FN Archimer Export Format
PT J
TI Spatial Variations in Vent Chemistry at the Lucky Strike Hydrothermal Field, Mid Atlantic Ridge (37°N): Updates for Subseafloor Flow Geometry from the Newly Discovered Capelinhos Vent.
BT 
AF CHAVAGNAC, V.
   LELEU, T.
   FONTAINE, F.
   CANNAT, M.
   CEULENEER, G.
   CASTILLO, A.
AS 1:1;2:1;3:2,3;4:2;5:1;6:1;
FF 1:;2:;3:;4:;5:;6:;
C1 Univ Toulouse, Geosci Environm Toulouse, Toulouse, France.
   Inst Phys Globe Paris, Paris, France.
   Observ Volcanol Piton Fournaise, La Plaine Des Cafres, Reunion, France.
C2 UNIV TOULOUSE, FRANCE
   IPGP, FRANCE
   OBSERV VOLCANOL PITON FOURNAISE, FRANCE
IF 2.946
TC 20
UR https://archimer.ifremer.fr/doc/00460/57185/59146.pdf
   https://archimer.ifremer.fr/doc/00460/57185/59147.pdf
LA English
DT Article
CR MOMARSAT2013
BO Pourquoi pas ?
DE ;EMSO-Azores;Lucky Strike;hydrothermalism;hydrothermal circulation;isotope geochemistry;permeability
AB This study aims at characterizing the subseafloor architecture of the Lucky Strike hydrothermal field (LSHF) based on an extensive chemical database of the various vents. Our analysis is motivated by the discovery in 2013 of a new active high‐temperature site, named Capelinhos, approximately 1.5 km east of the LSHF. Capelinhos fluids display particular chemical features with chloride and metals (Fe, Mn) concentrations two times lower and four times higher, respectively, compared to other vent sites. Trace element partitioning over the entire chlorinity range indicates a single deep fluid source feeding all the venting sites. Applying the Si‐Cl geothermobarometer at Capelinhos, we find phase separation conditions at 435–440°C, and 370‐390 bars (2500–2800 m below seafloor (mbsf)) consistent with former estimates for the LSHF, while temperatures of fluid‐rock last equilibrium are estimated at ~400°C for Capelinhos and 350‐375°C for the other sites based on the Fe‐Mn geothermometer. We interpret these discrepancies in thermodynamic conditions beneath the sites in terms of crustal residence time which are likely related to permeability variations across the hydrothermal upflow zone. We propose that conductive cooling of the up flowing fluids from the phase separation zone to the seafloor, beneath the main field vent sites, lowers the T conditions of last fluid‐rock equilibrium, enabling ~65% of Fe mobilized in the reaction zone to be stored. In comparison, Capelinhos fluids are transported more rapidly from the reaction zone to the seafloor along a high‐angle fracture system. The fluids venting at Capelinhos are more representative of the deeper part of the hydrothermal reaction zone. 
PY 2018
PD NOV
SO Geochemistry Geophysics Geosystems
SN 1525-2027
PU Amer Geophysical Union
VL 19
IS 11
UT 000452727800019
BP 4444
EP 4458
DI 10.1029/2018GC007765
ID 57185
ER

EF