MORPHOLOGICAL CHARACTERIZATION OF ANCIENT AEOLIAN DUNES USING THE GROUND-PENETRATING RADAR, BOTUCATU FORMATION, SOUTHERN BRAZIL

FERNANDA GUILARDI DA SILVA, CLAITON MARLON DOS SANTOS SCHERER

Resumo


This paper presents ground-penetrating radar (GPR) profiles obtained from an aeolian dune of the Botucatu Formation. A 50 MHz antenna was used and an excellent resolution was achieved down to 10 m deep. GPR surveys have allowed a detailed reconstruction of the bed morphology. In the parallel to the foreset dip GPR section the reflectors that delineate the cross bedding are straight and steep whereas in the transversal section they are subhorizontal. This configuration indicates a bedform with straight to slightly wavy crestline (2D). Third- and first-order bounding surfaces were interpreted from the termination of the reflectors' sets. The presence of several third-order-bounding surfaces suggests either an aeolian dune subject to cyclical fluctuations of its height or reverse dune. The identification of a first-order bounding surface indicates climbing and accumulation of dunes in the studied area.

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