Geological Mapping of the Needleboy Lake – Six Mile Lake Area, Northeastern Minnesota: a Summary of Volcanogenic Massive Sulfide Potential

Abstract

The Needleboy Lake and Six Mile Lake areas has focused on evaluating the stratigraphic succession, hydrothermal alteration, and synvolcanic and post-volcanic structures in an effort to better understand the VHMS potential in this region of the Lower Ely Greenstone. Field mapping in the Needleboy Lake area (performed during August, 2001) investigated all outcrops within a 100 to 200 meter perimeter of the Lake. A north-south section was also completed from the north-central shoreline of Five Mile Lake to the western shoreline of Needleboy Lake. Field mapping in the vicinity of Six Mile Lake (performed August-September, 2002) included three detailed north-south traverses (Fig. 4). Traverse 1 extended from the northwestern shoreline of Needleboy Lake to the western shoreline of Six Mile Lake. Traverse 2 extended from the northeastern shoreline of Needleboy Lake to approximately 200 meters north of Six Mile Lake. Traverse 3 extended from the southeastern part of Needleboy Lake to approximately 500 meters northeast of Six Mile Lake. In addition, all outcrops occurring along roads in the study area were investigated.