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5th International Network for Submarine Canyon Investigation and Scientific Exchange International Symposium (INCISE), 14-18 June 2021, Submarine canyons are complex geomorphological features that have been identified as potential hotspots of biodiversity, which has led to many canyons being mapped and studied at high resolution (tens of meters). In this work, we present the first complete very-high resolution mapping of the Blanes submarine canyon in the northwestern Mediterranean, based on a compilation of swath bathymetry data acquired during different cruises, spanning between 2011 and 2020. The integrated data set completes and extends previous bathymetric datasets on the canyon rim and adjacent continental shelf acquired during the ESPACE programme in 2004. The grid spacing of the compilation map varies from 4 m for the canyon rim and adjacent shelf, 15 m for the head and upper canyon region and 25 m for the middle and lower canyon region. The Blanes Canyon deeply incises the continental shelf, showing an orientation parallel to the coastline at its head. Down-canyon, it displays a meandering course with a strong structural control, showing rectilinear canyon portions characterized by a flat-floored axis and steep terrains (>50º) on both canyon flanks, with the presence of networks of gullies and subhorizontal layered walls. The high resolution map has allowed to identify potential areas along the submarine canyon flanks that might provide suitable environmental conditions for hosting benthic ecosystems, particularly cold-water corals (CWCs). These sites were recently explored during the ABRIC Spanish National Project using the hybrid remotely operated vehicle (H-ROV) Ariane and the inspection-class ROV Liropus to explore the benthic communities and to collect specimen samples, complementing the previous ROV dataset acquired during the ABIDES Project. Collected data allowed for the compilation of an inventory of the most representative and relevant benthic species and communities observed within the Blanes Canyon. This information will be shared with the Blanes fishermen’s guild in the framework of an outreach project funded by the Fisheries Local Action Groups (GALP), to provide awareness of the presence and abundance of such vulnerable marine ecosystems in the Blanes Canyon, and to expand the spatial information provided by the ROV surveys by adding the local fishermen knowledg

National audience; In weathered volcanic tropical islands, geological studies are often limited due to the generally poorly outcropping conditions. Ground geophysical campaigns are also hard to perform due to difficult access in densely populated and forested areas. Recognition of geometric and petrographic characteristics of weathering mantles is a prerequisite to provide sustainable solutions to the management of natural hazards. In this particular context, airborne TDEM appears as a promising method to provide precise information about the Regolith. In 2010, the BRGM (the French geological survey) and the Prefecture of Mayotte decided to fund a geological mapping project including a heliborne TDEM resistivity survey of Mayotte. The SkyTEM helicopter borne transient; Dans les îles tropicales volcaniques, des études géologiques sont souvent limitées en raison des mauvaises conditions d'affleurement. Les campagnes de géophysique au sol sont difficiles à mettre en oeuvre compte tenu des difficultés d'accès dans des zones densément peuplées et boisées. La reconnaissance et la caractérisation géométriques et pétrographiques des manteaux d'altérites est un prérequis pour répondre aux demandes concernant, par exemple, la gestion des risques naturels. Dans ce contexte particulier, acquérir des données TDEM aéroportées apparaît comme la méthode la plus appropriée pour fournir des informations précises sur le régolithe. En 2010, le BRGM et la préfecture de Mayotte ont décidé de financer un projet de cartographie géologique, incluant un levé de résistivité TDEM héliporté sur l'ensemble de Mayotte. La méthode électromagnétique a été choisie afin d'obtenir une image de la résistivité quasi-3D de l'île. De bons contrastes de conductivité (de 1 à 600 ohm.m) entre les différents types de roches ont permis de définir la géométrie des principales unités géologiques, jusqu'à une profondeur de 200 m. Les premiers résultats sont très prometteurs et ont montré qu'il s'agit d'un outil puissant pour la cartographie de régolithe et en particulier la cartographie des profils d'altération.