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Reevaluation of magnetic chrons in the North Atlantic between 35 degrees N and 47 degrees N: implications for the formation of the Azores Triple Junction and associated plateau

2008-10Journal article Open access
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dc.contributor.authorLuis, Joaquim
dc.contributor.authorMiranda, J. M.
dc.date.accessioned2018-12-07T14:58:08Z
dc.date.available2018-12-07T14:58:08Z
dc.date.issued2008-10
dc.description.abstractIn this paper we present a new magnetic compilation for an area of the North Atlantic located between 35 degrees N and 47 degrees N and up to anomaly 33r. We also present a strategy to pick magnetic isochrones and compute finite rotation poles. This technique is based on a continuous reduction to the pole technique and some basic assumptions regarding the direction of the remanent magnetization vector. A cost function that measures the misfit between interpreted and rotated isochrones and the systematic exploitation of the parameter space is used to compute the best set of finite Eulerian rotations for the chrons 5, 6, 6C, 11-12, 13, 18, 20, 21, 22, 23, 24, 25, 26, 28, 29, 30, 32, 33, and 33r. This set of chrons and poles is used to discuss the evolution of the North Atlantic close to Iberia and, in particular, the onset and early development of the Azores Triple Junction area. We show that the relative motion between the Eurasian and the African plates can be coherently described in terms of rigid plate kinematics, respecting both the anomalies shapes and the precise location of the main structural elements of the area: the Pico Fracture Zone, the East Azores Fracture Zone, and the Gloria Fault. We distinguish from the magnetic point of view two different areas of the Azores plateau: the South Azores domain where almost undisturbed NNW magnetic lineations can be found and the Azores domain close to the topographic highs and with no systematic magnetic stripping with the exception of a few recent lineations, probably Matuyama and Brunhes. We present an approximate reconstruction of the plate configuration after chron 18 to conclude that the attachment of Iberia to Eurasia was younger than previously thought (lower Miocene), triggering the formation of the Azores domain, in which stretching took place essentially in the last 20 Ma at an average rate of similar to 3.8 mm/a, and progressively attaching the South Azores domain to the African plate by a northward progression of the triple junction.
dc.description.sponsorshipFCT/FEDER [STRIPAREA POCI/CTE-GIN/59653/2004]
dc.identifier.doi10.1029/2007JB005573
dc.identifier.issn2169-9313
dc.identifier.issn2169-9356
dc.identifier.urihttp://hdl.handle.net/10400.1/11875
dc.language.isoeng
dc.peerreviewedyes
dc.publisherAmerican Geophysical Union (AGU)
dc.subjectDifferential reduction
dc.subjectRidge
dc.subjectKinematics
dc.subjectBoundaries
dc.subjectAnomalies
dc.subjectGravity
dc.subjectEurasia
dc.subjectHotspot
dc.subjectAfrica
dc.subjectIberia
dc.titleReevaluation of magnetic chrons in the North Atlantic between 35 degrees N and 47 degrees N: implications for the formation of the Azores Triple Junction and associated plateau
dc.typejournal article
dspace.entity.typePublication
oaire.citation.issueB10
oaire.citation.startPageB10105
oaire.citation.titleJournal of Geophysical Research-Solid Earth
oaire.citation.volume113
person.familyNameLuis
person.givenNameJoaquim
person.identifier.ciencia-id0D11-8EF9-2E68
person.identifier.orcid0000-0002-9035-4069
person.identifier.ridA-1112-2009
person.identifier.scopus-author-id7006391353
rcaap.rightsopenAccess
rcaap.typearticle
relation.isAuthorOfPublication636a16a1-f50a-49d2-9d5c-dbc3444815bd
relation.isAuthorOfPublication.latestForDiscovery636a16a1-f50a-49d2-9d5c-dbc3444815bd

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