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Cross-stratigraphies from a seismically active mud lens off Peru indicate horizontal extensions of laminae, missing sequences, and a need for multiple cores for high resolution records

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dc.contributor.author Salvatteci, R.
dc.contributor.author Field, D.
dc.contributor.author Sifeddine, A.
dc.contributor.author Ortlieb, L.
dc.contributor.author Ferreira, V.
dc.contributor.author Baumgartner, T.
dc.contributor.author Caquineau, S.
dc.contributor.author Velazco, F.
dc.contributor.author Reyss, J.-L.
dc.contributor.author Sanchez-Cabeza, J.-A.
dc.contributor.author Gutierrez, D.
dc.date.accessioned 2020-06-10T18:12:14Z
dc.date.available 2020-06-10T18:12:14Z
dc.date.issued 2014
dc.identifier.uri https://hdl.handle.net/20.500.12866/8058
dc.description.abstract Marine laminated sediments in dysoxic areas of the ocean floor are an excellent archive for high-resolution climate reconstructions. While the existence of discontinuities produced by natural events, such as underwater landslides (slumps), strong bottom currents, and/or bioturbation is usually acknowledged for long records, the extent of their influence on high-resolution sequences is usually not considered. In the present work we show strong evidence for multiple stratigraphic discontinuities in different gravity and box-cores retrieved off Pisco (Peru) covering the last 600years. Chronostratigraphies are largely based on cross-correlation of distinct sedimentary structures (determined by X-ray image analysis) and validated using 210Pb, 241Am, and 14C profiles, as well as proxy records. The cross-correlation of distinct stratigraphic layers allows for chronostratigraphic tie points and clearly shows that some sedimentary sequences are continuous across scales of tens of kilometers, indicating that regional processes often determine laminae formation. Some differences in laminae thickness were found among cores, which could be explained by different sedimentation rates, spatially variable deposition of diatom blooms, changes in silica dissolution and partial deposition/erosion caused by bottom currents. Using multiple stratigraphic tie points provides clear evidence for laminated sequences present in some cores to be missing in other cores. Moreover, instantaneous depositions from upslope were identified in all the cores disrupting the continuity of the sediment records. These discontinuities (instantaneous deposits and missing sequences) may be due to slumps, possibly triggered by earthquakes and/or erosion by strong bottom currents. In spite of the missing sequences in some cores, a continuous composite record of the last six centuries was reconstructed from spliced sequences of the different cores, which provides a well-constrained temporal framework to develop further high-resolution proxies in this region. The present work shows that paleoreconstructions developed from single cores, particularly in areas with strong seismic activity and/or strong bottom currents, are subject to both temporal gaps and instantaneous depositions from upslope, both of which could be misinterpreted as abrupt climate changes or anomalous climate events. We stress the need for multiple cores to determine the stratigraphic continuity and chronologies for high-resolution records. en_US
dc.language.iso eng
dc.publisher Elsevier
dc.relation.ispartof urn:issn:1872-6151
dc.rights info:eu-repo/semantics/restrictedAccess
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es
dc.subject Peru en_US
dc.subject sediment core en_US
dc.subject Ica en_US
dc.subject Pisco en_US
dc.subject Deposition en_US
dc.subject Earthquakes en_US
dc.subject paleoclimate en_US
dc.subject sedimentation rate en_US
dc.subject Sediments en_US
dc.subject correlation en_US
dc.subject Bacillariophyta en_US
dc.subject bottom current en_US
dc.subject chronostratigraphy en_US
dc.subject climate modeling en_US
dc.subject Composite record en_US
dc.subject Cross correlations en_US
dc.subject Cross-correlation en_US
dc.subject hiatus en_US
dc.subject Hiatus en_US
dc.subject High resolution en_US
dc.subject High-resolution records en_US
dc.subject Laminated composites en_US
dc.subject Laminated sediments en_US
dc.subject Lead en_US
dc.subject marine ecosystem en_US
dc.subject proxy climate record en_US
dc.subject resolution en_US
dc.subject sedimentary sequence en_US
dc.subject sedimentary structure en_US
dc.subject Sedimentology en_US
dc.subject seismic method en_US
dc.subject seismic stratigraphy en_US
dc.subject Slumps en_US
dc.subject spatial variation en_US
dc.subject stratigraphy en_US
dc.subject Stratigraphy en_US
dc.subject Submarine geology en_US
dc.subject temporal evolution en_US
dc.title Cross-stratigraphies from a seismically active mud lens off Peru indicate horizontal extensions of laminae, missing sequences, and a need for multiple cores for high resolution records en_US
dc.type info:eu-repo/semantics/article
dc.identifier.doi https://doi.org/10.1016/j.margeo.2014.07.008
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#3.02.00 es_PE
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#1.05.11
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#1.05.06
dc.subject.ocde https://purl.org/pe-repo/ocde/ford#1.05.04

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