Moquet J. S. auteur aut IRD Cruz F. W. auteur aut IRD Novello V. F. auteur aut IRD Strikis N. M. auteur aut IRD Deininger M. auteur aut IRD Karmann I. auteur aut IRD Santos R. V. auteur aut IRD Millo C. auteur aut IRD Apaestegui J. auteur aut IRD Guyot Jean-Loup auteur aut IRD Sifeddine Abdelfettah auteur aut IRD Vuille M. auteur aut IRD Cheng H. auteur aut IRD Edwards R. L. auteur aut IRD Santini William auteur aut IRD text journalArticle eng text/pdf born digital access delta O-18 in speleothems is a powerful proxy for reconstruction of precipitation patterns in tropical and sub-tropical regions. The aim of this study is to calibrate the delta O-18 record of speleothems against historical precipitation and river discharge data in central Brazil, a region directly influenced by the Southern Atlantic Convergence Zone (SACZ), a major feature of the South American Monsoon System (SAMS). The present work is based on a sub annual resolution speleothem record covering the last 141 years (the period between the years 1870 and 2011) from a cave in central Brazil. The comparison of this record with instrumental hydroclimate records since 1921 allows defining a strong relationship between precipitation variability and stable oxygen isotope ratios from speleothems. The results from a monitoring program of climatic parameters and isotopic composition of rainfall and cave seepage waters performed in the same cave, show that the rain delta O-18 variability is dominated by the amount effect in this region, while delta O-18 drip water remains almost constant over the monitored period (1.5 years). The delta O-18 of modern calcite, on the other hand, shows clear seasonal variations, with more negative values observed during the rainy season, which implies that other factors also influence the isotopic composition of carbonate. However, the relationship between delta O-18 of carbonate deposits and rainwater is supported by the results from the comparison between speleothem delta O-18 records and historical hydroclimate records. A significant correlation between speleothem delta O-18 and monsoon rainfall variability is observed on sub-decadal time scales, especially for the monsoon period (DJFM and NDJFM), once the rainfall record have been smoothed with a 7-9 years running mean. This study confirms that speleothem delta O-18 is directly associated with monsoon rainfall variability in central Brazil. The relationship between speleothem delta O-18 records and hydroclimatic historical records allows approximation of the absolute changes in mean annual rainfall during the last millennia in the SACZ/SAMS domain. specialized Speleothem Climate calibration Stable isotopes SAMS-SACZ Central Brazil BRESIL 062 021 064 139 151-164 2016 0921-8181 https://www.documentation.ird.fr/hor/fdi:010066804 10.1016/j.gloplacha.2016.02.001 0921-8181 [F B010066804] https://www.documentation.ird.fr/hor/fdi:010066804 https://www.documentation.ird.fr/intranet/publi/2016/05/010066804.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2016-06-02 2017-08-23 fdi:010066804 fre