Petrology and geochemistry of the Lattan Mountain magmatic rocks in the Sanandaj–Sirjan Zone, west of Iran

Abstract

Igneous rocks are distributed in the Lattan Mountain area, the center part of Sanandaj–Sirjan Zone, west Iran. Based on the mineralogy and geochemical composition, these are subvolcanic, volcanic, and plutonic rocks. It includes basalts, andesitic basalt, and andesite, with porphyritic to microlithic porphyry and vitrophyric textures as well as dolerite, diorite, gabbro, and microdiorite with a varied granular, microgranular, intersertal, and intergranular textures. The chemical compositions indicated to calc-alkaline to transitional nature, enrichment in LIL elements (Rb, Ba, Th, U, and Pb), and depletion in Ti and Zr, as it is evident in spider diagrams normalized to a primitive mantle. In addition, samples have enrichments of LREE relative to HREE. The Rb-Sr whole-rock isochron of these magmatic rocks shows an age of 152 ± 14 Ma (late Jurassic). The initial 87Sr/86Sr (0.7047 to 0.7051) and 143Nd/144Nd ratios range from (0.512534 to 0.512710) and eNdt = − 0.1 to + 2.2 that indicated to BSE composition. Our results suggest that the magmas for the magmatic rocks were derived from metasomatized enriched MORB-like sources. These rocks were formed in an island arc setting during subduction and closure of the Neotethys oceanic lithosphere beneath the Iran microplate about 152 Ma.