Late Paleozoic Granitoids of Central Chukotka:Structural Position and Age Constraints

摘要

The Chukotka folded area (Mesozoides) formed during collision between the Chukotka microconti-nent (fragment of the Arctic Alaska—Chukotka minor plate) and the structures of the Siberian continent's active margin [1]. Granitoid magmatism is widely manifested within the limits of the Chukotka Mesozoides. The age of its manifestation is an arguable point due to an insufficient degree of geochronological knowledge. At present, most researchers distinguish at least three stages in the evolution of the Chukotka Mesozoides: 147-139, 127-100, and 82.4-78.8 Ma BP [2]. Granitoids of the first two stages pierce the metamorphic basement and Paleozoic-Mesozoic fold structures.