Abstract
It is probably more important to locate and design a Swedish radwaste repository in relation to cryptic fracture zones that dip gently than to the more obvious fractures zones with steep dips. This is because shallow, gently dipping fracture zones exert the greater control on the lateral flow of groundwater and segment the rock mass into layers with different mechanics. But comparatively little is known about gently dipping fracture zones and their origins. One of the greatest problems is how deep such zones were destressed during melting of the Quaternary ice sheets. Current exploration practise is washing away the soft fracture fillings that would allow study of this problem.