Toward an integrated geologic, geochemical, and structural model for formation of the MacLellan Au-Ag and related mineral deposits, Lynn Lake, Manitoba

摘要

The MacLellan deposit and related Au-Ag occurrences reside in the northern portion of the Lynn Lake greenstone belt, Manitoba. All occurrences within the study area contain the same lithologies, alteration styles, and were formed by similar processes. The Nisku Deposit, Main and Dot Zones contain the most abundant Au-Ag mineralization and are characterized by increased arsenopyrite, galena, and sphalerite relative to other zones. These deposits occur at intersections between D4 north-northeast striking brittle fault zones and D2 ≈ 045° striking ductile shear zones. The differences in mineralization styles between individual zones result from the presence or absence of these intersecting D2-D4 structures. Gold and silver mineralization is the result of hydrothermal fluid infiltration along zones of high strain that formed during D2 and D4 deformation events. Amphibole-plagioclase schist has been altered by biotite ± quartz ± sulphide mineral alteration (D2) and Cr-clinochlore + carbonate ± hornblende + quartz alteration (D4).