Courageous Lake: GEOLOGY
Regional Geology
The Courageous-Matthews Lakes belt is characterized by a series of north to northwest trending Archean metavolcanic and metasedimentary rocks that form a portion of the Slave Structural Province. These rocks are within the Yellowknife Supergroup and are locally referred to as the Courageous Lake Greenstone Belt ("CLGB"). The CLGB is approximately 60 kilometers long, with a maximum east-west width of 5.5 kilometers. The rocks within the CLGB have been metamorphosed to greenschist facies, and have undergone at least two major deformational events. The Mackey Lake and Courageous Lake stocks, which are large granitic intrusions, bound the belt on the east and west.
The CLGB forms a steeply dipping homoclinal sequence of metavolcanic and metasediments that are younger towards the east. Two distinct volcanic cycles have been recognized within the CLGB. The basal cycle is characterized by mafic to intermediate flow and pyroclastic rocks, which for the most part have been assimilated by the Courageous Lake Batholith. The second cycle contains mafic to felsic flow and pyroclastic rocks that are spatially related with felsic intrustives. The second cycle of volcanism is conformably overlain by a thick sequence of metasedimentary rocks that are locally known as the Yellowknife Group Sediments ("YGS"). The dominant post YGS lithology consists of large granodiorite to diorite plutons that bound the Courageous Lake deposit along its east and west flanks. Post dating the granite and greenstone rocks in the area are late Protozoic gabbroic and diabase dikes which trend north to northeast or east-west.
Property Geology
The Courageous Lake property consists of a sequence of northerly trending, steeply dipping metasedimentary and metavolcanic rocks, with tops to the east. All of the currently recognized gold occurrences on the property are located within or near the top of the second cycle of volcanism of the CLGB. The thickest part of this second volcanic cycle is located north of Matthews Lake where drag folding has duplicated the section. Generally, the units that make up the second volcanic cycle are about 2 kilometers thick and have been subdivided into 8 distinct mappable units.
These units are a mafic volcanic unit, which forms the basal member of the second volcanic cycle; a lower felsic volcanic unit which is overlying the mafic volcanic rock units; a carbonate unit, which is a distinctive alteration of a felsic volcaniclastic unit; gully sedimentary rocks of interbedded argillite and greywacke beds; upper felsic volcanic unit, which overlies the gully sedimentary rocks and is comprised of rhyolite flows, felsic pyroclastic fragmental rocks and volcaniclastic debris flows; a mineral zone, which is a distinct subdivision of the upper felsic volcanic unit; and transitional sedimentary units, which are composed of clastic felsic ash and lapilli beds.
Both the main Tundra and Carbonate zones within the Courageous Lake property strike north-south and have a near vertical dip component. The zones are characterized by moderate to intense shearing, sericite-carbonate alteration, and quartz veining. These mineralized zones are very persistent along strike and down dip. The continuity of gold mineralization has been demonstrated to be at least 800 meters along strike based upon previous drilling results. Within the area that has been tested by drilling, the continuity of gold mineralization is at least 100 meters in a down dip direction. The limits of gold mineralization have not been fully tested and the deposit remains open along strike and down dip.
