Skaergaardite, PdCu, a new platinum-group intermetallic mineral from the Skaergaard intrusion, Greenland

被引:39
作者
Rudashevsky, NS
McDonald, AM
Cabri, LJ
Nielsen, TFD
Stanley, CJ
Kretzer, YL
Rudashevsky, VN
机构
[1] Ctr New Technol, St Petersburg 195427, Russia
[2] Laurentian Univ, Dept Earth Sci, Sudbury, ON, Canada
[3] Cabri Consulting Inc, Ottawa, ON K1S 5P5, Canada
[4] CANMET MMSL, Ottawa, ON K1A 0G1, Canada
[5] Geol Survey Denmark & Greenland, DK-1350 Copenhagen K, Denmark
[6] Nat Hist Museum, London SW7 5BD, England
关键词
skaergaardite; Pd-Cu intermetallic; new mineral species; CsCl-type structure; platinum-group elements; hydroseparation; Skaergaard intrusion; Greenland; Duluth intrusion; Minnesota;
D O I
10.1180/0026461046840208
中图分类号
P57 [矿物学];
学科分类号
070901 ;
摘要
Skaergaardite, PdCu, is a new mineral discovered in the Skaergaard intrusion, Kangerdlugssuaq area, East Greenland. It occurs in a tholeitiic gabbro associated with plagioclase, clinopyroxene, orthopyroxene, ilmenite, titanian magnetite, fayalite and accessory chlorite-group minerals, ferrosaponite, a member of the annite-phlogopite series, hornblende, actinolite, epidote, calcite, ankerite, apatite and baddeleyite. The mineral is found in composite microglobules composed of bornite, chalcocite, digenite, chalcopyrite, with rare cobalt pentlandite, cobaltoan pentlandite, sphalerite, keithconnite, vasilite, zvyagintsevite, (Cu,Pd,Au) and Pt-Fe-Cu-Pd alloys, unnamed PdCu3, (Pd,Cu,Sn), Au3Cu and PdAuCu. Skaergaardite Occurs as droplets, equant grains with rounded outlines, subhedral to euhedral crystals and as irregular grains that vary in size from 2 to 75 mum, averaging 22 mum. It is steel grey with a bronze tint. has a black streak, a metallic lustre and is sectile. Neither cleavage nor fracture was observed. The mineral has a micro-indentation hardness of VHN25 = 257. It is isotropic, non-pleochroic and exhibits neither discernible internal reflections nor evidence of twinning. Skaergaardite varies from bright creamy white (associated with bornite and chalcopyrite) to bright white (associated with digenite and chalcocite). Reflectance values in air (and in oil) are: 58.65 (47.4) at 470 nm, 62.6 (51.1) at 546 nm, 64.1 (52.8) at 589 nm and 65.25 (53.95) at 650 nm. The average of 311 electron-microprobe analyses gives: I'd 58.94, Pt 1.12 AU 2.23, Cu 29.84, Fe 3.85, Zn 1.46, Sn 1.08, Te 0.28 and Pb 0.39, total 99.19 wt.%, corresponding to (Pd0.967Au0.020Pt0.010)(Sigma0.997)(Cu0.820Fe0.120Zn0.039Sn0.016Te0.004Pb0.003)(Sigma1.002). The mineral is cubic, space group Pm3m, a = 3.0014(2) Angstrom, V = six strongest lines in the X-ray powder-diffraction pattern 27.0378 Angstrom(3), Z = 1. D-calc is 10.64 g/cm(3). The six strongest lines in the X-ray powder-diffraction pattern [d in Angstrom(l)(hkl)] are: 2.122(100)(110), 1.5000(20)(200), 1.2254(50)(211), 0.9491(20)(310), 0.8666(10)(222), 0.8021(70)(321). The mineral has the CsCl-type structure. It is believed to be isostructural with wairauite (CoFe), synthetic CuZn (beta-brass) and is structurally related to hongshiite (PtCu). Skaergaardite developed from a disordered Pd-Cu-rich metal alloy melt that had exsolved from an earlier Cu-(Fe) sulphide melt. Ordering of Pd and Cu (beginning at T approximate to 600degreesC) results in development of the CsCl structure from a disordered face-centred Cubic structure.
引用
收藏
页码:615 / 632
页数:18
相关论文
共 27 条
[1]   The triple group and the Platinova gold and palladium reefs in the Skaergaard intrusion: Stratigraphic and petrographic relations [J].
Andersen, JCO ;
Rasmussen, H ;
Nielsen, TFD ;
Ronsbo, JG .
ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS, 1998, 93 (04) :488-509
[2]  
Baker HOH, 1992, ALLOY PHASE DIAGRAMS
[3]  
BAYLISS P, 2001, MINERAL POWDER DIFFR
[4]   A GOLD-BEARING HORIZON IN THE SKAERGAARD INTRUSION, EAST-GREENLAND [J].
BIRD, DK ;
BROOKS, CK ;
GANNICOTT, RA ;
TURNER, PA .
ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS, 1991, 86 (05) :1083-1092
[5]   Fermi surface incommensurate nestings and phase equilibria in Cu-Pd alloys [J].
Bruno, E ;
Ginatempo, B ;
Giuliano, ES .
PHYSICAL REVIEW B, 2001, 63 (17)
[6]  
CABRI L.J., 2002, Canadian Institute of Mining, Metallurgy and Petroleum, CIM Special, V54, P13
[7]  
CABRI L. J., 2004, P CANADIAN MINERAL P, P189
[8]  
Challis G.A., 1964, Mineralogical magazine, V33, P942
[9]  
Ellis W.C., 1941, T AM SOC MET, V29, P415
[10]  
Irvine T. N., 1992, CARNEGIE I WASH YR B, V91, P91