Late Cretaceous Granites Of The Selennyakh Ridge (Verkhoyansk-Kolyma Orogenic Area)

Authors

  • Vera A. Trunilina

Abstract

The article considers the distinctive features of the composition of the Late Cretaceous granites of the Selennyakh Ridge with different-scale rare-earth mineralization. The granite massifs are localized in the west of the Selennyakh synclinorium of the Verkhoyansk-Kolyma orogenic area and in the adjacent part of Tas-Kayakhtakh anticlinorium. The isotopic age of granites is 85 to 94 million years. It is shown that the granites of all of the studied massifs belong to A-type postorogenic geodynamic setting. The parent melts were generated in the deep metamorphised Paleoproterozoic substrates of the lower crust under the influence of heat and fluids, produced by deep mantle magmae. Granites are characterized by high differentiation and alkalinity; combination of high-temperature minerals typical of basic rock and low-temperature, granitic, rock-forming, and accessory minerals; an important role of chlorine in crystallization. It is assumed that the considered territory contains buried hearths of basic melts, the activation of which in the Late Cretaceous period caused the re-melting of crustal substrates. Rare-earth mineralization occurred during the crystallization of the melt, formed in the lower parts of the granite hearth under the influence of an intensive deep fluid flow.

Published

2020-10-01

Issue

Section

Articles