Towards a Better Knowledge of Natural Methane Releases in the French Alps: A Field Approach

Figure 9

MG site: (top) overviews of reliefs surrounding the site and relief-shaped geological map (from Google Earth); location of the gas seep is indicated by the yellow star; MO: shales from the Middle Oxfordian age; UCLO: black shales from the Upper Callovian to the Lower Oxfordian age. (Middle) Photograph of the site and main thalwegs (dotted lines); right inset: aerial view of thalwegs (from Google Earth); left inset: topography of the seepage area (the character is in front of the seep). (Bottom) Locations of passive atmosphere monitoring (A, B, and C) and results of CH₄ measurements.