Ab-e-garm village situated 85km to sw of Ghazvin, and the studied area located somewhere around. From geographical point of view this area is the Soltanieh mountains continuation in Kabudar Ahang geological quadrangle. Lower Cretaceous igneous rocks in this area consist of: spilitic basalt, alkali olivine basalt, basalt, mugearite and trachy-basalt, which would be seen as lava and tuff, and their intrusives are mostly, microgabbro, pyroxene hornblende gabbro and mela gabbro. These igneous rocks are of alkaline series. Good correlations and continuous trends of main element oxides vs. silica in chemical variation diagrams, confirm genetic relationship between different facies. Comparison of geochemical data and petrography of these rocks shows that seperation of OL, PX and magnetite caused parent magma differentiation, ended into formation of different terms from it. With respect to continental rifts abundances between small continent boundaries in Iran in lower Cretaceous time, it is possible that the lower Cretaceous igneous rocks of Ab-e-garm area be related to these rifts or back arc zone of oceanic crust subduction between these small continents, however,to distinguish exact history of Ab-e-garm area we do need much more data at this time.

Keywords: Ab-e-garm, Alkali olivine basalt, Alkaline series, Lower cretaceous

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