Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu)
Abstract The subduction zones in the SW Pacific Ocean are some of the most dynamic plate boundaries on Earth with changes in subduction polarity and subduction initiation processes. The New Hebrides island arc formed some 10 million years ago after the Melanesian island arc was abandoned due to the...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Wiley
2024-02-01
|
| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2023GC011187 |
| _version_ | 1827318430438522880 |
|---|---|
| author | K. M. Haase K. P. Schneider B. Pelletier O. Ishizuka |
| author_facet | K. M. Haase K. P. Schneider B. Pelletier O. Ishizuka |
| author_sort | K. M. Haase |
| collection | DOAJ |
| description | Abstract The subduction zones in the SW Pacific Ocean are some of the most dynamic plate boundaries on Earth with changes in subduction polarity and subduction initiation processes. The New Hebrides island arc formed some 10 million years ago after the Melanesian island arc was abandoned due to the cessation of subduction of the Pacific Plate after collision of oceanic plateaus with the island arc. Parts of the Melanesian island arc occur within the New Hebrides island arc and we show that Miocene volcanic rocks exposed on Malekula island in the New Hebrides island arc consist of island arc tholeiites to alkaline basalts with variable slab contribution. The lava erupted between 22.5 and 16.3 Ma, similar to the Wainimala Group lavas on Fiji representing the eastern portion of the Melanesian island arc. Partial melts from subducted sediments affected a Pacific MORB‐type mantle, but we do not find evidence for a slab component derived from the Ontong Java Plateau or for assimilation of continental crust. Thus, no Miocene subduction of the Ontong Java Plateau occurred beneath Malekula and the basement of the island probably does not consist of continental crust rifted from Australia. The Malekula lava succession resembles that of other portions of the Miocene Melanesian island arc between New Britain and Fiji, indicating continuous subduction of the Pacific plate along this arc. |
| first_indexed | 2024-03-07T21:34:12Z |
| format | Article |
| id | doaj.art-f3e7bdc711004f2cbf2dd59b3ad5199a |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-04-24T23:57:45Z |
| publishDate | 2024-02-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-f3e7bdc711004f2cbf2dd59b3ad5199a2024-03-14T10:55:31ZengWileyGeochemistry, Geophysics, Geosystems1525-20272024-02-01252n/an/a10.1029/2023GC011187Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu)K. M. Haase0K. P. Schneider1B. Pelletier2O. Ishizuka3GeoZentrum Nordbayern Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU) Erlangen GermanyGeoZentrum Nordbayern Friedrich‐Alexander‐Universität Erlangen‐Nürnberg (FAU) Erlangen GermanyInstitut de Recherche pour le Développement Nouméa Nouvelle‐CalédonieInstitute of Earthquake and Volcano Geology Geological Survey of Japan AIST Ibaraki JapanAbstract The subduction zones in the SW Pacific Ocean are some of the most dynamic plate boundaries on Earth with changes in subduction polarity and subduction initiation processes. The New Hebrides island arc formed some 10 million years ago after the Melanesian island arc was abandoned due to the cessation of subduction of the Pacific Plate after collision of oceanic plateaus with the island arc. Parts of the Melanesian island arc occur within the New Hebrides island arc and we show that Miocene volcanic rocks exposed on Malekula island in the New Hebrides island arc consist of island arc tholeiites to alkaline basalts with variable slab contribution. The lava erupted between 22.5 and 16.3 Ma, similar to the Wainimala Group lavas on Fiji representing the eastern portion of the Melanesian island arc. Partial melts from subducted sediments affected a Pacific MORB‐type mantle, but we do not find evidence for a slab component derived from the Ontong Java Plateau or for assimilation of continental crust. Thus, no Miocene subduction of the Ontong Java Plateau occurred beneath Malekula and the basement of the island probably does not consist of continental crust rifted from Australia. The Malekula lava succession resembles that of other portions of the Miocene Melanesian island arc between New Britain and Fiji, indicating continuous subduction of the Pacific plate along this arc.https://doi.org/10.1029/2023GC011187subductionpolarity reversalisland arc evolutionNew Hebrides island arcHf‐Nd isotope ratiosVitiaz island arc |
| spellingShingle | K. M. Haase K. P. Schneider B. Pelletier O. Ishizuka Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) Geochemistry, Geophysics, Geosystems subduction polarity reversal island arc evolution New Hebrides island arc Hf‐Nd isotope ratios Vitiaz island arc |
| title | Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) |
| title_full | Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) |
| title_fullStr | Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) |
| title_full_unstemmed | Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) |
| title_short | Magmatic Evolution of the Fossil Melanesian Island Arc: Evidence From Lower Miocene Lavas of Malekula Island (Vanuatu) |
| title_sort | magmatic evolution of the fossil melanesian island arc evidence from lower miocene lavas of malekula island vanuatu |
| topic | subduction polarity reversal island arc evolution New Hebrides island arc Hf‐Nd isotope ratios Vitiaz island arc |
| url | https://doi.org/10.1029/2023GC011187 |
| work_keys_str_mv | AT kmhaase magmaticevolutionofthefossilmelanesianislandarcevidencefromlowermiocenelavasofmalekulaislandvanuatu AT kpschneider magmaticevolutionofthefossilmelanesianislandarcevidencefromlowermiocenelavasofmalekulaislandvanuatu AT bpelletier magmaticevolutionofthefossilmelanesianislandarcevidencefromlowermiocenelavasofmalekulaislandvanuatu AT oishizuka magmaticevolutionofthefossilmelanesianislandarcevidencefromlowermiocenelavasofmalekulaislandvanuatu |