Study of Sediment Waves Formation and Morphology in Turbidite Systems from Physical Modelling Perspective

Del Rey, Antonio Cosme¹, Rafael Manica², Rogério Dornelles Maestri², Ana Luiza de Oliveira Borges², Adriano R. Viana³ (1) Petrobras - Petroleo Brasileiro S.A, Vitoria, Brazil (2) Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil (3) Petrobras, Rio de Janeiro, Brazil

The study of sediment wave generation and morphology in turbidite systems has been highlighted in some recent papers; however the study in laboratory concerning these sedimentary structures hasn't been discussing a lot. Thus, this work aims presents the results of twelve simulations in a small-scale physical simulation comparing the sediment waves generated in laboratory with natural turbidite systems through seismic data and outcrops studies. In order to achieve this objective, an ancient turbidity system of Eastern Brazilian continental margin was selected as prototype for flume experiments. Its natural complex geometry was substituted by simplified geometry (straight channel and basin) and then, this new topography was implanted inside the small-scale model. The simulations showed the sediment wave formation along the channel. Bedforms sequence was identified ranging from linear to linguoid-type ripples. It was also observed a cross-correlation between wave length and amplitude of these bedforms, however different flow conditions cause changes in their geometry. On the overbank zone of the channel, the deposits present ripples with the same direction as the flow (downstream direction) while in the basin, the sediment wave present elongate shape and perpendicular direction instead. The sedimentary structures generated in these experiments were identified and compared with different seismic data of recent turbidite system in the East Brazilian continental margin as well as with natural outcrops observed in the Brushy Canyon Fm (TX, USA), Itajaí Basin (SC, Brazil) and Almada Basin (BA, Brazil). The results of these three approaches are discussed.