Old K–Ar Mineral Ages from the Grenville Province, Ontario
| Autor: | J. B. Hartung, M. R. Dence, J. F. Sutter |
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| Rok vydání: | 1971 |
| Předmět: | |
| Zdroj: | Canadian Journal of Earth Sciences. 8:1495-1498 |
| ISSN: | 1480-3313 0008-4077 |
| Popis: | Hornblende-rich concentrates from quartz–feldspar gneisses of the Grenville Province near Brent Ontario, have yielded K–Ar apparent ages of 1570 to 1480 ± 80 m.y., while coexisting biotite- and feldspar-rich separates give 'normal' Grenville K–Ar ages near 900 ± 40 m.y. Comparison with the nearest Rb–Sr isochron dates suggests that the indicated hornblende K–Ar age represents a minimum age for time of crystallization of the gneisses in the Brent area and that the younger ages for minerals with lower blocking temperatures indicate a later thermal event in the metamorphic history of the Grenville Province. |
| Databáze: | OpenAIRE |
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