A revised Ordovician age for the Miranda do Douro orthogneiss, Portugal. Zircon U-Pb ion-microprobe and LA-ICPMS dating
| Autor: | F. BEA, P. MONTERO, C. TALAVERA, T. ZINGER |
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| Jazyk: | angličtina |
| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Geologica Acta, Vol 4, Iss 3 (2006) |
| Druh dokumentu: | article |
| ISSN: | 00000035 1696-5728 |
| DOI: | 10.1344/105.000000353 |
| Popis: | The Miranda do Douro orthogneiss was believed to be the oldest magmatic rock of the Central Iberian Zone, on the base of a U-Pb discordia upper intercept of 618 ± 9 Ma. Nevertheless, new ion-microprobe and LA-ICPMS U-Pb zircon dating revealed that the crystallization age was 483 ± 3 Ma. The orthogneiss also contains a 605 ± 13 Ma zircon population that indicates that the source-rock for the Ordovician magma was Pan-African. Moreover, a few ~3.17 Ga zircon grains were also recorded. These grains are the oldest found so far in Iberia, and its occurrence would suggest the involvement of an Archean crust in the Pan-African orogeny. |
| Databáze: | Directory of Open Access Journals |
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