There are two 300-500-km long belts of Palaeoproterozoic layered intrusions: the Northern (Kola) Belt and the Southern (Fenno-Karelian) Belt in the Baltic (Fennoscandian) Shield. New U-Pb (TIMS) ages and radiogenic isotopic (Nd-Sr-He) data have been determined for mafic-ultramafic Cu-Ni-Ti-Cr and PGEbearing layered intrusions of the Kola Belt. U-Pb ages on zircon and baddeleyite for gabbronorite and anorthosite from the Fedorovo-Pansky, Monchepluton and Main Ridge (Monchetundra and Chunatundra), Mt. Generalskaya intrusions and gabbronorite and dykes from the Imandra lopolith of the Kola Belt define a time interval of more than 130 million years, from ca. 2.52 Ga to 2.39 Ga. At least four intrusive phases have been distinguished: three PGE-bearing, and one barren. This spread of ages is wider than that for intrusions of the Fenno-Karelian Belt which clusters at 2.44 Ga. Nd isotopic values for the Northern Belt range from -1.1 to -2.4, implying an enriched mantle "EM-1 type" reservoir for these layered intrusions. Initial Sr isotopic data for the rocks of the intrusions are radiogenic relative to bulk mantle, with I Sr values from 0.703 to 0.704. 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. 1) extends for a few kilometres into Sweden (Tornio intrusion), and for several tens of kilometres into the Russian Karelia (Olanga complex). Together the intrusions make up the Southern, or Fenno-Karelian Belt -FKB (Mitrofanov et al., 1997).In the northeast of the province, the Northern, or Kola Belt (KB) strikes northwestwards for about 500 km (Fig.1). It includes more than ten isolated layered mafic-ultramafic bodies that are mostly ore-bearing (Mitrofanov et al., 1997). The central part of the Kola Belt has been suggested to be part of a triple junction typical of intraplate rifting (Pirajno, 2007), and is occupied by the Monchegorsk Layered Complex with a fairly complete range of ore types (Cr, Cu, Ni, Co, Ti, V, Pt, Pd, Rh). The western and eastern arms of the triple junction are composed of large anorthositetroctolite (Main Ridge, Pyrshin, Kolvitsa) intrusions (Fig. 1). The most typical PGE-bearing layered pyroxenite-norite-gabbro-anorthosite intrusions of the Kola Belt (Mt. General'skaya, Monchegorsk Layered Complex...

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The Central Indian Tectonic Zone (CITZ) marks the suture zone where the North and South Indian cratonic blocks amalgamated to form the Greater Indian Landmass (GIL). It consists of three broad domains from west to east: the central CITZ occupying the central region of mainland India juxtaposed between two mobile belts, namely the Sausar Mobile Belt (SMB) in the south and the Mahakoshal Mobile Belt (MMB) in the north; the Chotanagpur Granite Gneiss Complex (CGGC) lying east of the main CITZ; and the easternmost Shillong Plateau Gneissic Complex (SPGC). The studied granites are from the Bathani Volcano Sedimentary sequence (BVSs) from the northern margin of the CGGC. These are high-K, calc-alkaline, I-type granites related to arc magmatism and are interpreted to have formed by partial melting of an igneous source at upper-crustal depths. The granitic magma underwent extensive fractional crystallization of plagioclase, biotite, K-feldspar and ilmenite during emplacement. The U–Pb (ID-TIMS) zircon emplacement age is c. 1.7–1.6 Ga for these granites. This episode of magmatism can be correlated to the global event of the Nuna supercontinent assembly also reported from the MMB of the central CITZ. We infer that the BVSs is the eastern continuation of the MMB of the central CITZ.