1.
Appl Radiat Isot
; 65(7): 776-83, 2007 Jul.
Artigo
em Inglês
| MEDLINE
| ID: mdl-17446079
RESUMO
(238)U and its radiogenic daughter (234)U have been utilized for dating soil formation and groundwater residence time during the last 1.5 million years, in this case based on the U-dissolution/precipitation occurring during modifications of the oxidation-reduction conditions. In this paper, we report a 400-600kyr proxy of wet periods from sediments occurring in a soil profile developed over rocks outcropping at the Paraná sedimentary basin in Brazil, and from groundwater exploited of Guarani aquifer at the same basin. The approaches indicated successful use of the U-modeled ages for suggesting wet periods exceeding the past 116-210kyr from previous studies.