Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan
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.
Citation Information
Publication Year | 1981 |
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Title | Sm-Nd systematics of a tonalitic augen gneiss and its constituent minerals from northern Michigan |
DOI | 10.1016/0016-7037(81)90148-4 |
Authors | K. Futa |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geochimica et Cosmochimica Acta |
Index ID | 70012018 |
Record Source | USGS Publications Warehouse |