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dc.contributor.authorLascu, Ioanen
dc.contributor.authorFeinberg, Joshua Men
dc.contributor.authorDorale, Jeffrey Aen
dc.contributor.authorCheng, Haien
dc.contributor.authorEdwards, R Lawrenceen
dc.date.accessioned2015-12-11T16:01:00Z
dc.date.available2015-12-11T16:01:00Z
dc.date.issued2016-01-04en
dc.identifier.citationLascu et al. Geology (2015) Vol. 44, Issue 2, pp. 139-142. doi:10.1130/G37490.1en
dc.identifier.issn0091-7613
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/252965
dc.description.abstractThe Laschamp geomagnetic excursion was the first short-lived polarity event recognized and described in the paleomagnetic record, and to date remains the most studied geomagnetic event of its kind. In addition to its geophysical significance, the Laschamp is an important global geochronologic marker. The Laschamp excursion occurred around the time of the demise of Homo neanderthalensis, in conjunction with high-amplitude, rapid climatic oscillations leading into the Last Glacial Maximum, and coeval with a major supervolcano eruption in the Mediterranean. Thus, precise determination of the timing and duration of the Laschamp excursion would help in elucidating major scientific questions situated at the intersection of geology, paleoclimatology, and anthropology. Here we present a North American speleothem geomagnetic record of the Laschamp excursion that is directly dated using a combination of high-precision 230Th dates and annual layer counting using confocal microscopy. We have determined a maximum excursion duration that spans the interval 42,250-39,700 yr BP, and an age of 41,100 ± 350 yr BP for the main phase of the excursion, during which the virtual geomagnetic pole was situated at the southernmost latitude in the record. Our chronology provides the first age bracketing of the Laschamp excursion using radioisotopic dating, and improves on previous age determinations based on 40Ar/39Ar dating of lava flows, and orbitally-tuned sedimentary and ice-core records.
dc.description.sponsorshipThis project was funded by NSF-EAR grant 1316385, a University of Minnesota McKnight Land Grant Professorship to JMF, and ERC grant 320750. Confocal microscopy was performed at the University of Minnesota Imaging Centers. We are grateful to John Geissman, Brad Singer, and James Channell for their constructive reviews. This is Institute for Rock Magnetism contribution 1506.
dc.languageEnglishen
dc.language.isoenen
dc.publisherGeological Society of America
dc.titleAge of the Laschamp excursion determined by U-Th dating of a speleothem geomagnetic record from North Americaen
dc.typeArticle
dc.description.versionThis is the author accepted manuscript. The final version is available from the Geological Society of America via http://dx.doi.org/10.1130/G37490.1en
prism.endingPage142
prism.publicationDate2016en
prism.publicationNameGeologyen
prism.startingPage139
prism.volume44en
rioxxterms.versionofrecord10.1130/G37490.1en
rioxxterms.versionAM
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2016-01-04en
dc.identifier.eissn1943-2682
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2017-01-04


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