Geomorphic processes within the La Gomera-Tenerife Channel (Canary Islands): Decoding the interaction of bottom currents with seabed topography

Abstract

The La Gomera-Tenerife Channel is a narrow passage between La Gomera and Tenerife Islands, i.e., two volcanic edifices of the Canary Archipelago (Atlantic Ocean). A geophysical study was conducted to identify the main geomorphic processes affecting the seabed and their interplay. In particular, submetric resolution bathymetric and side scan sonar backscatter data were collected in the southern sector of the Channel, down to 1200 m water depth. Their integrated analysis revealed a complex seabed morphology and a variety of morpho-sedimentary features, resulting from three main geomorphic processes: submarine volcanic activity, mass wasting (e.g., turbidity currents, small landslides and exotic blocks emplaced by a massive landslide event), and bottom currents activity. Bottom currents strongly reshaped the seabed into bedforms, confined drifts and moats. Although the flanks of volcanic islands are typically dominated by mass wasting and volcanic features, our results indicate that bottom current activity can be predominant in confined settings and around topographic features due to modification of flow patterns and enhancement of current flows.This study is the first to document volcanic, mass wasting and bottom current features within the La Gomera-Tenerife Channel. Furthermore, it provides insights on: i) morpho-sedimentary reconstructions of narrow passages between volcanic islands; ii) interplay among different geomorphic processes; iii) oceanographic reconstructions. The variety of geomorphic processes shaping the La Gomera-Tenerife Channel makes this area significant for high-resolution studies. Moreover, it provides new insights on poorly known processes, such as: the interaction of bottom currents with complex topography and bottom current morpho-dynamic in curved moats.