Tectonodynamics of fluid-conducting structural elements and migration of radionuclides in massifs of crystalline rocks

Abstract

The principal aspects of reconstruction of conditions and paths of fluid migration in massifs of crystalline rocks are considered. The spatiotemporal relationships between stress fields, brittle failure, and migration of radionuclides are discussed. The main attention is focused on the staged character of tectonic events, fluid circulation conditions, and the sequence of uranium mineral formation as determined with structural, geological, tectonophysical, petrophysical, petrographic, mineralogical and geochemical, microstructural, microthermometric, and radiographic methods. As is exemplified in uranium deposits and massifs of silicic igneous rocks, the comprehensive consideration of the tectonodynamics of fluid-conducting structural elements and radionuclide migration is necessary for providing insights into the localization and redistribution of uranium, the PT conditions of uranium ore formation, and the forecast for long-term safety of disposal of radioactive wastes in crystalline rocks.

Fault tectonics, neotectonic stresses, and hidden uranium mineralization in the area adjacent to the Strel’tsovka Caldera

“…The phases of reactivation of structure forming and hydrothermal processes in fault zones are reflected in distinguishing features of dynamometamorphism and relationships between metasomatic alterations (Andreeva et al, 2010) from the early high temperature feldspatization and greisenization to the late low temperature hydro mica, carbonate, and argillic alterations. The intervals of hydrothermal activity and peak permeability of var iously oriented fault zones are confirmed by the orien tation of fluid inclusion planes and properties of these inclusions (Petrov et al, 2008a), which were studied using the technique described by Lespinasse and Pecher (1986) and developed further in Lespinasse et al (2005). As follows from the highest inflows of water in the process of drilling, the intersections of north northeast to near meridional and NE-SW faults are currently most hydraulically active.…”

The Antei uranium deposit: A natural analogue of an SNF repository and an underground geodynamic laboratory in granite

“…Their interaction inevitably leads to a change in the filtration properties and sorption capacity of faults and the rock massif as a whole. The changed sorption capacity of mineral aggregates in fractures and nearby causes a shift in conditions of radionuclide transport and replacement of one mechanism of transportation by another (Petrov et al, 2008). As a result, faults and related zones of dynamic effect may alternately serve as either conduits or barriers on the path of fluid migration and radionuclide transport, i.e., fulfill a combined function of conduits and hindering barriers.…”