The Wawa diamond enigma

Recognition of the diamond potential of the Wawa subprovince was initially determined from regional data using a kimberlite model. The world's largest stable Precambrian craton, the Superior Province, is considered to be favourable for the emplacement of diamondiferous kimberlite. The Wawa area is located near the intersection of intra-craton structures visible in the regional magnetic data. The Enigma project is located north of the town of Wawa in northern Ontario. From field evidence and background research, it became obvious that in the Wawa area there were at least two potentially diamond-hosting events, Archean lamprophyric volcaniclastics and Proterozoic kimberlites. The host lamprophyric rock does not contain the classical KIM signatures. However, to complicate the Enigma, stream sediment samples within 200 m of the diamond-bearing lamprophyre produced a typical suite of kimberlite indicator minerals. The micro- and macro-diamond content of the Wawa lamprophyric volcaniclastic rocks Is typically 0.2 ct/t to I ct/t, although it can be higher locally. The economic diamond potential of these Archean dykes, sills and irregular lamprophyre bodies is still under-explored (Kaminsky, 2002 unpubl.). Oasis Diamond Exploration is currently exploring the area using geophysical, geochemical, and geological data.