RV SONNE CRUISE REPORT SO143 - TECFLUX - I - 1999 : TECTONICALLY-INDUCED MATERIAL FLUXES, HONOLULU - ASTORIA - SAN DIEGO, JUNE 29 - SEPTEMBER 6 , 1999

• Other Authors: Bohrmann, Gerhard, Linke, Peter, Suess, Erwin, Pfannkuche, Olaf
• Format: Report
• Language: English
• Published: GEOMAR Forschungszentrum für Marine Geowissenschaften 2000
• Subjects: Canada; Methane hydrate
• Online Access: https://oceanrep.geomar.de/id/eprint/25904/; https://oceanrep.geomar.de/id/eprint/25904/1/geomar%20report%2093.pdf; https://doi.org/10.3289/GEOMAR_REP_93_2000

The TECFLUX program (= TECtonically induced FLUXes) addresses geophysical, biogeochemical, and hydrographic processes associated with fluid venting from the Cascadia continental margin, specifically the processes resulting from the methane hydrate dynamics at Hydrate Ridge. An international group of scientists from institutions in Germany, the USA, Canada, and Japan (Table 1 and list of Participating Institutions) established a long-term research program based on the initial discovery in 1996 of methane hydrate exposures. At this margin site mixed methane-sulfide hydrates and carbonates form a pavement along the crest of the ridge at water depths between 600-1000 m. Vent fields from which methane-charged, low-salinity fluids containing sulfide, ammonia, 4He, and isotopically light C02 escape, are associated with these exposures. The fluid emissions characterize a newly recognized mechanism of dewatering at convergent margins. However, the rates of discharge, the fluctuations and frequency of pulses, as well as the mechanisms responsible for the modulations of flow are totally unknown. Also immediate and intriguing questions concerning the composition, depth distribution, interlayering with sediment, and physical properties of these near-surface gas hydrates were to be addressed during SO Cruise 143.