Chrysotile mines: a window on the structure of the northern Appalachians.

Structures and patterns in the Thetford mine harzburgite, Quebec, are reviewed using the geology of LAB chrysotile orebodies as a model. Structural aspects include north and north-east-striking faults and bendings in granite dykes which created tension zones favourable to chrysotile development in the neighbouring harzburgite. Serpentinisation patterns include primary pervasive mass serpentinisation and secondary complete serpentinisation which was superimposed on the primary event, affecting a few centimetres on each side of tension cracks. Cracks have developed in stockworks which can be characterised by the width and the orientation of each chrysotile vein. The north-striking faults extend outside the chrysotile belt in other structural zones of the Appalachians where they appear as important lineaments. Thetford mine is the oldest mining camp in Canada.
Structures and patterns in the Thetford mine harzburgite, Quebec, are reviewed using the geology of LAB chrysotile orebodies as a model. Structural aspects include north and north-east-striking faults and bendings in granite dykes which created tension zones favourable to chrysotile development in the neighbouring harzburgite. Serpentinisation patterns include primary pervasive mass serpentinisation and secondary complete serpentinisation which was superimposed on the primary event, affecting a few centimetres on each side of tension cracks. Cracks have developed in stockworks which can be characterised by the width and the orientation of each chrysotile vein. The north-striking faults extend outside the chrysotile belt in other structural zones of the Appalachians where they appear as important lineaments. Thetford mine is the oldest mining camp in Canada.