Repository logo
 
Publication

Multi-stage evolution of a sub-aerial volcanic ridge over the last 1.3 Myr: S. Jorge Island, Azores triple junction

2008-09-15Journal article Open access
Simple item page
dc.contributor.authorHildenbrand, Anthony
dc.contributor.authorMadureira, Pedro Miguel
dc.contributor.authorMarques, Fernando Ornelas
dc.contributor.authorCruz, Inês
dc.contributor.authorHenry, Bernard
dc.contributor.authorSilva, Pedro
dc.date.accessioned2012-03-21T18:57:42Z
dc.date.available2012-03-21T18:57:42Z
dc.date.issued2008-09-15
dc.description.abstractNew K/Ar dating and geochemical analyses have been carried out on the WNW-ESE elongated oceanic island of S. Jorge to reconstruct the volcanic evolution of a linear ridge developed close to the Azores triple junction. We show that S. Jorge sub-aerial construction encompasses the last 1.3 Myr, a time interval far much longer than previously reported. The early development of the ridge involved a sub-aerial building phase exposed in the southeast end of the island and now constrained between 1.32 +/- 0.02 and 1.21 +/- 0.02 Ma. Basic lavas from this older stage are alkaline and enriched in incompatible elements, reflecting partial melting of an enriched mantle source. At least three differentiation cycles from alkaline basalts to mugearites are documented within this stage. The successive episodes of magma rising, storage and evolution suggest an intermittent reopening of the magma feeding system, possibly due to recurrent tensional or trans-tensional tectonic events. Present data show a gap in sub-aerial volcanism before a second main ongoing building phase starting at about 750 ka. Sub-aerial construction of the S. Jorge ridge migrated progressively towards the west, but involved several overlapping volcanic episodes constrained along the main WNW-ESE structural axis of the island. Malic magmas erupted during the second phase have been also generated by partial melting of an enriched mantle source. Trace element data suggest, however, variable and lower degrees of partial melting of a shallower mantle domain, which is interpreted as an increasing control of lithospheric deformation on the genesis and extraction of primitive melts during the last 750 kyr. The multi-stage development of the S. Jorge volcanic ridge over the last 1.3 Myr has most likely been greatly influenced by regional tectonics, controlled by deformation along the diffuse boundary between the Nubian and the Eurasian plates, and the increasing effect of sea-floor spreading at the Mid-Atlantic Ridge.por
dc.identifier.citationHILDENBRAND, Anthony; [et al] – Multi-stage evolution of a sub-aerial volcanic ridge over the last 1.3 Myr: S. Jorge Island, Azores triple junction. Earth and Planetary Science Letters. ISSN 0012-821X. Vol. 273, N.º 3-4 (2008), pp. 289-298.por
dc.identifier.doi10.1016/j.epsl.2008.06.041
dc.identifier.issn0012-821X
dc.identifier.urihttp://hdl.handle.net/10400.21/1323
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherElsevier Science BVpor
dc.subjectSao Jorgepor
dc.subjectAzores triple junctionpor
dc.subjectMARpor
dc.subjectK/Arpor
dc.subjectGeochemistrypor
dc.subjectVolcanic ridge evolutionpor
dc.titleMulti-stage evolution of a sub-aerial volcanic ridge over the last 1.3 Myr: S. Jorge Island, Azores triple junctionpor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.conferencePlaceNetherlandspor
oaire.citation.endPage298por
oaire.citation.issue3-4por
oaire.citation.startPage289por
oaire.citation.titleEarth and Planetary Science Letterspor
oaire.citation.volume273
person.familyNameHildenbrand
person.familyNameMadureira
person.familyNameMarques
person.familyNameHenry
person.familyNameSilva
person.givenNameAnthony
person.givenNamePedro Miguel
person.givenNameFernando Ornelas
person.givenNameBernard
person.givenNamePedro
person.identifier1232178
person.identifier.ciencia-id011D-F457-BAB6
person.identifier.ciencia-idBD11-66D7-5BC3
person.identifier.ciencia-idC314-1157-FD0C
person.identifier.orcid0000-0002-1406-7252
person.identifier.orcid0000-0003-4762-6273
person.identifier.orcid0000-0002-9163-6084
person.identifier.orcid0000-0003-2715-8636
person.identifier.orcid0000-0002-9178-3623
person.identifier.ridF-4892-2010
person.identifier.ridB-7120-2008
person.identifier.ridB-8512-2008
person.identifier.scopus-author-id24503642500
person.identifier.scopus-author-id7102759947
person.identifier.scopus-author-id7102689952
person.identifier.scopus-author-id55431034700
rcaap.rightsrestrictedAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublication36f07c21-1fee-4813-9d01-bfa16e5b4636
relation.isAuthorOfPublicationece1fd98-1fe8-4861-9bf9-918edcedbd9f
relation.isAuthorOfPublicationb76d3ca9-383c-4aed-b571-cac6fb806503
relation.isAuthorOfPublication48b19af8-b3de-40ab-b8e3-9feac4d41f65
relation.isAuthorOfPublication54c96e27-8c3a-42d9-b751-ebc637c2f478
relation.isAuthorOfPublication.latestForDiscovery54c96e27-8c3a-42d9-b751-ebc637c2f478

Files

Original bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
Multi-stage_PSilva.pdf
Size:
1.09 MB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download

Collections

ISEL - Eng. Civil - Artigos