Recent transfer of coastal sediments to the Laurentian Channel, Lower St. Lawrence Estuary (Eastern Canada), through submarine canyon and fan systems

摘要: Multibeam sonar data, acoustic sub-bottom profiles and box cores were used to study the activity of submarine canyons fans near city Les Escoumins, on North Shore Lower St. Lawrence Estuary (Eastern Canada). The multibeam data generate a high-resolution digital terrain model that reveals presence large number along northern slopes Laurentian Channel. This paper focuses two larger canyons, their associated fans. reveal high-amplitude reflections at sediment/water interface seafloor surface, indicating occurrence layers coarse material. A turbidite was observed in core sampled one fans, confirming nature layer. Geophysical sedimentological indicate play an important role transferring coastal sandy sediments deeper marine environments by longshore drift-initiated turbidity flows, thereby contribute negative sediment budget coast. morphology indicates they produced combination erosive flows retrogressive failures. recent (~last 60 years) quasi-exponential increase sand content surface cores, possibly reflecting deforestation and/or increased erosion.