Petrological, geochimical and geochronological studies have been completed in the area of Ekincik-Büyükkaraagaç (Est from Marmaris). The most important results are the followings: the ultrabasics strongly intruded from doleritic dykes are of MORB-type; the dykes are older than Cenomanien. Two younger phases of deformations have been recognized. The paleotectonic modell is in favor of a passiv margin on the southern side of the Menderès and an active one on the north where the Izmir-Ankara zone underthrusts the crystralline basement north-south wards.