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

Autor(es):Mostrar menos -

Simon, Quentin ^[1] ; Ledru, Marie-Pierre ^[2] ; Sawakuchi, Andre Oliveira ^[3] ; Favier, Charly ^[2] ; Mineli, Thays D. ^[3] ; Grohmann, Carlos H. ^[4] ; Guedes, Marco ^[4] ; Bare, Edouard ^[1] ; Thouveny, Nicolas ^[1] ; Garcia, Marta ^[1] ; Tachikawa, Kazuyo ^[1] ; Rodriguez-Zorro, Paula A. ^[2] ; Team, ASTER

Afiliação do(s) autor(es)

^[1] CEREGE, CNRS, IRD, INRAE, Coll France, UM34, F-13545 Aix En Provence - France

^[2] Univ Montpellier, ISEM, CNRS, IRD, EPHE, F-34095 Montpellier - France

^[3] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Inst Energia & Ambiente, BR-05508080 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: QUATERNARY GEOCHRONOLOGY; v. 58, JUN 2020.
• Citações Web of Science: 0

Resumo

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. (AU)

• Processo FAPESP: 13/50297-0 - Dimensions US-BIOTA São Paulo: integrando disciplinas para a predição da biodiversidade da Floresta Atlântica no Brasil
• Beneficiário: Cristina Yumi Miyaki
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático