FN Archimer Export Format PT J TI Pockmark formation and evolution in deep water Nigeria: Rapid hydrate growth versus slow hydrate dissolution BT AF SULTAN, Nabil BOHRMANN, G. RUFFINE, Livio PAPE, T. RIBOULOT, Vincent COLLIAT, J. -L. DE PRUNELE, Alexis DENNIELOU, Bernard GARZIGLIA, Sebastien HIMMLER, Tobias MARSSET, Tania PETERS, C. A. RABIU, A. WEI, J. AS 1:1;2:2;3:1;4:2;5:1;6:3;7:1;8:1;9:1;10:1,2;11:1;12:2;13:4;14:2; FF 1:PDG-REM-GM-LES;2:;3:PDG-REM-GM-LGM;4:;5:PDG-REM-GM-LES;6:;7:PDG-REM-GM-LGM;8:PDG-REM-GM-LES;9:PDG-REM-GM-LES;10:PDG-REM-GM-LGM;11:PDG-REM-GM-LES;12:;13:;14:; C1 IFREMER, REM GM LES, Plouzane, France. Univ Bremen, MARUM Ctr Marine Environm Sci, D-28359 Bremen, Germany. TOTAL, Pau, France. NIOMR, Victoria Isl, Nigeria. C2 IFREMER, FRANCE UNIV BREMEN MARUM, GERMANY TOTAL, FRANCE NIOMR, NIGERIA SI BREST SE PDG-REM-GM-LES PDG-REM-GM-LGM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-europe copubli-int-hors-europe copubli-sud TC 62 UR https://archimer.ifremer.fr/doc/00188/29913/28373.pdf LA English DT Article CR GUINECO-MEBO BO Pourquoi pas ? AB In previous works, it has been suggested that dissolution of gas hydrate can be responsible for pockmark formation and evolution in deep water Nigeria. It was shown that those pockmarks which are at different stages of maturation are characterized by a common internal architecture associated to gas hydrate dynamics. New results obtained by drilling into gas hydrate-bearing sediments with the MeBo seafloor drill rig in concert with geotechnical in situ measurements and pore water analyses indicate that pockmark formation and evolution in the study area are mainly controlled by rapid hydrate growth opposed to slow hydrate dissolution. On one hand, positive temperature anomalies, free gas trapped in shallow microfractures near the seafloor and coexistence of free gas and gas hydrate indicate rapid hydrate growth. On the other hand, slow hydrate dissolution is evident by low methane concentrations and almost constant sulfate values 2 m above the Gas Hydrate Occurrence Zone. PY 2014 PD APR SO Journal Of Geophysical Research-solid Earth SN 0148-0027 PU Amer Geophysical Union VL 119 IS 4 UT 000337688600007 BP 2679 EP 2694 DI 10.1002/2013JB010546 ID 29913 ER EF