Resumen de Evidencias de gas en los sedimentos marinos de la zona interna de la Ría de Arosa, Galicia
Raquel Díez Arenas, A.G. Judd, Soledad García Gil, Federico Vilas Martín
Direct and indirect evidence of the presence of shallow gas have been identified in the sediments of the internal part of the Ría de Arosa (NW of Spain). Sub-bottom and echo sounder records reveal pockmark-like features and gas seeps in the water column. Seismic and sub-bottom profiler records have also been collected. They are useful tools for the detection of gas accumulations. A large gas accumulation field has been identified underlying the features cited. The depth of the gas varies, in some areas it reaches the seabed. Also, some other gas related features have been identified. These are: a) seabed domes associated with a local volume increase in the sediments caused by shallow gas, interpreted as the first stage of pockmark formation, b) dark patches in the side scan sonar record, products of the exposure of the underlying coarser material by gas seep activity.
