دورية أكاديمية
Magnetic susceptibility of Variscan granite-types of the Spanish Central System and the redox state of magma.
| العنوان: | Magnetic susceptibility of Variscan granite-types of the Spanish Central System and the redox state of magma. |
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| المؤلفون: | Villaseca, C., Ruiz-Martínez, V.C., Pérez-Soba, C. |
| المصدر: | Geologica Acta; 2017: Vol.: 15 Núm.: 4. Special Issue: Granites and Related Rocks: a tribute to Guillermo Corretgé; p. 379-394 |
| حالة النشر: | published |
| بيانات النشر: | Universitat de Barcelona, 2017. |
| سنة النشر: | 2017 |
| مصطلحات موضوعية: | Magnetic susceptibility, Granite type, Biotite chemistry, Oxygen fugacity |
| الوصف: | Magnetic susceptibility (MS) has been measured in Variscan granites from central Spain. They yield values in the order of 15 to 180µSI units for S- and I-type granites, indicating that both types belong to the ilmenite series. Only samples from magnetite-bearing leucogranites from the I-type La Pedriza massif show high MS values, in the order of 500-1400µSI, reflecting the presence of this ferromagnetic mineral. Mineral chemistry of magmatic Fe-rich minerals (mainly biotite) suggests similar oxidation values for both granite types. MS values change in highly fractionated granites accordingly either with the presence of rare new Fe-oxide phases (some I-type leucogranites) or with the marked modal amount decrease of Fe-rich minerals (I- and S-type leucogranites). The redox state in highly fractionated granite melts is mostly controlled by magmatic processes that modify redox conditions inherited from the source region. Thus, the occurrence of magnetite or ilmenite in granites is primarily controlled by the oxidation state of the source material but also by the differentiation degree of the granite melt. The presence of magnetite in some Variscan I-type leucogranites might be a consequence of crystal fractionation processes in a more limited mafic mineral assemblage than in S-type granite melts. |
| نوع الوثيقة: | article |
| وصف الملف: | text/html |
| اللغة: | English |
| تدمد: | 1696-5728 1695-6133 |
| العلاقة: | https://www.raco.cat/index.php/GeologicaActa/article/view/330805/421688Test |
| الوصول الحر: | https://www.raco.cat/index.php/GeologicaActa/article/view/330805Test |
| رقم الانضمام: | edsrac.330805 |
| قاعدة البيانات: | RACO (Revistes Catalanes amb Accés Obert) |
Full Text Finder | تدمد: | 16965728 16956133 |
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