Seabed topography of a deep-water channel and nearby abyssal mount area south of the Azores, Eastern North Atlantic: Evidence of tectonic activity, erosion, and bottom current action

Detailed multibeam bathymetric mapping in combination with 3.5 kHz sub-bottom profiling, seabed video observations, sediment coring and hydrographic (CTD) measurements were performed in a deep-water area south of the Azores, Eastern North Atlantic Ocean. The study site is located immediately north of an UN-designated large marine protection area including the Atlantis-Meteor Seamount Complex. This seamount area represents a deep-sea benthic environment characterized by a vulnerable marine ecosystem with a large, partly unknown, biodiversity. Spatial distribution of deep-sea biodiversity is mainly driven by seabed topography and bottom water conditions, which are the main topics addressed in the present study. The seabed data collected during two cruises with RV’Pelagia’ (Royal NIOZ) provides evidence of significant (retrogressive) erosion patterns and local tectonic activity. A variety of larger and smaller erosional and sedimentary structures and the limited distribution of fine-grained bedded sediments are interpreted to have resulted from a combination of local hydrodynamic processes and tectonic activity. This new seabed information acquired in our study will thus contribute to a better understanding of the role of (near) seabed dynamics and topography in controlling deep-water biodiversity south of the Azores. • Collection of new high resolution bathymetric, oceanographic, video, sediment and acoustic sub-bottom data. • Different types of observations all fit into wider oceanographic setting. • New results support existing theories on regional tectonic evolution and oceanography.