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dc.contributor.authorMargalef, Olga-
dc.contributor.authorMartínez Cortizas, A.-
dc.contributor.authorKylander, M.-
dc.contributor.authorPla-Rabes, S.-
dc.contributor.authorCañellas-Boltà, Núria-
dc.contributor.authorPueyo, José Javier-
dc.contributor.authorSáez, Alberto-
dc.contributor.authorValero-Garcés, Blas L.-
dc.contributor.authorGiralt, Santiago-
dc.identifier.citationPalaeogeography Palaeoclimatology Palaeoecology 414 :438–450 (2014)es_ES
dc.description62 p., gráf, tablas -- Post-print del artículo publicado en Palaeogeography, Palaeoclimatology, Palaeoecology. Versión revisada y corregida.es_ES
dc.description.abstractWe analyze the geochemistry of Rano Aroi mire record (Easter Island) using bulk peat composition (C, N, S) and stable isotopes (δ13C, δ15N, δ34S) and major, minor and trace elemental compositions obtained by ICP-AES (Al, Ti, Zr, Sc, V, Y, Fe, Mn, Th, Ba, Ca, Mg and Sr). Peat geochemistry and the pollen record are used to reconstruct the environmental changes during the last 70 kyr BP. Principal component analysis on ICP-AES data revealed that three main components account for the chemical signatures of the peat. The first component, characterized by lithogenic elements (combined signal of V, Al, Sc, Y, Cr, Cd, Ti, Zr and Cu), evidences long-term changes in the basal fluxes of mineral material into the mire. This component, in combination with stable isotopes and pollen data suggests a link between soil erosion and vegetation cover changes in the Rano Aroi watershed. The second component is identified by the signal of Fe, Mn, Th, Ba, Zr and Ti, and is indicative of strong runoff events during enhanced precipitation periods. The third component (tied mainly to Ca, Sr and Mg) reflects a strong peat oxidation event that occurred during an arid period with more frequent droughts, sometime between 39 and 31 kyr BP. Correlation coefficients and a multiple regression model (PCR analysis) between peat organic chemistry and the principal components of ICP-AES analysis were calculated. Isotope chemistry of the peat organic matter further contributes to define Rano Aroi environmental history: δ13C data corroborates a vegetation shift documented by the palynological record from C4 to C3 between 55 and 45 cal kyr BP; the δ15N record identifies periods of changes in mire productivity and denitrification processes, while the δ34S peat signature indicates a marine origin of S and significant diagenetic cycling. The geochemical and environmental evolution of Rano Aroi mire is coherent with the regional climatic variability and suggests that climate was the main forcing in mire evolution during the last 70 kyr BP. The coupling of geochemical and biological proxies improves our ability to decipher depositional processes in tropical and subtropical peatlands and to use these sequences for paleoenvironmental and paleoclimate reconstructions.es_ES
dc.description.sponsorshipThis research was funded by the Spanish Ministry of Science and Education through the projects LAVOLTER (CGL2004-00683/BTE), GEOBILA (CGL2007-60932/BTE) and CONSOLIDER GRACCIE (CSD2007-00067) and an undergraduate grant JAE (BOE 04/03/2008) to Olga Margalef.es_ES
dc.subjectPeat recordes_ES
dc.subjectEaster Islandes_ES
dc.subjectStable isotopeses_ES
dc.subjectMajor and trace elementes_ES
dc.subjectEnvironmental reconstructiones_ES
dc.subjectPollen analysises_ES
dc.titleEnvironmental processes in Rano Aroi (Easter Island) peat geochemistry forced by climate variability during the last 70 kyres_ES
dc.description.peerreviewedPeer reviewedes_ES
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