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dc.contributor.authorBonatto, Len
dc.contributor.authorPiromallo, Cen
dc.contributor.authorCottaar, Sanneen
dc.date.accessioned2020-10-12T23:30:33Z
dc.date.available2020-10-12T23:30:33Z
dc.date.issued2020-08-13en
dc.identifier.issn2169-9313
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/311376
dc.description.abstract©2020. American Geophysical Union. All Rights Reserved. We investigate the mantle transition zone beneath the Chile-Argentina flat subduction region by means of P-to-S conversions at mantle discontinuities from teleseismic events recorded at 103 seismic stations. From the analysis of receiver functions, we obtain clear converted phases from the 410 and 660 discontinuities, and we identify a robust precursory signal to P660s, of negative amplitude, that we name P590s. We observe little frequency dependence in the amplitude of the P410s converted phase, while the P660s is less visible toward higher frequencies. The 410 is on average deeper than 410 km by 10 ± 1 km in the higher-frequency bands, and it is relatively sharp, being consistent with a 10% velocity jump over less than 20 km. The observed 660 depth varies with frequency; it is deeper by up to 18 ± 2 km for lower frequencies and close to reference at higher frequencies, being consistent with a 13% broad velocity gradient over 30–40 km, probably caused by a composite of multiple phase transitions. The transition zone thickness is controlled by the frequency-dependent depth variability of the 660. Our findings of relative depth, width, and velocity jump of the detected discontinuities, combined with tomographic images of the mantle transition zone, cannot be explained by thermal variations alone. Compositional constraints from mineral physics show that a near pyrolitic mantle is consistent with the ratio of the estimated velocity jumps. However, the negative P590s phase in this region could be signal from the velocity reduction due to basalt accumulation at the base of the transition zone.
dc.rightsAll rights reserved
dc.rights.uri
dc.titleThe Transition Zone Beneath West Argentina-Central Chile Using P-to-S Converted Wavesen
dc.typeArticle
prism.issueIdentifier8en
prism.publicationDate2020en
prism.publicationNameJournal of Geophysical Research: Solid Earthen
prism.volume125en
dc.identifier.doi10.17863/CAM.58466
dcterms.dateAccepted2020-07-25en
rioxxterms.versionofrecord10.1029/2020JB019446en
rioxxterms.versionAM
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2020-08-13en
dc.contributor.orcidCottaar, Sanne [0000-0003-0493-6570]
dc.identifier.eissn2169-9356
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idNERC (NE/R010862/1)
pubs.funder-project-idEuropean Commission Horizon 2020 (H2020) ERC (804071)
cam.issuedOnline2020-07-29en
cam.orpheus.successMon Oct 19 07:30:30 BST 2020 - Embargo updated*
rioxxterms.freetoread.startdate2021-01-29


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