TY - CHAP
T1 - Timing and duration of Palaeoproterozoic events producing ore-bearing layered intrusions of the Baltic Shield
T2 - Metallogenic, petrological and geodynamic implications
AU - Bayanova, T.
AU - Ludden, J.
AU - Mitrofanov, F.
PY - 2009/1/1
Y1 - 2009/1/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=75149122492&partnerID=8YFLogxK
U2 - 10.1144/SP323.8
DO - 10.1144/SP323.8
M3 - Chapter
AN - SCOPUS:75149122492
T3 - Geological Society Special Publication
SP - 165
EP - 198
BT - Palaeoproterozoic Supercontinents and Global Evolution
PB - Geological Society of London
ER -