Archaean supracrustal complexes, known in the Fennoscandian (Baltic) Shield, are described and discussed by analysing the time sections 3.1-2.9, 2.9-2.75 and 2.75-2.65 Ga. Data on granitoid complexes, interrelated in time and space, and evidence for Archaean metamorphic events are classified and presented briefly. Fragments of ophiolitic and eclogitic associations have been found in Archaean rocks in the Shield. The first evidence of continental crust in the Shield is from Meso-Archaean time (3.5-3.1 Ga); isolated microcontinents, such as Vodlozero, lisalmi and North Finland, have been identified. New continental crust was mainly generated in the 2.9-2.65 Ga interval. The geodynamic settings in which the continental crust was formed in the Meso-and Neoarchaean included subduction (ensialic and ensimatic), accretion and collisional mechanisms. The continental and oceanic crust were affected by mantle plumes.

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Multidisciplinary studies of zircons, rock-forming minerals and the whole-rock composition of granulite samples from the Bug Granulite–Gneiss Complex, Ukraine (including ion microprobe REE analysis, secondary ion mass spectrometry (SIMS) U–Pb and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) Lu–Hf analysis of zircons from a single sample) have revealed three major stages in the geological evolution of the complex. (i) At 3.66 Ga, a mafic intrusion contaminated with felsic rocks formed, as evidenced by 3.74 Ga zircon xenocrysts with inclusions of plagioclase, K-feldspar and quartz. (ii) At 3.59–3.55 Ga, high-temperature and high- to moderate-pressure granulite-facies metamorphism accompanied by migmatization and deformation resulted in the formation of mafic granulites. (iii) At 2.1–2.0 Ga, metamorphic overprinting occurred, and metatrachybasaltic dykes intruded at approximately 2.0 Ga. The metamorphic mineral assemblages recorded in the dykes formed at temperatures similar to those of the 3.59–3.55 Ga metamorphism but at pressures 2–3 kbar lower. This metamorphism disturbed the Sm–Nd whole-rock system, altered the Hf isotope system of the older zircons and resulted in Pb loss in small zircon grains. This complex event history recorded in zircons from a single rock corresponds to major stages of the geological evolution of both the Dniester–Bug Province and the entire Ukrainian Shield.

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