Deeper hydrates at Southern Hydrate Ridge characterization and assessment

2 Deeper hydrates at Southern Hydrate Ridge characterization and assessment 

Even with the high concentrations of the near-surface hydrates, the deeper ( 20 m) hydrate deposits contain most of the gas in the hydrated reservoir. This deeper hydrated gas is mostly biogenic, with anecdotal incidents of 10% thermogenic gas. 

FIGURE 7.25 The position of five off-summit drill sites at southern Hydrate Ridge. Note the under-thrust sediments of the accretionary complex labeled AC. The reflections labeled A, B, and B result from gas-charged, coarse-grained sediments. (From Trehu, A.M., et al., Earth Planet Sci. Lett., 222, 845 (2004b). With permission from Elsevier.) 

FIGURE 7.26 (See color insert following page 390.) Site 1245A southern Hydrate Ridge Flank logs (gammaray, density, Resistivity at Bit, and Archie water saturation). (T.S. Collett, Personal Communication, November 18, 2005, Leg 204, Scientific Party, 2005) 

---