| 释义 |
Keewatin Geol.|kiːˈweɪtɪn|
The name of a district in the Northwest Territories, Canada, used attrib. and absol. to denote the oldest division of the Archæan in North America and rocks representing it, found in the Canadian Shield region.
1886A. C. Lawson in Ann. Rep. Geol. Survey Canada 1885 I. 14cc, The most appropriate name for the series that suggests itself to me is ‘Keewatin’, the Indian name for the North-west, or the North-west wind, which has been applied to the district within which the rocks occur. Ibid. 19cc, The contact of the Laurentian gneiss and the Keewatin schists. 1925Bull. Geol. Soc. Amer. XXXVI. 363 The Coutchiching beds pass down under the Keewatin. 1927Jrnl. Geol. XXXV. 143 At present the general use of the term Keewatin in the United States and Canada is as the name of the oldest rock series of the region. Ibid., The view that the Keewatin rocks are the oldest in Canada is moreover inconsistent with much recent geological work. 1970Dorr & Eschman Geol Michigan iv. 39/1 Nearly 3·5 billion years ago, during Keewatin time, streams from bordering highlands deposited sediments and lavas poured out on the surface of the earth in what is now the Upper Peninsula of Michigan. 1972L. W. Mintz Hist. Geol. xiii. 388 Keewatin rocks, like all other very old sediments, appear to be oceanic in origin and consist chiefly of metamorphosed lavas and turbidites. |