ژئوشیمی مجموعه‌ی پلوتونیک هشت سر کلیبر؛ شمالغرب ایران

Hasht-Sar Kaleybar mafic, ultramafic and syenitic dykes are surrounded by Majid Abad Formation, Palaeocene age, volcanic deposits. The suite is restricted within the Horand, Mahmud Abad and Mokhtekan thrust and reverse faults. Clinopyroxenites, the oldest unit of the suite, have tholeiitic volcanic arc character and have some similarities with tectonite layer of oceanic crust, like Group A pyroxenites of the Ronda massif, Spain. The surrounding gabbro is the calc-alkaline part of volcanic arc. Clinopyroxenes composition of the two above units, is comparable with oceanic post-cumulates. Quartz and nephelin syenitic dykes, the youngest unit, crop out interior of the mafic-ultramafic rocks. Shoshonitic, I-type and post-collisional affinities of the dykes determined by geochemical studies. Considering the geological position, the Hasht-Sar plutonic suite is probably related to the Secondary Palaeo-Tethys subduction events.