Geochemical, Isotopic, and SHRIMP Age Data for Precambrian Basement Rocks, Permian Volcanic Rocks, and Sedimentary Host Rocks to the Ore-bearing Intrusions, Noril'sk-Talnakh District, Siberian Russia

Petrographic, geochemical, and isotopic data have been obtained for 33 samples selected to provide constraints on contamination models for the volcanic and intrusive components of the Late Permian to Early Triassic, Siberian flood-volcanic province. Twenty-one of these samples were carried from great depth in an explosive diatreme of Triassic age, whereas 12 were collected from drill core from depths of tens to 2000 m. The studied diatreme xenoliths are: (1) fragments of the crystalline basement; and (2) fragments of a basaltic-to-rhyolitic volcanic suite. Prompted by an unexpected, Late Paleozoic, Rb-Sr isochron age for this compositionally diverse volcanic suite, a SHRIMP U-Pb zircon age of ∼270 Ma was obtained for a rhyodacite xenolith. Previously, a SHRIMP zircon U-Pb age of ∼910 Ma had been determined for a leucogranite xenolith from the crystalline basement; this sample also contains substantial amounts of inherited, Early Proterozoic and Archean zircon. The presence of this volcanic suite, only ∼20...