Timing and duration of Palaeoproterozoic events producing ore-bearing layered intrusions of the Baltic Shield: Metallogenic, petrological and geodynamic implications

T. Bayanova, J. Ludden, F. Mitrofanov

Research output: Chapter in Book/Report/Conference proceedingChapter

48 Citations (Scopus)

Abstract

There are two 300-500 km long belts of Palaeoproterozoic layered intrusions in the Baltic (Fennoscandian) Shield; the Northern (Kola) Belt and the Southern (Fenno-Karelian) Belt. New U-Pb (TIMS) ages and radiogenic isotopic (Nd-Sr-He) data have been determined for mafic-ultramafic Cu-Ni-Ti-Cr and PGE-bearing layered intrusions of the Kola Belt. U-Pb zircon and baddeleyite data from gabbronorite and anorthosite bodies of the Fedorovo-Pansky, Monchepluton, Main Ridge (Monchetundra and Chunatundra) and Mt Generalskaya intrusions, and from gabbronorite intrusions and dykes associated with the Imandra lopolith, yield ages from c. 2.52-2.39 Ga. The age range of 130 Ma recorded in the Kola Belt samples, associated with at least four intrusive phases (three PGE-bearing and one barren), is significantly greater than that for intrusions of the Southern (Fenno-Karelian) Belt which clusters at 2.44 Ga. Nd isotopic values for the Kola Belt range from 21.1 to 22.4 and indicate an enriched mantle 'EM-1 type' reservoir for these layered intrusions. Initial Sr isotopic data for the Kola intrusions are radiogenic relative to bulk mantle, with I Sr values from 0.703 to 0.704, but geochemical data and 4He/ 3He isotopic ratios of various minerals record a significant contribution from a mantle source rather than simply crustal melting. The geological and geochronological data indicate that in the eastern part of the Baltic Shield, mafic-ultramafic intrusive magmatism was active over a protracted period and was related to plume magmatism associated with continental breakup that also involved the Superior and Wyoming provinces.

Original languageEnglish
Title of host publicationPalaeoproterozoic Supercontinents and Global Evolution
PublisherGeological Society of London
Pages165-198
Number of pages34
ISBN (Electronic)9781862392830
DOIs
Publication statusPublished - 1 Jan 2009

Publication series

NameGeological Society Special Publication
PublisherGeological Society of London
Volume323
ISSN (Print)0305-8719
ISSN (Electronic)2041-4927

ASJC Scopus subject areas

  • Water Science and Technology
  • Ocean Engineering
  • Geology

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