Petrology of Matthew and Hunter volcanoes, South New Hebrides island arc (Southwest Pacific)
| Autor: | Michel Monzier, Patrick Maillet, Christian Lefevre |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1986 |
| Předmět: |
Peridotite
geography Fractional crystallization (geology) geography.geographical_feature_category Subduction biology Mantle wedge Andesites ANALYSE CHIMIQUE Geochemistry New Hebrides PETROGRAPHIE INCLUSION biology.organism_classification MODELISATION MAGMATISME CALCOALCALIN Volcanic rock ELEMENT EN TRACE Geophysics Geochemistry and Petrology GEOCHIMIE Island arc ROCHE VOLCANIQUE Geology Seismology |
| Popis: | Matthew and Hunter, the two southernmost active volcanoes of the New Hebrides island arc (southwest Pacific) differ markedly from the other (mainly tholeitic) Quaternary volcanoes of this arc. Geodynamically related to the New Hebrides subduction zone, they also lie close to the southern limb of the active expanding ridge of the North Fiji Basin. Both volcanoes are made up of acid, medium-K, calcalkaline orogenic andesites, containing a variety of inclusions (pyroxene- and gabbroic cumulates, as well as doleritic cognate inclusions). This paper presents the first systematic petrographic and chemical study of these volcanics and their inclusions. Trace-element geochemistry and rare-earth element modelling suggest that the two volcanoes developed from successive batches of similar parental magmas, originating from limited partial fusion of garnet peridotite in the mantle wedge. Various degrees of fractional crystallization ot these batches led to the formation of three volcanic suites: Hunter (little fractionated), West-Matthew (moderately fractionated) and East-Matthew (highly fractionated). Moreover, on Matthew island, no correlation exists between the degree of fractionation and the eruptive chronology, the youngest edifice (West-Matthew) being less evolved than the older on (East-Matthew). (Résumé d'auteur) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|