The Origin and Emplacement of the Rock Units in Mule Creek, Northwestern British Columbia

Abstract

In 1982 field work was carried out in northwestern British Columbia for Noranda Exploration Company, Ltd. Here a sequence of porphyritic and vesicular volcanic flows containing interbedded gypsum was discovered. Finely disseminated sulphide was found within this gypsum. Whether economically important quantities of copper-bearing sulphides exist here is unknown at this time.

Microscopic study of thin sections, and X-Ray diffraction spectra, show the mineralogy to be representative of greenschist facies metamorphism. Sulphur isotope data: dS34 = +11.7 for gypsum and +11.3 for barite are interpreted as indicating a middle to late Permian age of these sulphates.

The Denali fault system is a dynamic fault zone active since Cretaceous-Jurassic time and presumed still active. This system is responsible for assembling the series of originally temporally and spatially separated units observed today in Mule Creek. The pulsing of this system through time has produced extensive brecciation and shearing over the whole study area.

Keywords: Pages: 65 Supervisor: G. Clint Milligan