The First Discovery of Cambrian Volcanic Rocks and Plagiogranites in the Tekturmas Ophiolite Zone (Central Kazakhstan): Age and Composition

Abstract

The complex of felsic to intermediate volcanic rocks intruded by plagiogranitic bodies is first revealed in the western part of the Tekturmas ophiolite zone of Central Kazakhstan. The U–Pb (SIMS) geochronological study of one of the plagiogranitic bodies dated back to the Early Cambrian (537 ± 5 Ma) is conducted for the first time. The peculiarities of the volcanic rocks and the composition of plagiogranites indicate their formation in a suprasubduction setting within the Early Cambrian primitive volcanic island arc. The formation of this arc was not related to the evolution of the Ordovician oceanic structures, the complexes of which participate in the structure of the Tekturmas zone.