Contact metamorphic and metasomatic processes at the Kharaelakh Intrusion, Oktyabrsk Deposit, Norilsk-Talnakh ore district; application of laser ablation-inductively coupled plasma-mass spectrometry dating of perovskite, apatite, garnet, and titanite
Contact metamorphic and metasomatic processes at the Kharaelakh Intrusion, Oktyabrsk Deposit, Norilsk-Talnakh ore district; application of laser ablation-inductively coupled plasma-mass spectrometry dating of perovskite, apatite, garnet, and titanite
Economic Geology and the Bulletin of the Society of Economic Geologists (July 2020) 115 (6): 1213-1226
- absolute age
- apatite
- Asia
- Commonwealth of Independent States
- contact metamorphism
- copper ores
- copper sulfides
- dates
- garnet group
- giant deposits
- ICP mass spectra
- inductively coupled plasma methods
- intrusions
- isochrons
- Krasnoyarsk Russian Federation
- laser ablation
- laser methods
- Lower Triassic
- mass spectra
- Mesozoic
- metal ores
- metals
- metamorphism
- metasomatism
- methods
- mineral deposits, genesis
- mineralization
- nesosilicates
- nickel ores
- Norilsk region
- Norilsk Russian Federation
- orthosilicates
- oxides
- perovskite
- phosphates
- platinum group
- Re/Os
- Russian Federation
- Siberian Platform
- silicates
- spectra
- spectroscopy
- sulfides
- Taymyr Dolgan-Nenets Russian Federation
- titanite
- titanite group
- trace elements
- Triassic
- U/Pb
- zircon
- zircon group
- Kharayelakh Intrusion
- Oktyabrskoye Deposit
- Norilsk-Talnakh mining district
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+ or -4.5 and 248.9+ or -5.1 Ma), titanite (248.6+ or -6.8 and 249.1+ or -2.9 Ma), garnet (260.0+ or -11.0 Ma), and perovskite (247.3+ or -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.