Gold mineralization associated with archean stratabound sulphides in the Cheminis deposit near Larder Lake, Ontario

CIM Bulletin, Vol. 80, No. 902, 1987

R.J.McH. CLARK, Elder Resources Limited, Ottawa, Ontario, and R. BONNAR B.P. Canada Inc. Calgary, Alberta

The Cheminis gold mineralization zone is approximately 6.5 km west of the Ken Addison Mine along the Larder Lake Shear Zone, in the southern part of the Abitibi Greenstone Belt. The zone is very similar in appearance to the flow ore at the Kerr Addison Mine and occurs at the same stratigraphic position. Drilling has demonstrated that the gold mineralization at Cheminis persists to a depth of over 3000 ft. The mineralization is hosted by a pyritic, tuffaceous sediment which occurs within a sequence of volcanics and sediments which have been pervasively carbonatized. The gold is largely enclosed within pyrite grains and the amount of gold in the layers of pyrite increases in the layers closest to a graphitic fault zone. It is suggested that the gold mineralization may be primarily related to the syngenetic sulphide concentrations formed during fumarolic activity on the seafloor along the Larder Lake Shear Zone. At a later stage a hydrothermal event associated with alkalic volcanism may have resulted in regional carbonatization and further concentration of the gold in the vicinity of fault zones.
Keywords: Mineralization, Gold deposits, Cheminis deposit, Larder Lake, Sulphides.