ИСТИНА

The Klyuchevskaya group of volcanoes (KGV) is located in the northern part of the Central Kamchatka Depression (CKD), Kamchatka and comprises four active and nine extinct volcanoes. This area has the highest magma production rate for any arc worldwide and many of its volcanoes were studied in considerable detail. However, some volcanoes of the KGV including Late-Pleistocene volcanoes Bolshaya Udina and Malaya Udina (Udina massif), Ostraya Zimina and Ovalnaya Zimina (Zimina massif), and Gorny Zub, situated in South-East part of KGV, were studied only on a reconnaissance basis and modern geochemical studies have not been carried out at all. Nevertheless, these volcanoes are closest to the arc trench and may hold information on geochemical across-arc source and fluid variations in response to the east-west subduction of the Pacific plate below Kamchatka. We present major and trace element data on rocks from these poorly studied volcanoes as well as on their older volcanic basement in order to constrain the East-West geochemical variations through KGV.