Rare earth element concentrations and geochemistry of carbonate minerals from the Logatchev Hydrothermal Field and the Gakkel Ridge ...

• Main Authors: Eickmann, Benjamin, Bach, Wolfgang, Rosner, Martin, Peckmann, Jörn
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2009
• Subjects: Television-Grab; Remote operated vehicle; Dredge, pipe; M60/3; ARK-XVII/2; Meteor 1986; Polarstern; Center for Marine Environmental Sciences MARUM; From Mantle to Ocean Energy-, Material- and Life-cycles at Spreading Axes DERIDGE; Arctic; Mid-Atlantic Ridge; Gakkel Ridge
• Online Access: https://dx.doi.org/10.1594/pangaea.746502; https://doi.pangaea.de/10.1594/PANGAEA.746502

The ultramafic-hosted Logatchev Hydrothermal Field (LHF) at 15°N on the Mid-Atlantic Ridge and the Arctic Gakkel Ridge (GR) feature carbonate precipitates (aragonite, calcite, and dolomite) in voids and fractures within different types of host rocks. We present chemical and Sr isotopic compositions of these different carbonates to examine the conditions that led to their formation. Our data reveal that different processes have led to the precipitation of carbonates in the various settings. Seawater-like 87Sr/86Sr ratios for aragonite in serpentinites (0.70909 to 0.70917) from the LHF are similar to those of aragonite from the GR (0.70912 to 0.70917) and indicate aragonite precipitation from seawater at ambient conditions at both sites. Aragonite veins in sulfide breccias from LHF also have seawater-like Sr isotope compositions (0.70909 to 0.70915), however, their rare earth element (REE) patterns show a clear positive europium (Eu) anomaly indicative of a small (< 1%) hydrothermal contribution. In ... : Supplement to: Eickmann, Benjamin; Bach, Wolfgang; Rosner, Martin; Peckmann, Jörn (2009): Geochemical constraints on the modes of carbonate precipitation in peridotites from the Logatchev Hydrothermal Vent Field and Gakkel Ridge. Chemical Geology, 268(1-2), 97-106 ...