Volcanogens of marginal orogenic belts of the northwestern sector of Northeast Asia

Abstract

The tectonic position of the marginal orogenic volcanic belts of the northwestern sector of NE Asia is presented. Belts are formed by chains of volcanic fields – volcanogens. Volcanogens are areas along the active margins of the continent, formed at the time of completion of the margins. Two tectonic mechanisms of volcanogen formation are shown: nesting and linear. They reflect their position in the block-keyboard structure of the marginal crust and are associated with granitoid tectonic-magmatic activation. The basis of the system is the concept of the block-keyboard structure of the earth’s crust. Its initial idea is the longitudinal zoning of the marginal volcanic and folded geostructures of the Koryak-Kamchatka region. They consistently in time towards the sea build up the continent with folded-block geostructures together with a series of NE strike volcanic belts. Transverse faults form NW blocks of crust, including a sequential, from the ocean deeper into the continent, set of different-aged – “multi-colored”, parts of a series of successive conjugate longitudinal regional growth geostructures – mainly volcanic belts of the active margins of the continent. These parts are the volcanogenes of the belts as their isolated elements. Along the strike of the belts, volcanogens alternate with local tectonic geostructures such as depressions, blocks, ledges of the foundation, faults, etc., as well as folded structures of the cover and foundation. Volcanogens of the territory possess tectonic features of the orogenic development stage of the continental margin. They have tectonic elements of the system “marginal volcanic belt – local depressions and elevations of the block margin of the folded basement”. Orogenic volcanism is developed by two belts in the northwest sector of NE Asia along the northern and southern margins of the Late Cretaceous Koryak microcontinent of the Central Koryak structural-facial zone. On the southern frame of the base of the Okhotsk-Chukot volcanic belt of the northwestern sector of NE Asia are orogenic volcanic and sedimentary molasses. Orogenic volcanism is associated with important aspects of tectonics and magmatism, which created the conditions for the formation of mineralogenic taxons of gold, silver, and tin. The magmatism of tectonicmagmatic activation led to the formation of metallogenic areas of volcanogens with their adequate ore regions. The examples of the orogenic volcanic belts of the Eocene and Oligocene show the role of the geotectonic and metallogenic aspects of the block-key structure of the earth’s crust of the active continent margins.