Tectonic, stratigraphic, and geochemical comparisons between ca. 2500–2440Ma mafic igneous events in the Canadian and Fennoscandian Shields

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

“…1). In Finland, these geological complexes have been widely studied (Alapieti et al, 1990;Huhma et al, 1990;Vogel et al, 1998;Hanski et al, 2001), and the data were summarized by M. Iljina and E. Hanski (2005). Only a few publications on similar Russian complexes of the Baltic Shield have been written or translated into English (Papunen & Gorbunov et al, 1985;Balashov et al, 1993;Bayanova & Balashov, 1995;Amelin et al, 1995;Mitrofanov et al, 1997;Mitrofanov & Bayanova, 1999; Chashchin et al, 2002;Schissel et al, 2002;Mitrofanov et al, 2005).…”

“…Geochemical data and 4 He / 3 He isotopic ratios of the minerals reflect a significant contribution from a mantle source rather than the influence of crustal processes during emplacement. 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.Key words: geochronology, isotopes, Palaeoproterozoic, layered PGE-bearing intrusions, BalticShield.There are about twenty Palaeoproterozoic layered mafic-ultramafic bodies in Finland, most of which occur in a roughly eastwest-trending, 300-km long belt known as the Tornio-NäränkävaaraBelt (Alapieti et al, 1990;Vogel et al, 1998;Iljina & Hanski, 2005). The belt ( Fig.…”

Geology and metallogenic potential of the northwesternmost Norrbotten Province around Altevatn in Troms, northern Norway

“…The northeastern part of the Shield is dominated by Neoarchaean rocks, which give way southwestwards to the Palaeoproterozoic (2.0-1.8 Ga) Sveco fennian Province. The early geological evolution is character ised by break-up of the Neoarchaean Kenorland supercontinent between 2.5 and 2.1 Ga (e.g., Vogel et al, 1998;Daly et al, 2006), associated with widespread mafic and ultramafic magmatism, development of rift basins, high-grade metamorphism and extensional deformation, eventually resulting in ocean-floor spreading between c. 2.1 and 2.0 Ga (Berthelsen & Marker, 1986). Closure of these ocean basins resulted in arc-arc, arc-continent and continent-continent collisions between 1.95 and 1.87 Ga (Berthelsen & Marker, 1986;Daly et al, 2006).…”

The geochemistry and petrogenesis of the Paleoproterozoic du Chef dyke swarm, Québec, Canada

“…The trace element signatures of these three suites are common in igneous rocks formed in (Vogel et al 1998); or, (3) the contamination of mantle melts by continental crust during fractionation in deep crustal magma chambers (e.g., Nelson et al 1990). …”