FN Archimer Export Format PT J TI Helium transport in sediment pore fluids of the Congo-Angola margin BT AF CHADUTEAU, Carine JEAN-BAPTISTE, Philippe FOURRE, Elise CHARLOU, Jean-Luc DONVAL, Jean-Pierre AS 1:1,2;2:1;3:1;4:2;5:2; FF 1:PDG-DOP-DCB-GM-LGM;2:;3:;4:PDG-DOP-DCB-GM-LGM;5:PDG-DOP-DCB-GM-LGM; C1 UVSQ, CNRS, Lab CEA, IPSL,LSCE, F-91191 Gif Sur Yvette, France. Inst Francais Rech Exploitat Mer, Lab Geochim & Metallogenie, F-29280 Plouzane, France. C2 UNIV VERSAILLES, FRANCE IFREMER, FRANCE SI BREST SE PDG-DOP-DCB-GM-LGM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-univ-france IF 2.626 TC 12 UR https://archimer.ifremer.fr/doc/2009/publication-6112.pdf LA English DT Article DE ;Zaire Angola margin;Sediment;Regab;Pore fluids;Pockmark;Helium AB During the ZaiRov2 cruise of the ZaiAngo project (1998-2000) on the passive Congo-Angola margin, several gravity cores were analyzed for helium isotopic composition of sedimentary pore waters in two cold fluid seepage zones: the Astrid slide area and the Regab giant pockmark. Gas concentration and isotopic composition are presented along with thermal data in terms of the origin and circulation of fluids. Helium isotope data lie on a mixing line between bottom seawater and an almost pure radiogenic. Helium and temperature vertical profiles are well described by the classic diffusion-advection equation. On the basis of He profiles, we estimate the advection rate on the rim of the pockmark between 1.2 and 2.3 mm/a. The He flux derived for a pure diffusive regime (2.4 x 10(-8) mol/m(2)/a) can favorably be compared to literature data and contrasts with the flux computed close to the pockmark center (1.9 x 10(-7) mol/m(2)/a). Helium depth profiles turned to be more sensitive to advection rate than temperature profiles are. PY 2009 SO Geochemistry Geophysics Geosystems SN 1525-2027 PU American Geophysical Union VL 10 IS 1 UT 000262377800001 BP 1 EP 12 DI 10.1029/2007GC001897 ID 6112 ER EF