Vol.:(0123456789) 1 3 Contributions to Mineralogy and Petrology (2019) 174:8 https://doi.org/10.1007/s00410-018-1540-8 ORIGINAL PAPER Djerfsherite in kimberlites and their xenoliths: implications for kimberlite melt evolution Adam Abersteiner 1  · Vadim S. Kamenetsky 1  · Karsten Goemann 2  · Alexander V. Golovin 3,4  · Igor S. Sharygin 3  · Andrea Giuliani 5,6  · Thomas Rodemann 2  · Zdislav V. Spetsius 7  · Maya Kamenetsky 1 Received: 12 June 2018 / Accepted: 4 December 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2019 Abstract Djerfsherite (K 6 (Fe,Ni,Cu) 25 S 26 Cl) occurs as an accessory phase in the groundmass of many kimberlites, kimberlite- hosted mantle xenoliths, and as a daughter inclusion phase in diamonds and kimberlitic minerals. Djerfsherite typically occurs as replacement of pre-existing Fe–Ni–Cu sulphides (i.e. pyrrhotite, pentlandite and chalcopyrite), but can also occur as individual grains, or as poikilitic phase in the groundmass of kimberlites. In this study, we present new con- straints on the origin and genesis of djerfsherite in kimberlites and their entrained xenoliths. Djerfsherite has extremely heterogeneous compositions in terms of Fe, Ni and Cu ratios. However, there appears to be no distinct compositional range of djerfsherite indicative of a particular setting (i.e. kimberlites, xenoliths or diamonds), rather this compositional diversity refects the composition of the host kimberlite melt and/or interacting metasomatic medium. In addition, djer- fsherite may contain K and Cl contents less than the ideal formula unit. Raman spectroscopy and electron backscatter difraction (EBSD) revealed that these K–Cl poor sulphides still maintain the same djerfsherite crystal structure. Two potential mechanisms for djerfsherite formation are considered: (1) replacement of pre-existing Fe–Ni–Cu sulphides by djerfsherite, which is attributed to precursor sulphides reacting with metasomatic K–Cl bearing melts/fuids in the mantle or the transporting kimberlite melt; (2) direct crystallisation of djerfsherite from the kimberlite melt in groundmass or due to kimberlite melt infltration into xenoliths. The occurrence of djerfsherite in kimberlites and its mantle cargo from localities worldwide provides strong evidence that the metasomatising/infltrating kimberlite melt/fuid was enriched in K and Cl. We suggest that kimberlites originated from melts that were more enriched in alkalis and halogens relative to their whole-rock compositions. Keywords Djerfsherite · Kimberlite · Sulphides · Metasomatism · Potassium · Chlorine · Diamond Communicated by Chris Ballhaus. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00410-018-1540-8) contains supplementary material, which is available to authorised users. * Adam Abersteiner adam.abersteiner@utas.edu.au 1 School of Physical Sciences, University of Tasmania, Hobart, TAS 7001, Australia 2 Central Science Laboratory, University of Tasmania, Hobart, TAS 7001, Australia 3 Sоbоlеv Institute of Geology and Mineralogy, Siberian Вrаnсh Russian Academy of Sciences, Koptyuga Pr. 3, Novosibirsk 630090, Russian Federation 4 Novosibirsk State University, Pirogova 2, Novosibirsk 630090, Russian Federation 5 KiDs (Kimberlites and Diamonds), School of Earth Sciences, The University of Melbourne, Parkville, VIC 3010, Australia 6 ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS) and GEMOC, Department of Earth and Planetary Sciences, Macquarie University, North Ryde, NSW 2109, Australia 7 Geo-Scientifc Investigation Enterprise, ALROSA PJSC, Mirny, Yakutia, Russia