Carbinatitic magmatism evidence in the Quaternary volcanic rocks in the west of Nowbaran, NW of Iran

Abstract

The fourteen numbers of ultrabasic volcanoes eruption in the west of Nowbaran are located in the west margin of Iranian central zone near to the Sanandaj-Sirjan zone. The combination of volcanic material consists mainly of low viscosity lava and in some cases pyroclastic material. According to the petrography and geochemical data, these rocks are nephelinite and melilite-nephelinite. Several chemical characterizations such as low content of SiO2, high rate of CaO and MgO, depleted from HFSE and enrichment of LILE, shown the magma originated from depleted mantle source. Ti and Nb negative anomalies presented the subduction component for this magma source. The Nawbaran magma with sodic-alkaline nature, formed within plate geodynamic environment. The geochemical evidences have shown the magma originated from enrichment garnet-lherzolite mantle with low partial melting (1-3%) in the 90 to 110 km depth of earth surface. Existence of mantle calcite, calcium rich apatite and perovskite whit the high rate of CaO and MgO in the rocks composition signed the carbonated component and carbonate metasomatism is candidate for the evolution of west Nawbaran young magmatism.

Keywords

• nephelinite
• carbonatite
• quaternary
• nawbara
• central iran