Results of U-Pb dating of zicon from kimberlite pipes and diamond placers of the siberian platform
M.N. Goloburdina1, S.A. Grakhanov1, N.V. Rodionov1, A.I. Dak2
1A.P. Karpinsky All-Russian Geological Research Institute, St. Petersburg, Russia
2PJSC “ALROSA”,Mirny, Russian
Keywords: Siberian Platform, kimberlite, diamond placers, zircon, U–Pb age, SIMS, SHRIMP, trace elements, primary source of diamonds, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic
Abstract
This paper presents the results of studies of zircon grains from kimberlite and carbonatite bodies, as well as from ancient and modern diamond placers of the Lena–Anabar subprovince of the Siberian Diamond Province. The research includes U–Pb zircon dating and the determination of trace and rare earth element concentrations using the SHRIMP-IIe secondary ion mass spectrometer. The study covered kimberlite primary bodies of different ages, Late Jurassic carbonatite breccias, all diamond placers of the Anabar, Kuonamka, and Prilensky regions, as well as placer occurrences in the Primorsky, Lower Olenek, Middle Olenek, Muno-Tyung, and Daldyn-Alakit diamondiferous regions. In association with diamonds, zircon grains yielded Jurassic, Triassic, Permian, Late Devonian-Early Carboniferous, and Silurian-Early Devonian ages, which are consistent with the ages of known primary sources. New data indicate a broader age range of Triassic productive volcanism. Analysis of all diamond placers showed that approximately 79% of them were formed from Triassic primary sources.
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