Home – Home – Jornals – Russian Geology and Geophysics 2002 number 7

Results of geological investigation of gas hydrate accumulation within the underwater sedimentary Blake Outer Ridge are presented. The study was based on both published and new data that we obtained by processing 164 and 172 ODP leg observations. The geological control over the distribution of gas hydrates is not quite clear despite the detailed seismic surveys and drilling within the study area. The geologic, tectonic, and hydro-geologic conditions in the Blake Outer Ridge area have been analyzed. A radically new technical approach was used: The gas hydrate accumulation was examined as a separate object with its specific characteristics. It has been proved that the investigated gas hydrates formed under the conditions of dissipated percolation of gas-containing fluids, which controlled the shape and the size of the accumulation. Based on geochemical, geophysical, and sedimentological data, the regularities of gas hydrate distribution within the Blake Outer Ridge have been established. The accumulation is controlled by tectonic factors, is of filtration origin, and occurs mainly in coarse-grained sediments.