Lomonosovite from Ilímaussaq intrusion, South Greenland
Karup-Møller, S.
Neues Jahrbuch für Mineralogie - Abhandlungen Band 148 Heft 1 (1983), p. 83 - 96
8 Literaturangaben
veröffentlicht: Dec 8, 1983
ArtNo. ESP154014801006, Preis: 29.00 €
Abstract
Lomonosovite from the Kvanefjeld area within the Ilímaussaq intrusion has the chemical composition (Na4.49Ca0.12Fe0.10+2)Σ5.71 (Ti1.76Nb0.10Fe0.03+3Mn0.02)Σ1.91 (Si2.00P1.00)Σ3.00O12.83. F was present in amounts less than 0.2 %. The following trace elements in ppm were recorded in two samples: Cl 460,200; Pb 30,40; Rb 220,330; S 990,360; Sn 220,230; Sr 160,430; Ta 290,40; Th <10,110; Y 44,82; Zn 220,500 and Zr 650,400. Ni <20 and Sc, Ba, Cs and Cu < 100. Lomonosovite is triclinic space group 1, and shaped as tabular crystals bound by the forms {001}, {013}, {012}, {012}, {014}, {201}, {201}, and {110}. The a axis lies in the tabular direction. One of the optical axes lies in the a-c crystallographic plane and this axis forms an angle of 74° with the a-axis. The optical normal is perpendicular to the face pairs (201) (201). The mineral is optically negative with 2V = 61-60°. It is twinned with (001) as the composition plane and the axis as the twin axis. Cleavage after (001). The cell dimensions are a = 5.393(2) Å, b = 7.121(4) Å, c= 14.420(10) Å, α = 100.02(2)°, β = 96.44(5)° and γ = 90.44(4)°. Guinier powder data, IR data and thermal data are listed.
Schlagworte
Lomonosovite • crystal geometry • optical property • thermal analysis • microprobe analysis • X-ray powder diffraction • Guinier • lattice constant • infrared spectrum • Mössbauer spectrum 57Fe • element correlation; Ilímaussaq intrusion • Greenland.