Native sulfur at the seafloor: Composition and origin - Archive ouverte HAL
Article Dans Une Revue Chemical Geology Année : 2024

Native sulfur at the seafloor: Composition and origin

Vesselin M. Dekov
  • Fonction : Auteur
Andrea Koschinsky
  • Fonction : Auteur
Toshiro Yamanaka
  • Fonction : Auteur
Sven Petersen
  • Fonction : Auteur
Sophie A.L. Paul
  • Fonction : Auteur
Charlotte Kleint
  • Fonction : Auteur
Ewan Pelleter
Gert J. de Lange
  • Fonction : Auteur
Victoria Kürzinger
  • Fonction : Auteur
Dieter Garbe-Schönberg
  • Fonction : Auteur
Monika Ilieva
  • Fonction : Auteur
Yves Fouquet
  • Fonction : Auteur
Olivier Rouxel

Résumé

Mineralogy, geochemistry and sulfur (S) isotope composition of native sulfur (S0) precipitated at intraoceanic and intracontinental back-arc rift, submarine and subaerial volcanic arc, sediment and sediment-free mid-ocean ridge, hot spot, accretionary wedge, and submarine and continental cave settings were investigated with a main goal to understand the mode of formation of all the types of native S at the modern seafloor. Native S occurs as various depositional forms: chimneys, colloform flows, liquid ponds, slabs; fills in cavities and pore space of the sediment, vesicles and cracks in volcanic rocks; cements and coats the sediment; stains the conduits or fills in pores of the sulfide chimneys; forms fine-grained layers within the sediment; coats the walls, stalactites and stalagmites in the caves. Mineralogically, the native S from the seafloor is pure rhombic S0 with negligible impurities of metal sulfides, aluminosilicates, and carbonates inferred from the chemistry data. Mineral interrelations and S isotope data suggest that native S from different geologic settings has different origin. In the sulfide chimneys and mounds at the mid-ocean ridges, native S appears to be a result of oxidative alteration of primary pyrrhotite. The native S from back-arc rifts, volcanic arcs and hot spots can be a result of either disproportionation of magmatic SO2 (δ34S < 0 ‰), or synproportionation of magmatic SO2 and H2S (δ34S > 0 ‰). The native S from the sediments in anoxic brine-filled deeps (accretionary wedge setting) is a result of bacterial sulfate reduction and consequent sulfide (δ34S < 0 ‰) oxidation. The native S coating the cave walls and forms also has a bacterial origin (δ34S < 0 ‰).
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Dates et versions

hal-04731658 , version 1 (11-10-2024)

Identifiants

Citer

Vesselin M. Dekov, Andrea Koschinsky, Toshiro Yamanaka, Sven Petersen, Sophie A.L. Paul, et al.. Native sulfur at the seafloor: Composition and origin. Chemical Geology, 2024, 668, 122295 (18p.). ⟨10.1016/j.chemgeo.2024.122295⟩. ⟨hal-04731658⟩
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