This is a project to survey part of the Magdelena fan on the northern Columbian convergent margin using the GLORIA long range side-scan sonar system. This data together with 3.5 kHz profiling and single channel seismics will establish the plan view pattern of deformation. This pattern will allow a test of the hypothesis that the fan, because it imposes a low surface slope on the leading edge of the margin, may be suppressing the deformation in the offshore region. %%% Sediment fans deposited offshore from the mouths of rivers are important in the sedimentary record. Many modern fans (for example, the Mississippi and Amazon) are deposited on passive margins; others such as the Magdelena fan are deposited on convergent margins. It is surprising that the Magdelena fan is undeformed considering it is being deposited on a deforming margin. This survey will help address the problem of interaction between deformation and fan deposition at a convergent margin. The data will be useful for comparing modern and ancient fans that are deposited on convergent margins.
