Geology of the Gullbridge Copper Deposit, Newfoundland: Volcanogenic Sulfides In Cordierite–Anthophyllite Rocks

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Upadhyay, H. D., Smitheringale, W. G.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1972
• Subjects: General Earth and Planetary Sciences; Newfoundland
• Online Access: http://dx.doi.org/10.1139/e72-092; http://www.nrcresearchpress.com/doi/pdf/10.1139/e72-092

The Gullbridge copper deposit occurs in a folded and regionally metamorphosed sequence of Upper Ordovician mafic volcanic and tuffaceous rocks in the Central Mobile Belt of Newfoundland. The ore consists of chalcopyrite, pyrrhotite, and pyrite in a tabular zone of cordierite–andalusite–chlorite schist that is surrounded by cordierite–anthophyilite rock. Regional metamorphism to greenschist or amphibolite fades preceded and accompanied regional de formation that produced tight folds with a strong axial plane schistosity (S 1 ) in the host and country rocks. Contact metamoprhism related to nearby plutons superimposed the cordierite, andalusite, and anthophyllite mineral assemblages upon S 1 . This was followed by a second deformation and by chloritization of the ore zone. Finally the ore body underwent some minor mineralogical and structural modifications. From various field and laboratory evidence the sulfides, and possibly the associated magnesium alteration, are interpreted as volcanogenic. The Gullbridge deposit is similar to a number of other copper sulfide deposits in cordierite anthophyilite host rocks in North America and Scandinavia.