| Abstract: | The Sm-Nd isotopic system of a tonalitic augen gneiss and its constituent minerals from northern Michigan was disturbed during metamorphism. Sm-Nd zircon ages are lower than the wholerock Sm-Nd model age. However, closely associated pairs of minerals (for example, sphene and biotite or apatite and plagioclase) retain their apparent metamorphic ages. The Sm-Nd model age for the tonalitic augen gneiss of 3919 ?? 30myr, appears to reflect open system behavior during metamorphism. A mineralogically different gneiss from the same location has a Sm-Nd model age of 3520 ?? 70 myr. The two whole rocks differ in their Sm-Nd and Rb-Sr systematics and in their chondrite-normalized rare earth element (REE) patterns. The whole-rock-normalized mineral REE patterns show the contribution of the major and trace minerals to the REE content of the whole rock. The trace minerals contain a significant amount of the total REE. ?? 1981. |
| Genre: | Article |
| ProdID: | 70012018 |
| Citation Author: | Futa, K. |
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| Citation End Page: | 1249 |
| Citation Issue: | 7 |
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| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
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| Citation Number Of Pages: | 5 |
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| Citation Search Results Text: | Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan; 1981; Article; Journal; Geochimica et Cosmochimica Acta; Futa, K. |
| Citation Start Page: | 1245 |
| Citation Volume: | 45 |
| Citation Year: | 1981 |
| Type: | citation/reference |
| Text: | Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan; 1981; Article; Journal; Geochimica et Cosmochimica Acta; Futa, K. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Thu, 1 Jan 1981 00:00 -0600 |
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