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TO THE QUESTION OF THE BASITE STRUCTURE AND AGE OF A TRAP FORMATION IN THE BASIN OF THE VILYUY MID-CHANNEL – THE MARKH HEADSTREAM

V. I. Tikhonenko, A. Yu. Turkin

Siberian Research Institute of Geology, Geophysics and Mineral Resources, Novosibirsk, Russia

The structural position of basite manifestations of a trap formation is described. The data on uranium-lead dating of zircon from intrusions of dolerites and hornfelses based on basalt tuffs, as well as the content of petrogenic components and rare-earth elements in dolerites and pyroxene hornfelses are given. Clinopyroxenes of hornfelses clearly differ from rock-forming clinopyroxenes of dolerites, which is confirmed by mineralogical-crystallochemical studies. It is established that volcanic activity in the region began in the second half of Carboniferous 309–306 and continued in the early – 298–273, middle – 267–265 and up to the end of Permian – 261–256 Ma. The conclusions are confirmed by the relative age of dolerite bodies, differences in the contents of petrogenic components and rare-earth elements, and are consistent with previous years of research on spore-pollen complexes of Early and Late Permian from terrigenous sediments, stratified with basalt tuffs.

Keywords: structures, geochronology, zircon, volcanism, Siberian Platform, Carboniferous, Permian.

DOI 10.20403/2078-0575-2019-4-3-16