On the Origin of the Amphibolites of the Laurentian Area of Canada
| Autor: | Frank D. Adams |
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| Rok vydání: | 1909 |
| Předmět: | |
| Zdroj: | The Journal of Geology. 17:1-18 |
| ISSN: | 1537-5269 0022-1376 |
| DOI: | 10.1086/621582 |
| Popis: | In a paper which appeared in the last number of this Journal an account was given of the development of the Grenville series in a great tract of the Laurentian Protaxis, some 4,200 square miles in extent, situated in the eastern part of the Province of Ontario, a study of which has recently been completed for the Geological Survey of Canada by Dr. A. E. Barlow and the writer. In this tract the Grenville series is not only of great areal extent but is of enormous thickness. About one-half of this thickness consists of limestone while the remainder consists of gneisses of sedimentary origin (paragneiss), with occasional quartzites and great bodies of amphibolite. This series is invaded by enormous bathyliths of gneissic granite and while in the southeastern portion of the area toward the margin of the Protaxis, the sedimentary series is comparatively free from igneous intrusions, toward the northwest the granite in ever increasing amount arches up the sedimentary series and wells up through it, in places disintegrating it into a breccia composed of shreds and patches of the invaded rock scattered through the invading granite, until eventually connected areas of the sedimentary series disappear entirely and over hundreds of square miles the. granite and granite-gneiss alone are seen, holding, however, in |
| Databáze: | OpenAIRE |
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