Document Type : Original Research Paper


1 Ph.D. student, Department of Geology, Nature science branch, Tabriz University, Iran

2 Instructor, Department of Geology, Payame Noor University, Tehran, Iran

3 Full professors, Department of Geology, Faculty of Nature Science, Tabriz University, Iran


The study area is located in the Ardabil province and in the north east of Meshkinshahr city.More than 200 small and large Eocene age dykes have outcrops in this area with basaltic, tephritic, andesitic and trachy andesit composition. Clinopyroxene, plagioclase, analcime and sometimes coarse olivine crystals are present in these rocks. Mineral chemistry studies suggested that clinopyroxene type in rocks is Diopside type. Existence of normal and reverse zoning in clinopyroxens deduces differentiation were effective factors on evolution of the rocks. Enriched elements Ti, Al, Na, and K of pyroxene core to the rim of the effect of metasomatism to in these rocks. Tectonomagmatic diagrams and compare the chemical composition of study area clinopyroxenes with other tectonic environment suggested that characteristics of alkaline rocks related to volcanic arc. According to geotermobarometric studies clinopyroxenes in study rocks formed at temperature 1150-1200ºC and pressure of 7-14 Kbars. The depth for generation of magma between 55-65 Km and average 60 Km estimated for these rocks.