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Mineralogy, chemical composition and structure of the MIR Mound, TAG Hydrothermal Field
Author(s) -
Stepanova T. V.,
Krasnov S. G.,
Cherkashev G. A.
Publication year - 1996
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/96gl02145
Subject(s) - pyrite , sphalerite , marcasite , geology , chalcopyrite , bornite , greigite , geochemistry , volcanogenic massive sulfide ore deposit , mineralogy , hydrothermal circulation , galena , sulfide minerals , sulfide , materials science , copper , metallurgy , seismology
The study of samples collected from the surface of the MIR mound (TAG Hydrothermal Field) by video‐controlled hydraulic grab allowed identification of a number of mineralogical types. These include pyrite‐chalcopyrite (Py‐Cp), bornite‐chalcopyrite‐opaline (Bn‐Cp‐Op) and sphalerite‐opaline (Sp‐Op) sulfide chimneys, massive sulfides composed of pyrite (Py), chalcopyrite‐pyrite (Cp‐Py), marcasite‐pyrite‐opaline (Mc‐Py‐Op), sphalerite‐pyrite‐opaline (Sp‐Py‐Op) and sphalerite‐chalcopyrite‐pyrite‐opaline (Sp‐Cp‐Py‐Op), as well as siliceous and Fe‐Mn oxide hydrothermal deposits. Most of the minor elements (Ag, Au, Cd, Ga, Hg, Sb and Pb) are associated with Zn‐rich massive sulfides, Co Bi, Pb, and As with Ferich ones, while Cu‐rich sulfides are depleted of trace metals. Cu‐enriched assemblages are concentrated in the northern part, Zn‐enriched in the center, and siliceous rocks in the south of the MIR mound. According to paragenetic relations, the development of the mound started with the formation of quartz (originally opaline) rocks and dendritic assemblages of melnikovite‐pyrite, followed by deposition of chalcopyrite and recrystallization of primary pyrite, subsequent generation of sphalerite‐rich assemblages and final deposition of opaline rocks. The late renewal of hydrothermal activity led to local formation of Cu‐rich chimneys enriched in Au, Ag, Hg and Pb probably due to their remobilization from inner parts of the deposit.