دورية أكاديمية
Petrology of the Porriño late-Variscan pluton from NW Iberia. A model for post-tectonic plutons in collisional settings
| العنوان: | Petrology of the Porriño late-Variscan pluton from NW Iberia. A model for post-tectonic plutons in collisional settings |
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| المؤلفون: | L. GONZÁLEZ-MENÉNDEZ, G. GALLASTEGUI, A. CUESTA, P. MONTERO, A. RUBIO-ORDÓÑEZ, J.F. MOLINA, F. BEA |
| المصدر: | Geologica Acta, Vol 15, Iss 4 (2017) |
| بيانات النشر: | Universitat de Barcelona (UB), Geociències Barcelona (Geo3BCN), Institut de Diagnosi Ambiental i Estudis de l'Aigua (IDAEA), Universitat Autònoma de Barcelona (UAB), 2017. |
| سنة النشر: | 2017 |
| المجموعة: | LCC:Science LCC:Geology |
| مصطلحات موضوعية: | Post-orogenic magmatism, Variscan orogen, Postectonic granites, Monzogranites, Enclaves, Science, Geology, QE1-996.5 |
| الوصف: | The Variscan orogen of NW Iberia contains abundant syn- and post-tectonic granitoids. The post-tectonic granitoids are metaluminous to slightly peraluminous, I-type granites, monzogranites ± granodiorites ± tonalites. The Porriño pluton studied here is a representative example. It consists of two units: i) a pink-red, peraluminous, biotite granite and ii) a gray, metaluminous to peraluminous, biotite (± amphibole ± titanite) monzogranite, including maficintermediate enclaves. SHRIMP U-Pb dating yielded 290-295Ma ages for all the units. The mineralogy and geochemistry show that the pink-red granite has features of I- and A-type granites, whereas the gray monzogranite and enclaves are I-types. Sr isotopes show scattered values for the pink-red granite (87Sr/86Sr295Ma ≈ 0.702-0.710) and uniform values for the gray monzogranite and enclaves (87Sr/86Sr295Ma≈ 0.705-0.706). Geochemical results indicate a peritectic entrainment of clinopyroxene + orthopyroxene ± Ca-plagioclase ± ilmenite ± garnet, and minor accessory phases (± zircon ± titanite ± apatite) into a melt similar to the leucocratic gray monzogranite. A mafic-intermediate source is proposed for the gray monzogranite and its enclaves. Restitic protoliths generated granitic melts with A-type features such as the pink-red granite. The I-type nature of many post-tectonic granitoids could be explained by the previous extraction of S-type syn-tectonic granites that left restites and less fertile rocks. Late orogenic new melting affected the previously unmelted and more mafic lithologies of the lower-middle crust, and gave rise to I-type granitoids. Repeated melting events affecting such lithologies and previous restites could have generated granitic melts with A-type features. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1696-5728 |
| Relation: | https://revistes.ub.edu/index.php/GEOACTA/article/view/17607; https://doaj.org/toc/1696-5728 |
| URL الوصول: | https://doaj.org/article/833b1766d1634fbeb94c1d5991d3f49c |
| رقم الأكسشن: | edsdoj.833b1766d1634fbeb94c1d5991d3f49c |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 16965728 |
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