Geochemistry and petrogenesis of volcanic associations in Zouzan area, East of Iran
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ORIGINAL PAPER
Geochemistry and petrogenesis of volcanic associations in Zouzan area, East of Iran Seyed Ali Mazhari 1
Received: 30 March 2015 / Accepted: 10 September 2015 # Saudi Society for Geosciences 2015
Abstract Eocene volcanism in the Zouzan area, NE of Lut block, Eastern Iran, is presented by compositional range of different volcanic rocks include basalts, basaltic andesites, andesites, and dacites. This magmatic assemblage exhibits high-K calc-alkaline affinities. The chemical variations of major and trace elements suggest key role for fractional crystallization of amphibole + clinopyroxene ± magnetite in the magmatic evolution of Zouzan volcanic rocks. All volcanic rocks display large-ion lithophile element (LILE) and light rare earth element (LREE) enrichment and negative high field strength element (HFSE) anomalies with high Ba/Nb, low Nb/Y, and high Zr/Nb ratios indicative of arc and subduction-related nature of their magmas. Geochemical data show that volcanic rocks have been formed from shallow level fractionation of an enriched mantle (most likely mixing of slab and OIB-like melts) during subduction of oceanic crust between Lut and Afghan blocks in Tertiary. Keywords Zouzan . Volcanic rocks . Lut block . Fractional crystallization . Iran . Subduction
Introduction The Lut block is located at the east of central Iranian microcontinent (CIM), one of the most important geological units of Iran (Fig. 1a). There are numerous magmatic rocks in
* Seyed Ali Mazhari [email protected]; [email protected] 1
Department of Geology, Payame Noor University, 19395-4697, Tehran, Iran
this block which were erupted from Jurassic to quaternary. Two episodes of volcanic activity are more obvious in the Lut block: widespread Eocene–Oligocene calc-alkaline volcanism which is followed by volumetrically minor, Miocene to Quaternary alkali basaltic magmas. More recently, several authors reported valuable data about volcanic petrogenesis of the Lut block, but most studies are focused on the late Cenozoic alkaline volcanism (Walker et al. 2009; Khodami et al. 2010; Saadat et al. 2010; Saadat and Stern 2011, 2012; Pang et al. 2012). Unfortunately, geochemical data about the major magmatic event (Ecocene–Oligocene) is scarce and is limited to some regional studies with inadequate analyzes (e.g., Karimpour et al. 2011). The understanding of volcanic rocks geochemical characteristics would lead to increase the knowledge about Iranian geology and in turn, will result great information about Alpine–Himalayan orogency. This paper presents the first scientific research and primary geochemical data for Zouzan volcanic rocks. The only geological record on the volcanic unit has been presented by geological map of Zouzan (Blourian and Safari 2005) which demonstrated petrographic description of different rocks. In the present paper, we provide detailed features of Zouzan volcanic rocks and explain their magmatic evolution on the basis of geochemical data.
Geological setting The study area is situated at the west of Zouzan town, 9
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