Abstract

The Agassiz metallotect is a 70-km-long zone of coincident magnetic and electromagnetic geophysical anomalies that correspond to a stratigraphic succession characterized by picritic basalt; oxide, silicate, and sulfide facies iron-formation; and clastic sedimentary rocks. En echelon shear zones with accompanying carbonatization, silicification, and chloritization occur throughout the stratigraphy. The stratigraphic sequence that characterizes the Agassiz metallotect hosts five known gold deposits including the MacLellan Au-Ag deposit that contains 1.2 million metric tons grading 6.51 g/metric ton Au and 18.89 g/metric ton Ag.Samples were collected from altered picritic basalt hosting the MacLellan deposit and unaltered picritic basalt. Both suites of samples were analyzed for 27 major and trace elements. A stepwise discriminant function analysis identified Au, Sb, Ba, Zn, Ni, Cr, Na 2 O, and Fe 2 O 3total from the original 27 chemical variables as the optimum discriminating variables for distinguishing altered from unaltered picritic basalt. The derived discriminant function was applied to rock geochemical data acquired from picritic basalt samples collected during a regional geochemical survey of the Agassiz metallotect. Five zones of multivariate anomalies were identified using this technique. The samples that characterize these multivariate anomalies are interpreted to have geochemical alteration characteristics similar to the wall rocks at the MacLellan deposit, and accordingly, represent exploration targets.

First Page Preview

First page PDF preview
You do not currently have access to this article.