115 research outputs found
Mineralogical and geochemical features of the Manus Basin hydrothermal sulfide ores, Bismarck Sea
Paragenetic mineral assemblages have been established based on
mineralogical, chemical, and isotope (S, Pb) studies, and the sequence
of deposition has been defined in hydrothennal sulfide structures in a
typical back-arc basin. The ores in the Manus basin have a prominent
Zn specialization (sphalerite, wĂĽrtzite, and fe-sphalerite). An association
of Fe-spbalerite and galena with Ag sulfosalts is noted that is not
characteristic of typical midocean ridge hydrothennal systems. The
average 34S in the sulfide minerals is 3.5%o, which corresponds to the
medium-temperature sphalerite stage in hydrothermal mineral fonnation.
It is suggested that the metal source is located in the relatively acid
rocks of the island-arc tholeiitic series and possibly in sediments
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