The Pobeda hydrothermal cluster was discovered during cruise 37 of Professor Logachev R/V (JSC PMGRE) in 2014–2015 during work in the Russian Exploration Area in the axial zone of the Mid-Atlantic Ridge. The cluster is located between 17°07.45′ and 17°08.7′ N on the eastern side of the rift valley, in the depth range of 1950–3100 m. The cluster is confined to the gabbro-peridotite complex, folded by modern carbonate, ore-bearing, and metalliferous sediments, and consists of the Pobeda-1, Pobeda-2 ore fields and the Pobeda-3 ore occurrence. The Pobeda cluster shows signs of modern hydrothermal activity. Sediments were sampled from the vessel using a box sampler and a TV grab. The background sediments are represented by homogeneous coccolithic foraminiferous silt of beige and brownish-beige color with an admixture of sandy fraction. The work is devoted studying of ore minerals of the surface horizon of ore-bearing sediments of the Pobeda hydrothermal cluster using optical microscopy, scanning electron microscopy, and X-ray microanalysis. It was found that ore minerals in ore-bearing sediments are represented by fragments of copper and iron sulfides (isocubanite, chalcopyrite, pyrite), newly formed iron hydroxides and atacamite. In addition, barite and edaphogenic material, sometimes with sulfide inclusions, are present. The location of the presumed active hydrothermal source in the area of the Pobeda-3 ore occurrence is clarified on the basis of hydrophysical data. The character of distribution of the minerals studied depending on the location relative to active hydrothermal vents is described. Also, a decrease in the Cu/Fe ratio in the chemical composition of copper and iron sulfides is observed when moving away from the vents. In the surface horizon of column 37L245g, an unidentified phase of composition Cu3.57–4.22Fe1.71–2.19S4.99–5.31 with inclusions of lamellae of chalcopyrite is established.

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Hydrothermal Minerals Formed by Deposition from the Plume in the Pobeda Ore Cluster Sediments

  • Anastasia D. Lyutkevich,
  • Irina F. Gablina

摘要

The Pobeda hydrothermal cluster was discovered during cruise 37 of Professor Logachev R/V (JSC PMGRE) in 2014–2015 during work in the Russian Exploration Area in the axial zone of the Mid-Atlantic Ridge. The cluster is located between 17°07.45′ and 17°08.7′ N on the eastern side of the rift valley, in the depth range of 1950–3100 m. The cluster is confined to the gabbro-peridotite complex, folded by modern carbonate, ore-bearing, and metalliferous sediments, and consists of the Pobeda-1, Pobeda-2 ore fields and the Pobeda-3 ore occurrence. The Pobeda cluster shows signs of modern hydrothermal activity. Sediments were sampled from the vessel using a box sampler and a TV grab. The background sediments are represented by homogeneous coccolithic foraminiferous silt of beige and brownish-beige color with an admixture of sandy fraction. The work is devoted studying of ore minerals of the surface horizon of ore-bearing sediments of the Pobeda hydrothermal cluster using optical microscopy, scanning electron microscopy, and X-ray microanalysis. It was found that ore minerals in ore-bearing sediments are represented by fragments of copper and iron sulfides (isocubanite, chalcopyrite, pyrite), newly formed iron hydroxides and atacamite. In addition, barite and edaphogenic material, sometimes with sulfide inclusions, are present. The location of the presumed active hydrothermal source in the area of the Pobeda-3 ore occurrence is clarified on the basis of hydrophysical data. The character of distribution of the minerals studied depending on the location relative to active hydrothermal vents is described. Also, a decrease in the Cu/Fe ratio in the chemical composition of copper and iron sulfides is observed when moving away from the vents. In the surface horizon of column 37L245g, an unidentified phase of composition Cu3.57–4.22Fe1.71–2.19S4.99–5.31 with inclusions of lamellae of chalcopyrite is established.