The search for Elliot Lake type, uraniferous quartz-pebble conglomerates, Southern Lake Superior Region, USA

Comparisons of the Marquette Range Supergroup in Michigan south of Lake Superior with the uranium-bearing Huronian Supergroup of Ontario 250 km to the east show similarities in rock types and stratigraphic order, and stimulate the as yet unsuccessful search for uranium in the southern Lake Superior region. Radiometric dates suggest that the Marquette Range Supergroup is younger than the Huronian, and perhaps too young to contain uranium deposits of the quartz-pebble conglomerate type. However, the radiometric dates are equivocal and do not provide a maximum age for the Marquette Range Supergroup. Rock types, stratigraphic order, and environments of deposition (especially of units interpreted to be glaciogenic) provide an independent correlation approach which, although not precise, is useful. Much of the Marquette Range Supergroup was deposited prior to the proposed oxyatmoversion and the widespread deposition of iron-formations about 2,000 m.y. ago. Therefore, it has some potential for containing quartz-pebble type uranium deposits in spite of its probable younger age compared to the 2500 to 2300 m.y. old Huronian. (author). 35 refs, 3 figs, 3 tabs