Geological Results from Three Research Areas and their Relevance to the Nuclear Fuel Waste Management Program

Abstract

Geological data from three research areas indicates that fault-fracture systems were initiated shortly after emplacement and cooling of the plutons. These fracture systems have evolved through geologic time in response to major geologic-tectonic events, New fractures formed and existing fractures were reactivated. The effects of 'recent' geological activity appears to be largely restricted to the upper 200-300 m of the rock mass, and is constrained by the occurrence and distribution of pre-existing 'ancient' fracture systems, These results indicate that (i) stable geological environments may exist at depth, and (ii) an understanding of the 'ancient' fracture system is a basic requirement in order to develop an understanding the present day groundwater flow systems in these rocks.