پترولوژي و ژئوشيمي سنگ هاي آتشفشاني منطقه ي كجور، جنوب نوشهر

Geochemistry and Petrology of Volcanic Rocks In Kojor Area, South of Noshahre

Submarine volcanic rocks with cretaceous age are situated in central Alborze mountain and located in Kojor area at 25 Km , south of Noshahre town. These rock are mainly composed A6 of pyroclastics (Aglomarate, Epiclastic & Autoclastic breccias, ) and lava flows (Olivine Basalt, Basalt,BasalticAndesite, Andesitic Basalt,....) . Petrogaphical and geochemical investigation on these rocks are shown sequentially exchange evidence such as: Fractional crystallization process, sieve texture, Resorption of some phenocrysts shown non-equilibrium conditions between melt and crystals during magma cooling in magma chamber. Geochemical characteristics indicated that these rocks located in the Alkaline domain.The highly enrichment of LREE and HREE in comparison with Chonderite and primitive mantel and to be present in WPB (with in plate basalt) domain shown they may have formed in an extentional tectonic regime.