Mineral deposits associated with granitoid intrusions and related subvolcanic stocks in New Brunswick and their relationship to Appalachian tectonic evolution

CIM Bulletin, Vol. 75, No. 842, 1982

A.A. RUITENBERG and LR. FYFFE, Geological Surveys Branch, New Brunswick Department of Natural Resources, Fredericton, N.B.

This paper compares several distinct types of mineral deposits associated with different families of granitoid rocks in the New Brunswick Appalachians. Porphyry copper deposits are assodated with late-stage differentiates of Lower to Middle Devonian I-type igneous complexes. Contact metasomatic deposits were formed where these plutons intrude carbonate rocks and they gave rise to vein deposits in fracture zones near wrench faults. The I-type granitoids were emplaced mainly in areas of thin continental crust and locally along prominent faults in areas of thick continental crust.In contrast, tin-tungsten-molybdenum-bearing greisen deposits and skarns, and antimony-bearing quartz veins are associated with predominantly S-type granitoid complexes ranging in age from Middle Devonian to early Carboniferous. The mineral deposits occur within or along the contacts of very fractionated (specialized) late phases of these intrusive complexes, which are characterized by high K2O/Na2O, Rb/Sr and Rb/Ba, and low Fe, Mg, Zr and Ti contents. These specialized granitoids are in a large wrench fault zone that cuts across thick continental crust in southwestern and central New Brunswick.
Keywords: Geology, Ore deposits, Intrusions, Granitoid intrusions, Subvolcanic stocks, Tectonics, Appalachians, Porphyry copper deposits, Contact metasomatic deposits, Vein deposits, Copper, Nickel, Tin, Tungsten, Molybdenum, Antimo, Exploration, Petrochemistry, Pokiok Batholith, Burnt Hill Intrusion, St. George Batholith, Variation diagrams.