Classification of quartz veins in turbidite, hosted gold deposits, greenschist fades, eastern Nova Scotia

CIM Bulletin, Vol. 80, No. 898, 1987

S.J. HAYNES, Brock University, St. Catharines, Ontario

This paper documents the characteristics of the different quartz veins, and their relation to gold, in the turbiditic Meguma domain of eastern Nova Scotia. Eleven different types have been distinguished in the greenschist fades on the basis of form, internal structure, mineralogy, wall rock alteration and crosscut-ting relationships to each other and to regional structures. Gold is present as rare visible disseminations in host rock slates and in ore-grade, early-formed veins, that pre-date the formation of upright Acadian folds and intrusions of Devonian granitoids. Four vein types pre-date Acadian folding. Five gold-deficient vein types are associated with Acadian folding (syn-deformation); whereas two gold-deficient vein types clearly post-date this deformational event. Previously unreported, wall rock alteration is associated with early crosscutting and semi-concordant auriferous veins. In contrast, early stratiform veins are devoid of wall rock alteration. It is suggested that the auriferous vein arrays formed as submarine exhalitive systems over synsedimentary tensional faults and that the Meguma domain may represent the opening of a basin similar to the modem Guaymas rift.

Mots Clés: Mineral exploration, Gold, Greenschist facies, Quartz veins, Meguma group, Mineralogy.