Abstract

Chemical compositions of Archaean volcanic rocks in the Superior province of the Canadian shield have been determined from 261 new analyses from 10 volcanic belts. The analyses are compared with those of the various volcanic associations. This comparison shows that the volcanic rocks of all belts belong to the basalt andesite rhyolite association typical of continental orogenic belts or island are systems. A primitive continent with continental rocks must, therefore, have existed in early Archaean time.The Keewatin lava sequences in the various belts are remnants of a great volcanic sequence that covered the southern half of the Superior province of the Canadian shield.

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