Isotopic character of Cambro‐Ordovician plutonism, southern Victoria Land, Antarctica
| Autor: | Alan Cooper, Andrew Allibone, David L. Parkinson, Simon C. Cox |
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| Rok vydání: | 2000 |
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| Zdroj: | New Zealand Journal of Geology and Geophysics. 43:501-520 |
| ISSN: | 1175-8791 0028-8306 |
| Popis: | Previous mapping of granitoid rocks in the Dry Valleys area of southern Victoria Land, Antarctica, identified the calc‐alkaline (DV1a), adakitic (DV1b), and monzonitic (DV2) suites. A fourth older suite comprising alkaline gabbro, syenite, and A‐type granite occurs in the Mt Dromedary area c. 80 km to the south. U‐Pb zircon dating of Bonney Pluton, the largest calc‐alkaline DV1a intrusion, indicates emplacement of this regional‐scale body at 505 ± 2 Ma. Pb‐loss and inherited zircon were common to Bonney Pluton analyses of this study. U‐Pb dating of monazite from Valhalla Pluton, a principal DV1b suite adakitic intrusion, indicates emplacement at 488 ± 2 Ma. The Bonney Pluton age constrains the peak of calc‐alkaline plutonism at 505 Ma and the Valhalla Pluton age records the major pulse of adakitic plutonism that is inferred to mark the final stages of subduction c. 490 Ma along this section of the East Antarctic margin. Nd and Sr isotope data for the calc‐alkaline DV1a suite and adakitic DV1b sui... |
| Databáze: | OpenAIRE |
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