MULTIPLE MAGMA SOURCES FOR THE PERALKALINE GRANITOIDS AND RELATED ROCKS OF THE KHALDZAN BUREGTE GROUP OF MASSIFS, WESTERN MONGOLIA: ISOTOPIC (NEODYMIUM, STRONTIUM, AND OXYGEN) AND GEOCHEMICAL DATA

Abstract

The Khaldzan Buregte group of alkaline massifs was formed during seven intrusive phases and is confined to a large dike belt within Early Caledonian island-arc ophiolite and normal granite cutting the ophiolite. The uranium isotopic composition of the rock of the massif varies from +5 to +9. With respect to the ratio of compatible and incompatible trace element, the source of the alkaline rocks vary from those OIB. A two stage model was propose for the formation of khaldzan Bburgte group of alkaline massifs.