FN Archimer Export Format
PT J
TI Authigenic carbonates related to active seepage of methane-rich hot brines at the Cheops mud volcano, Menes caldera (Nile deep-sea fan, eastern Mediterranean Sea)
BT 
AF PIERRE, Catherine
   BAYON, Germain
   BLANC-VALLERON, Marie-Madeleine
   MASCLE, Jean
   DUPRE, Stephanie
AS 1:1;2:2;3:3;4:4;5:2;
FF 1:;2:PDG-REM-GM-LGM;3:;4:;5:PDG-REM-GM-LGG;
C1 Univ Paris 06, LOCEAN, UMR 7159, F-75252 Paris 05, France.
   IFREMER, F-29280 Plouzane, France.
   CR2P, UMR 7207, F-75005 Paris, France.
   Observ Oceanol, F-06235 Villefranche Sur Mer, France.
C2 UNIV PARIS 06, FRANCE
   IFREMER, FRANCE
   UNIV PARIS 06, FRANCE
   UNIV PARIS 06, FRANCE
SI PARIS
   BREST
SE PDG-REM-GM-LGM
   PDG-REM-GM-LGG
IN WOS Ifremer jusqu'en 2018
   copubli-france
   copubli-univ-france
IF 2.122
TC 32
TU Centre national de la recherche scientifique
   Institut de recherche pour le développement
   Muséum national d'histoire naturelle
   Université Pierre et Marie Curie
   École pratique des hautes études
UR https://archimer.ifremer.fr/doc/00186/29735/28189.pdf
LA English
DT Article
CR NAUTINIL
BO L'Atalante
AB On the passive margin of the Nile deep-sea fan, the active Cheops mud volcano (MV; ca. 1,500 m diameter, ~20–30 m above seafloor, 3,010–3,020 m water depth) comprises a crater lake with hot (up to ca. 42 °C) methane-rich muddy brines in places overflowing down the MV flanks. During the Medeco2 cruise in fall 2007, ROV dives enabled detailed sampling of the brine fluid, bottom lake sediments at ca. 450 m lake depth, sub-surface sediments from the MV flanks, and carbonate crusts at the MV foot. Based on mineralogical, elemental and stable isotope analyses, this study aims at exploring the origin of the brine fluid and the key biogeochemical processes controlling the formation of these deep-sea authigenic carbonates. In addition to their patchy occurrence in crusts outcropping at the seafloor, authigenic carbonates occur as small concretions disseminated within sub-seafloor sediments, as well as in the bottom sediments and muddy brine of the crater lake. Aragonite and Mg-calcite dominate in the carbonate crusts and in sub-seafloor concretions at the MV foot, whereas Mg-calcite, dolomite and ankerite dominate in the muddy brine lake and in sub-seafloor concretions near the crater rim. The carbonate crusts and sub-seafloor concretions at the MV foot precipitated in isotopic equilibrium with bottom seawater temperature; their low δ13C values (–42.6 to –24.5‰) indicate that anaerobic oxidation of methane was the main driver of carbonate precipitation. By contrast, carbonates from the muddy lake brine, bottom lake concretions and crater rim concretions display much higher δ13C (up to –5.2‰) and low δ18O values (down to –2.8‰); this is consistent with their formation in warm fluids of deep origin characterized by 13C-rich CO2 and, as confirmed by independent evidence, slightly higher heavy rare earth element signatures, the main driver of carbonate precipitation being methanogenesis. Moreover, the benthic activity within the seafloor sediment enhances aerobic oxidation of methane and of sulphide that promotes carbonate dissolution and gypsum precipitation. These findings imply that the coupling of carbon and sulphur microbial reactions represents the major link for the transfer of elements and for carbon isotope fractionation between fluids and authigenic minerals. A new challenge awaiting future studies in cold seep environments is to expand this work to oxidized and reduced sulphur authigenic minerals.
PY 2014
PD JUL
SO Geo-marine Letters
SN 0276-0460
PU Springer
VL 34
IS 2-3
UT 000336392800012
BP 253
EP 267
DI 10.1007/s00367-014-0362-6
ID 29735
ER

EF