Synthesis of Nickeloan Djerfisherites and the Origin of Potassic Sulphides at the Frank Smith Mine

  1. F.R. Boyd and
  2. Henry O.A. Meyer
  1. D.B. Clarke

Published Online: 19 MAR 2013

DOI: 10.1029/SP016p0300

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

The Mantle Sample: Inclusion in Kimberlites and Other Volcanics

How to Cite

Clarke, D.B. (1979) Synthesis of Nickeloan Djerfisherites and the Origin of Potassic Sulphides at the Frank Smith Mine, in The Mantle Sample: Inclusion in Kimberlites and Other Volcanics (eds F.R. Boyd and H. O.A. Meyer), American Geophysical Union, Washington, D.C.. doi: 10.1029/SP016p0300

Author Information

  1. Department of Geology, Dalhousie University, Halifax, N.S., Canada B3H 3J5

Publication History

  1. Published Online: 19 MAR 2013
  2. Published Print: 1 JAN 1979

ISBN Information

Print ISBN: 9780875902135

Online ISBN: 9781118664858

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Keywords:

  • Alkali metal-transition element;
  • Clinopyroxene-ilmenite nodule;
  • Frank Smith sulphides;
  • Nickeloan djerfisherites;
  • X-ray powder diffraction techniques

Summary

Many alkali metal-transition element chalcogenides have been synthesized, but only three potassic sulphides are known to occur as minerals. One of these, a nickeliferous djerfisherite, occurs in a clinopyroxene-ilmenite nodule from the Frank Smith mine. To investigate its conditions of formation, a range of djerfisherites with 100 Fe/(Fe+Ni) from 100–41 has been synthesized at temperatures of 649°, 452° and 352°C at one-atmosphere pressure. The experimental work shows the ability of nickeliferous djerfisherites to form in the subsolidus by a reaction between pre-existing sulphides and a potassium-rich vapour phase. Textural evidence from the Frank Smith occurrence points to the formation of nickeliferous djerfisherite by this mechanism at temperatures less than 610°C where pentlandite is stable. Another, chlorine-free potassium-iron-nickel-copper sulphide has been discovered in the Frank Smith nodule, and has probably formed by the same process as the nickeliferous djerfisherite. It is proposed that the term ‘djerfisherite' be redefined as the nickel- and copper-free iron end-member with a formula approximating K6Fe26−xS26Cl1, and that essentially Fe-Ni solid solutions be called nickeloan djerfisherite (Ni < Fe), and Fe-Cu solid solutions be termed cuprian djerfisherite (Cu < Fe).