Simon Quentin, Ledru Marie-Pierre, Sawakuchi A. O., Favier C., Mineli T. D., Grohmann C. H., Guedes M., Bare E., Thouveny N., Garcia M., Tachikawa K., Rodriguez-Zorro P. A., ASTER Team. (2020). Chronostratigraphy of a 1.5 +/- 0.1 Ma composite sedimentary record from Colonia basin (SE Brazil) : bayesian modeling based on paleomagnetic, authigenic Be-10/Be-9, radiocarbon and luminescence dating. Quaternary Geochronology, 58, art. 101081 [18 p.]. ISSN 1871-1014.
Titre du document
Chronostratigraphy of a 1.5 +/- 0.1 Ma composite sedimentary record from Colonia basin (SE Brazil) : bayesian modeling based on paleomagnetic, authigenic Be-10/Be-9, radiocarbon and luminescence dating
Année de publication
2020
Auteurs
Simon Quentin, Ledru Marie-Pierre, Sawakuchi A. O., Favier C., Mineli T. D., Grohmann C. H., Guedes M., Bare E., Thouveny N., Garcia M., Tachikawa K., Rodriguez-Zorro P. A., ASTER Team
Source
Quaternary Geochronology, 2020,
58, art. 101081 [18 p.] ISSN 1871-1014
We present a new 52 m composite record (COL17c) composed of five sedimentary sequences retrieved from the Colonia basin (Southeastern Brazil). The COL17c record is composed of two main sub-units deposited under different regimes: a peatland above similar to 14 m and lacustrine sediments below. Sedimentary description and core scanning (MSCL and XRF) are first used to align individual cores in order to produce a nearly continuous composite record. We then established an original chronological framework based on radiocarbon, paleomagnetic, optically stimulated luminescence (OSL), post-infrared infrared stimulated luminescence at elevated temperature (pIRIR(290 degrees C)) and authigenic Be-10/Be-9 dating. We describe the protocols used for each technique and discuss the positive and negative results, as well as their implications for proxy interpretation. In spite of negative results of some techniques, mainly due to the absence of adequate sample material, the multi-proxy approach used is essential to maximize the chances of obtaining a satisfactory age model for this unique continental sedimentary sequence. All valid chronological proxies, comprising three AMS C-14 ages, one pIRIR(290 degrees C) age, two paleomagnetic constraints and eight authigenic Be-10/Be-9 datum, are integrated within a Bayesian age-depth modeling to produce a 1.5 +/- 0.1 Ma chronology for the whole COL17c sequence. This age model represents the first long-term chronological estimate of sediments deposition in the Colonia basin. The record allows to refine the age of the Colonia basin formation between 5.3 and 11.2 Ma, much older than previously estimated from short sedimentary cores.
Plan de classement
Géologie et formations superficielles [064]
;
Géophysique interne [066]
Description Géographique
BRESIL
Localisation
Fonds IRD [F B010078108]
Identifiant IRD
fdi:010078108
