Métodos elétricos e eletromagnéticos voltados à interpretação do comportamento hídrico de solos na cabeceira do Rio São Lourenço-MT

Abstract

The geophysical methods are being used increasingly in hydrogeological and geo- environmental studies. The presence of water in the pores and/or fractures in the rock causes

an increase in electrical conductivity of the medium, allowing the use of electric and electromagnetic methods to assist in determining the depth, sidebar extension, thickness and volume of soil and/or rock. In this work, the study area is located in one of the watersheds of the mouth of the St. Lawrence River, near to the city of green field, MT, Brazil. The goal is to characterize the pedological coverage and its substrate, into two strands of watershed in study, through application of methods of handling electric and inductive electromagnetic pathway. For determining the thickness of the soil and the top of the water table was applied Electroresistivity method with the technique of walking with electric Dipole-Dipole with 4 levels of research, 5 m, 7 m, 10 m and 12 m. The second method used was the Electromagnetic Inductive method to determine moisture variations of soil and rock layers. Were used three spacing between the coils, investigating 4 different theoretical depths: 7, 5 m, 15 m, 30 m and 60 m. Withdrawals were made in four lines of 100 m, two on each strand. Resistivity profiles differ for each side of the shed studied. Lines 1 and 2 that if they find of one same side, are differed from lines 3 and 4, that it can be explained by the domain of Yellow Latossolo that characterizes a pedological covering with trends to the infiltration of rain waters throughout the source. Already for the other source Gleissolo in the inferior portion was found, Plintossolo in the region central of the line and Latossolo in the upper portion.