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GALLIUM‐BEARING SPHALERITE IN A METAL‐SULFIDE NODULE OF THE QINGZHEN (EH3) CHONDRITE
Author(s) -
Rambaldi E.R.,
Rajan R.S.,
Housley R.M.,
Wang D.
Publication year - 1986
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1986.tb01223.x
Subject(s) - troilite , sphalerite , kamacite , sulfide , nickel sulfide , chalcopyrite , mineralogy , geology , chemistry , chondrite , metallurgy , materials science , meteorite , pyrite , copper , physics , astronomy
The Qingzhen (EH3) chondrite contains a population of spheroidal metal‐sulfide nodules, which display textural evidence of reheating and melting. Evidence of metal sulfuration is also present, suggesting replacement of metal by sulfide during melting. This process has led to the nucleation of perryite along metal‐sulfide interfaces. Gallium‐bearing sphalerite and a Cu‐sulfide of composition intermediate between chalcopyrite and cubanite occur as inclusions within the metal of some nodules. Other phases present are: kamacite, troilite, Ga‐free sphalerite, niningerite, perryite, schreibersite, oldhamite, Cr‐sulfide (minerals A and B), djerfisherite, SiO 2 , albite and enstatite. The Ga‐bearing sphalerite may have formed by injection of molten sulfide droplets into the metal followed by subsolidus diffusion of Ga from the metal into the sulfide. The latter may occur because of Ga supersaturation in the metal during progressive sulfuration and its decreased affinity for the metal phase during cooling below the taenite‐kamacite transition point.