Types, abundances and distribution of kimberlite indicator minerals in alluvial sediments, Wawa-Kinniwabi Lake area, Northeastern Ontario: implications for the presence of diamond-bearing kimberlite

In response to the discovery of diamonds within modern alluvium in the glac iated area of Wawa Ontario, Canada, the Ontario Geological Survey undertook st regional program of surficial mapping and modern alluvial sediment samp ling to assess the potential of the area for diamond-bearing kimberlite. Fi ve varieties of kimberlite-derived indicator minerals were recovered and th e composition of three varieties was evaluated, resulting in the identifica tion of G10 Cr-pyrope garnet, inclusion field chromite and Mg-ilmenite. The distribution of indicator minerals was examined in the context of the glac ial and bedrock geology. Glacial dispersal from non-kimberlitic marker unit s is restricted (commonly less than 200 m) and many kimberlite indicator mi nerals were recovered from samples collected close to cross-cutting NE-SW a nd NW-SE faults and a strong NE-SW trend in the bedrock associated with the Kapuskasing Structural Zone. From this, several potential exploration targ ets for diamond-bearing kimberlite are defined. (C) 1998 Elsevier Science B .V. AU rights reserved.