FN Archimer Export Format
PT J
TI Mixed carbonate-siliceous hydrothermal chimneys ahead of the Asal propagating rift (SE Afar Rift, Republic of Djibouti)
BT 
AF Moussa, Nima
   Bayon, Germain
   Dekov, V.
   Yamanaka, T.
   Shinjo, R.
   Toki, T.
   Le Gall, Bernard
   Grassineau, N.
   Langlade, Jessica
   Awaleh, M.O.
   Pelleter, Ewan
AS 1:1;2:2;3:3;4:3;5:4,5;6:5,6;7:7;8:8;9:9;10:1;11:2;
FF 1:;2:PDG-REM-GEOOCEAN-ASTRE;3:;4:;5:;6:;7:;8:;9:;10:;11:PDG-REM-GEOOCEAN-CYBER;
C1 Institut des Sciences de la Terre, Centre d’Etudes et de Recherches de Djibouti, B.P. 486, Djibouti
   Univ Brest, CNRS, Ifremer, Geo-Ocean, F-29280, Plouzané, France
   Department of Ocean Sciences, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato-ku, Tokyo, 108-8477, Japan
   Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa, 903-0213, Japan
   Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8047, Japan
   Department of Chemistry, Biology and Marine Science, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa, 903-0213, Japan
   UMR/CNRS 6538 Géosciences Océan, UBO-IUEM, Place Nicolas Copernic, 29280, Plouzané, France
   Department of Earth Sciences, Royal Holloway University of London, EGHAM Surrey, TW20 0EX, UK
   CNRS, IUEM, UMS 3113, F-29280, Plouzané, France
C2 CERD, DJIBOUTI
   IFREMER, FRANCE
   UNIV TOKYO, JAPAN
   UNIV RYUKYUS, JAPAN
   RIHN, JAPAN
   UNIV RYUKYUS, JAPAN
   UBO, FRANCE
   UNIV LONDON, UK
   CNRS, FRANCE
SI BREST
SE PDG-REM-GEOOCEAN-ASTRE
   PDG-REM-GEOOCEAN-CYBER
UM GEO-OCEAN
IN WOS Ifremer UMR
   WOS Cotutelle UMR
   copubli-france
   copubli-europe
   copubli-univ-france
   copubli-int-hors-europe
   copubli-sud
IF 2.3
TC 1
UR https://archimer.ifremer.fr/doc/00799/91132/96809.pdf
LA English
DT Article
DE ;SE Afar Rift;Hydrothermal chimneys;Isotopic analyses;Allols sites;Djibouti
AB Numerous active and fossil hydrothermal carbonate chimneys have been reported at Lake Asal and Lake Abhe, in the southeastern part of the Afar Rift (Republic of Djibouti): a tectonically and volcanically active region for the last 30 million years. In this study, we report on a detailed mineralogical and geochemical investigation of unusual hydrothermal mixed carbonate-siliceous chimneys recently discovered in the Allols area (Harralol, Haralé Awda and Sakallol), northwest of the Asal Rift. These inactive chimneys, up to 20 m high, consist of tall spires partly stained by Fe-oxides. They are located along major faults and were formed sub-aqueously when the area was occupied by a lake. Hydrothermal carbonate structures were also found in the same area. The oxygen (δ18O) and carbon (δ13C) isotopic compositions of the chimneys range from −4.5 to 25.3‰ and from −9.44 to 8.92‰, respectively, indicating mixing between magmatic and surficial waters. Their radiogenic Sr isotopic compositions (87Sr/86Sr = 0.7049–0.7056) show values typical of altered basaltic rocks. Chimneys also exhibit negative Ce anomaly suggestive of a genetic link with basalt alteration. Overall, this study suggests that lake water chemistry in the Allols area experienced major changes in the past, reflecting various contributions of mixing fluids (lake water and hydrothermal fluids), leading alternatively to deposition of carbonate chimneys and precipitation of (and/or replacement with) silica. 
PY 2023
PD JAN
SO Journal Of African Earth Sciences
SN 1464-343X
PU Elsevier BV
VL 197
UT 000882458000002
DI 10.1016/j.jafrearsci.2022.104765
ID 91132
ER

EF