669 § Corresponding author e-mail address: felixvkaminsky@aol.com The Canadian Mineralogist Vol. 51, pp. 669-688 (2013) DOI : 10.3749/canmin.51.5.669 CARBONATITIC INCLUSIONS IN DEEP MANTLE DIAMOND FROM JUINA, BRAZIL: NEW MINERALS IN THE CARBONATE-HALIDE ASSOCIATION FELIX V. KAMINSKY § KM Diamond Exploration Ltd., 2446 Shadbolt Lane, West Vancouver, British Columbia V7S 3J1, Canada RICHARD WIRTH AND ANJA SCHREIBER Dept. 3.3 Chemistry and Physics of Earth Materials, GeoForschungsZentrum Potsdam, Potsdam D14473, Germany ABSTRACT Eleven new minerals were identified in deep mantle primary carbonatitic association as inclusions in diamond from the Juina area, Mato Grosso, Brazil. Specifically, two carbonates [magnesite and eitelite Na 2 Mg(CO 3 ) 2 ], two phosphates [mixed- anion phosphate Na 4 Mg 3 (PO 4 ) 2 (P 2 O 7 ), Fe-diphosphate Fe 2 Fe 5 (P 2 O 7 ) 4 ], two fluorides [oskarssonite AlF 3 and Ba-rich fluoride (Ba,Sr)AlF 5 ], three sulfides [pentlandite (Fe,Ni) 9 S 8 , violarite FeNi 2 S 4 , and millerite NiS], hematite, and metallic Ni-iron were detected; the two phosphates and Ba-rich fluoride are observed in the natural environment for the first time. The mineral compositions of the analyzed inclusions are variable, even at a nanometer scale, which indicates variability in the source media during the formation of diamond. Volatiles, represented in the form of porosity, played a significant role in this process. Most mineral phases contain volatile elements, as well. Carbonatitic inclusions most likely originated from high-density fluid (HDF) microinclusions encapsulated in diamond during its growth. During the ascent of diamond, HDF inclusions underwent disintegration in composition and crystallized as polymineralic inclusions. Formation of diamond in the studied case took place in a carbonatitic, carbonate-halide-phosphate-fluoride medium, which was enriched in volatiles and acted as an open system during diamond formation. Keywords: diamond, inclusions, lower mantle, Deep Mantle, carbonatite, volatiles, carbonates, magnesite, breunnerite, eitelite, halides, phosphates, Na 4 Mg 3 (PO 4 ) 2 (P 2 O 7 ), Fe 2 Fe 5 (P 2 O 7 ) 4 , fluorides, oskarssonite, (Ba,Sr)AlF 5 , pentlandite, violarite, mil- lerite, hematite, metallic Ni-iron, TEM, Juina, Brazil INTRODUCTION Over the last two decades, lower-mantle minerals have been discovered among inclusions in diamond (e.g., Kaminsky 2012 and references therein). One of the major areas with lower-mantle diamonds is the Juina area in the state of Mato Grosso in Brazil (Kaminsky et al. 2001, 2009a). The use of transmission electron microscopy (TEM) along with electron diffraction, electron energy-loss spectroscopy (EELS), analytical electron microscopy (AEM), and other methods allowed us to discover a carbonatitic association of minerals Volume 51 October 2013 Part 5