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dc.contributor.author
Nami, Hugo Gabriel
dc.date.available
2017-01-18T21:34:17Z
dc.date.issued
2015-03
dc.identifier.citation
Nami, Hugo Gabriel; New Paleomagnetic results and evidence for a geomagnetic field excursion during the pleistocene-holocene transition at Pichincha province, Ecuador; Elsevier; Geofísica Internacional; 54; 2; 3-2015; 127-148
dc.identifier.issn
0016-7169
dc.identifier.uri
http://hdl.handle.net/11336/11623
dc.description.abstract
Paleomagnetic data from three sedimentary sections in Pichincha province -Quito City (QC), Mullimica (Mu) and El Tingo (ET)- Ecuador (northwestern South America) are reported. Analysis of natural remanent magnetization directions obtained from 109 oriented samples taken at 4 sites, shows that some samples recorded a magnetic component different from the normal present geomagnetic field (GMF). The characteristic remanent magnetization (ChRM) was determined by progressive AF demagnetization. The analysis shows that the sections recorded ChRM of normal, intermediate and reverse polarities during the Pleistocene-Holocene transition and Holocene. Normal directions were recorded in QC, while normal and intermediate polarity directions at Mu and, reverse VGPs at ET. QC and the upper portion of Mu correspond to the paleosecular variation Holocene record for Ecuador during the ~≤4.7 ka BP. On the other hand, the lower portion of Mu logs represents the transition from normal to intermediate directions occurring at ~≥5.6 ka BP. Sites from ET recorded two stable oblique reverse records with a large fluctuation far from the present GMF at ~10.5 ka BP. The transitional virtual geomagnetic poles generally agree with those registered during the possible Pleistocene-Holocene excursion observed in other places of the planet. When plotted in a present world map, VGPs calculated from normal samples at QC are very well clustered in Northern North America, Greenland and Northern Europe; most VGP´s calculated from Mu are situated between 30 and 60 northern latitude in Northern North America, Greenland, western Europe, Africa and North Pacific Ocean. Interestingly, the majority of the reverse directions from ET conforms a patch located in southern Africa, and a few ones are situated in central Africa, eastern Australia and Antarctica. An Ecuadorian paleopole was calculated with data resulting from QC and Mu. Also other paleopoles of the same age were processed from other North and South American sites. Remarkably they agree well, although they do not agree with the geographical pole showing ~15° angular difference in relation to the rotation´s axis of the Earth. Finally, is discussed the hypothesis of the global excursional state of the GMF during the last ~11.0 ka BP and the potential use as dating tool the excursion dated at 10.5 ka BP.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
dc.subject
Paleomagnetism
dc.subject
Paleosecular Variation
dc.subject
Excursion
dc.subject
Pleistocene-Holocene Transition
dc.subject.classification
Geoquímica y Geofísica
dc.subject.classification
Ciencias de la Tierra y relacionadas con el Medio Ambiente
dc.subject.classification
CIENCIAS NATURALES Y EXACTAS
dc.title
New Paleomagnetic results and evidence for a geomagnetic field excursion during the pleistocene-holocene transition at Pichincha province, Ecuador
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2016-12-07T18:13:55Z
dc.journal.volume
54
dc.journal.number
2
dc.journal.pagination
127-148
dc.journal.pais
México
dc.description.fil
Fil: Nami, Hugo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina
dc.journal.title
Geofísica Internacional
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S0016716915000100
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.gi.2015.04.009
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.redalyc.org/articulo.oa?id=56836855002


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    Articulos de INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BS. AS

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