Geochemistry and petrogenesis of Eocene shoshonitic ‎and adakitic volcanic rocks in Sonajeel area ‎(Southeast of Heris, Eastern Azerbaijan)‎

Abstract

The studied area is located in the SE of Heris (Eastern Azerbaijan province) and the Alborz-Azerbaijan structural zone. The Eocene volcanic rocks in the area of under study show various compositions ranging from olivine basalt, hornblende basalt, basaltic andesite and andesite to trachy andesite. The studied basaltic rocks, except for amphibole types, which show calc-alkaline affinity, mainly have shoshonitic and the andesitic rocks are adakitic composition. According to primitive mantle and chondrite normalized spider and REE diagrams, the studied rocks are characterized by LILE and LREE enrichment and pronounced depletion in HFS elements. Based on geochemical data the basaltic rocks have been originated from different degrees partial melting of a heterogeneous lithospheric mantle that metasomatized by subduction agents. The adakitic rocks have been generated from partial melting of thickened potassic mafic lower crust that have been metamorphosed in eclogitic facies.

Keywords

• shoshonite
• adakite
• petrogenesis
• eocene
• sonajeel
• arasbaran