Large transverse bedforms in a mesotidal estuary

DIANA G. CUADRADO; EDUARDO A. GÓMEZ; SILVIA SUSANA GINSBERG

AAS revista

Asociación Argentina de Sedimentología

Año: 2004 vol. 10 p. 163 - 172

0328-1159

Large transverse bedforms occur on shallow continental shelves, tidal inlets and large estuaries as a result of the strong currents in water sufficiently deep. Although Bahia Blanca Estuary is not a large estuary, its topographical and hydrodynamical characteristics allow the development of a dune field including, among other bedforms, very large dunes. Such large bedforms are rare in this kind of estuary. Large, submerged dunes of Ballia Blanca Estuary were studied to acquire additional knowledge of the difrerc~it morphologies found in nature, their relationships with the dynamics of the area and the mechatlisnis involved inin their formation. To do this, the dunes field was surveyed in detailed and classified according to lieight, spacing, superposition, sediment characteristics, flow stn~cti~arned history. Side scan sonar and echo-sounder records were used to analyze the lieight and spacing and shape of the dunes. The results of several current metcrs deployed in the study area were used to analyze the flow structure. The current velocities and the characteristics of the bottom sediments were related to the bedforms in order to understand the factors controlling their formation.