The crystal-chemical, vibrational, and optical properties of microporous aluminosilicate cancrinite have been investigated by combining electron probe microanalysis, single-crystal X-ray diffraction, infrared (IR) absorption, Raman, UV-Visible absorption, and electron spin resonance spectroscopy. The behavior of the peaks in the IR spectra was also studied during the dehydration of the sample. The analyzed sample has the following unit cell parameters (P63): a = 12.63189(14) Å, c = 5.13601(7) Å. The empirical formula, based on 12(Si + Al), is Na6.47Ca1.23K0.01[Al5.97Si6.03O24] (CO3)1.45(SO4)0.03Cl0.01·2H2O. The Al-Si framework of AB-type is formed by columns of based-shared “cancrinite” (CAN) cages, containing Na and H2O positions located on the 3-fold axis, and channels with CO3 groups, lying in two mutually exclusive and partially occupied positions in the center of the channel, and split Na/Ca cation sites. The revealed characteristics are somewhat different in comparison with the cancrinite structural features previously described in the literature. Studied crystals change color from grayish-pink to blue after X-ray irradiation (104 Gy). The blue color of the irradiated cancrinite is caused by the formation (CO3)−● radicals in the crystals. Combining the results obtained using the selected methods will provide a better understanding of the relationships between the structural, chemical, and optical-physical properties of microporous aluminosilicates.

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Abstract The Norilsk-Talnakh ore district in the northwestern Siberian platform contains globally unique reserves of Cu-Ni-sulfides with Pt and, especially, Pd. The Oktyabrsk deposit, which is one of the largest in the district, is spatially and genetically associated with the Kharaelakh mafic-ultramafic intrusion and its exceptionally large metamorphic and metasomatic aureoles. In this study, we employed in situ laser ablation-inductively coupled plasma-mass spectrometry U-Pb isotope dating of apatite, titanite, garnet, and perovskite that cocrystallize with disseminated sulfides within the aureole of metasomatic and contact metamorphic rocks. The calculated isotopic ages for apatite (257.3 ± 4.5 and 248.9 ± 5.1 Ma), titanite (248.6 ± 6.8 and 249.1 ± 2.9 Ma), garnet (260.0 ± 11.0 Ma), and perovskite (247.3 ± 8.2 Ma), though with large uncertainties, indicate that sulfide mineralization within metasomatic and contact-metamorphic rocks is coeval with the emplacement of the Kharaelakh intrusion. These isotopic dates are in complete agreement with the published isotope dilution-thermal ionization mass spectrometry U-Pb zircon ages for the Norilsk intrusions and, at the same time, notably older than available Re-Os isochron ages of sulfides. The latter ages have been long interpreted as evidence for a prolonged duration of magmatic ore-forming processes; however, our data narrow their life span. Trace elements in titanite and garnet allow distinguishing late- and postmagmatic grains, which show indistinguishable U-Pb isotope ages.