petrogenesis of subvolcanic rocks from the Khunik prospecting area, south of Birjand, Iran

Untertitel:Geochemical, Sr-Nd isotopic and U-Pb zircon constraints
Autoren:Samiee, Somayeh (Ferdowsi University of Mashhad (FUM)) Karimpour, Mohammad Hassan (Ferdowsi University of Mashhad (FUM)) Ghaderi, Majid (Tarbiat Modares University) Haidarian Shahri, Mohammad Reza (Ferdowsi University of Mashhad (FUM)) Kloetzli, UrsSantos, José Francisco (Universidade de Aveiro)

The Khunik prospecting area is located 106km south of Birjand in eastern Iran, and is considered as an epithermal gold prospecting area. The mineralization is related to subvolcanic rocks. There are several outcrops of subvolcanic intrusions in the area which intruded into Paleocene-Eocene volcanic rocks (andesite, trachy-andesite and pyroclastic rocks). Petrographic studies indicate that subvolcanic rocks consist mainly of diorite, monzonite, quartz-monzonite, monzodiorite and quartz-monzodiorite. Mineralogically, these rocks contain plagioclase, K-feldspar, amphibole, pyroxene, biotite and quartz. Geochemically, they have features typical of high-K calk-alkaline to shoshonitic and are metaluminous, and also belong to magnetite granitoid series (I-type). Primitive mantle normalized trace element spider diagrams display enrichment in LILE, such as Rb, Ba, and Cs, compared to HFSE. Chondrite-normalized REE plots show moderately LREE enriched patterns (7.45N/YbN87Sr/86Sr ratios (0.704196-0.704772) and εNdi values (+1.3 to +3.3) are compatible with an origin of the parental melts in a supra-subduction mantle wedge. Zircon U-Pb dating by LA-ICP-MS indicates the age of 38±1Ma (late Eocene) for subvolcanic units that are related to mineralization. A biotite granodiorite porphyry is the testimony of the youngest magmatic activity in the area, with an age of 31±1Ma (early Oligocene). The represented dates are interpreted as magmatic crystallization ages of subvolcanic intrusions.

Anzahl der Seiten:13
Journal Titel:Journal of Asian Earth Sciences
Digital Object Identifier (DOI):http://dx.doi.org/10.1016/j.jseaes.2015.09.023
Publikations Typ:Artikel
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