Uso de estimativas de paleoprecipitação e paleotemperatura em paleossolos cretáceos no Brasil: abordagem crítica

Márcio Luiz da Silva, Alessandro Batezelli, Francisco Sergio Bernardes Ladeira

Abstract


This paper aims to discuss the applicability and limitations of paleoprecipitation and paleotemperature estimate in paleosols of Marilia Formation, Upper Cretaceous of the Bauru Basin. Three sections have been described (A1, A2 and A3) comprising nine profiles. The major, minor and trace elements were determined by X-Ray Fluorescence and the estimative were based on exponential equations and linear regressions. In the Marilia Formation the paleosols were developed in sandstones and are characterized by clay horizons (Btk and Bt) and carbonate horizons (Bk) with different degrees of cementation (calcretes). The paleosols with Bk showed average values of 420 and 500 mm/year, respectively, for the Botucatu sections (A1) and Garça (A3). In the paleosols with Bt, the average of the paleoprecipitations 881 mm/year and the average annual of the paleotemperature was 10° C. Paleosols with Btk showed average values of the paleoprecipitation of 605 mm/year. Precipitation variations, taken individually and inductively, provided the definition of three paleoclimate intervals for the Maastrichtian of the Bauru Basin. However, the variability of both vertical and horizontal soil properties and the use of this technique as the primary method unfeasible the use of climofunções, which have not reached consensus in paleoclimate study.

Keywords


Calcrete; Climofunctions; Paleoclimate; Bauru Basin; Marília Formation.



DOI: http://dx.doi.org/10.21715/GB2358-2812.2016301072

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