Economic Geology; May 2005; v. 100; no. 3;
p. 577-582; DOI: 10.2113/100.3.577
© 2005 Society of Economic Geologists
Scientific Communications |
STRUCTURAL CONTROLS ON THE ARCHEAN TROILUS GOLD-COPPER DEPOSIT, QUEBEC, CANADA
S. Goodman
,
A. E. Williams-Jones and
P. Carles
McGill University, Department of Earth and Planetary Sciences, Montreal H3A
2A7, Canada
Corresponding author: e-mail, sgoodman{at}srk.com
The Troilus gold-copper deposit is a low-grade, high-tonnage resource, hosted
in Archean calc-alkaline intrusive rocks, in the Superior province of Quebec. It
is best known for being one of the few Archean analogues of a porphyry Cu-Au
deposit, an interpretation with significant implications for both mineral
exploration and theories of Archean plate tectonics. Recent research presented
here has called into question the prevalent genetic model and proposes instead a
two-stage history of mineralization controlled by contrasting structural regimes
developed as part of an orogen. Disseminated gold-copper mineralization and
associated potassic alteration occur in a deformation corridor between two
felsic dikes, emplaced prior to the peak of regional metamorphism. Postpeak
metamorphic, high strain sericitic zones with silicified envelopes host quartz
veins and a second phase of gold. The present size, grade, and disposition of
the orebody is the result of the superposition of these two events, an
interpretation that impacts on the genetic model as well as exploration,
exploitation, and grade control.
Copyright © 2009 by Society of Economic Geologists