Composición komatiítica de las hornblenditas del Macizo del Montnegre (Sierra Litoral Catalana, NE de la Península Ibérica)
Olivine hornblendites represent the most remarkable petrological type from the Montnegre massif. Its ultramafic composition and its close association with a hornblende gabbro intrusion suggest, at first, a cumulative origin from a hydrated basaltic magma. However, major element composition, coincide...
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universidad de Huelva (UHU) |
| Repositorio: | Arias Montano. Repositorio Institucional de la Universidad de Huelva |
| Idioma: | español |
| OAI Identifier: | oai:ariasmontano.uhu.es:10272/13600 |
| Acceso en línea: | http://hdl.handle.net/10272/13600 |
| Access Level: | acceso abierto |
| Palabra clave: | Hornblendite Komatiite Cortlandtite Hercynian Montnegre massif Hornblendita Komatiita Cortlandtita Herciniano Macizo del Montnegre |
| Sumario: | Olivine hornblendites represent the most remarkable petrological type from the Montnegre massif. Its ultramafic composition and its close association with a hornblende gabbro intrusion suggest, at first, a cumulative origin from a hydrated basaltic magma. However, major element composition, coincident with komatiites and –very roughly– with the komatiitic trend, suggests the possibility of their origin by fractional crystallization processes from an ultramafic magma. The high MgO contents of hornblendites (up to 25 wt.%) would require an elevated partial melting degree of the mantle. Unlike komatiitic magma, hydrated ultramafic magma can be produced at significantly lower temperatures after H2O (or other volatile) influx, as suggested for the "Alaskan-type" intrusions. On the other hand, the obvious subalkaline affinity of olivine hornblendites and hornblende gabbros from the Montnegre massif (showing high amounts of normative hyperstene) compositionally distinguishs them from Cortlandt ultramafic complexes, of alkaline affinity |
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