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The Archean-Proterozoic transition marks a time of fundamental geologic, biologic, and atmospheric changes to the Earth system, including oxygenation of the atmosphere (termed the Great Oxygenation Event; GOE), and the emergence of continents above sea level. The impacts of the GOE on Earth’s surface environment are imprinted on the geologic record, including the disappearance of mass-independent fractionation of sulfur isotopes (S-MIF). Temporally overlapping geologic and geochemical observations (e.g. a change in oxygen isotope ratio of sediments and an increase in subaerial volcanism) imply the widespread subaerial emergence of continents was coeval with atmospheric oxygenation. Here we present triple sulfur isotope ratios in pyrite and oxygen isotope ratios in garnet and zircon in a global suite of Archean and Proterozoic granitoids derived from the partial melting of sedimentary protoliths. These crustal melts record an increase in average garnet and zircon δ18O from 7.2‰ before 2.3 Ga to 10.0‰ post-2.3 Ga. Pre-2.3 Ga granitoids show small S-MIF signatures with Δ33S ranging from −0.29‰ to 0.13‰, whereas post-2.3 Ga granitoids record S-MDF (i.e. Δ33S = 0‰). The combination of sulfur and oxygen isotope signatures in the same sample with zircon U-Pb geochronology provides new insights on a potential causal link between the emergence of continents and Paleoproterozoic atmospheric oxygenation.

The Azov Domain occurs as a part of a larger Mesoarchean (3.2-3.0 Ga) craton, fragments of which are preserved in the eastern part of the Ukrainian Shield and as a block of the Kursk Magnetic Anomaly (KMA). In the Neoarchean-Palaeoproterozoic time, it was fragmented into several tectonic blocks: Vovcha, Remivka, Huliaipole, Bilotserkivka, and Saltych. The northern part of the Huliaipole Block is composed of tonalite-trondhjemite-granodiorite (TTG) rock association, that hosts the Kosivtsevo greenstone structure. It is composed of metamorphosed rocks of the jaspilite-komatiite-tholeiite association (the Kosivtsevo unit), which corresponds to the Sura Suite of the Konka Series of the Middle Dnieper Domain. The Neoarchean-Paleoproterozoic formations are represented by volcano-sedimentary rocks of the Huliaipole Suite and granitoids of the Dobropillya and Anadol complexes. Granitoids of the Dobropillya complex host numerous pyroxenite, gneiss, and plagioclase granite xenoliths. The U-Pb zircon age of granitoids of the Dobropillya Complex is 2040 Ma and inherited zircon has an age up to 3400 Ma. Small intrusions of two-feldspar granites of the Anadol Complex are widespread in the Ternuvate structure. Their U-Pb monazite age is 2190 Ma. In the central part of the Huliaipole Block, the NW-striking Huliaipole syncline (3.5 × 9 km) occurs. This structure is composed of volcano-sedimentary rocks of the Huliaipole Suite, which unconformably overlie Archean TTG. Felsic and intermediate metavolcanics are confined mainly to ferruginous quartzites of the middle Subsuites. To a limited extent, meta-andesites and felsic metavolcanics are also found in the lower and upper Huliaipole Subsuites. Zircons from meta-andesites and felsic metavolcanics of the Huliaipole Suite are very heterogeneous, indicating their crustal derivation. The U-Pb age of zircon populations from metadacite of the Huliaipole Suite was determined using the LA-ICP-MS method at 3085-2850 and 3700-3360 Ma. In addition, the age of the two crystals exceeded 3800 Ma. According to geological and geochronological data, the Huliaipole Block, 30 × 50 km in size, is composed of rocks and relicts of the Hadean, Archean, and Palaeoproterozoic eons. The oldest nucleoid of the Azov Domain.

LA-ICP-MS method was applied to investigate U-Pb and Lu-Hf isotope systematics of zircon crystals from charnockitic gneiss and biotite-garnet-hypersthene enderbite that occur in the lower reaches of the Yatran river (Yatran block of the Bouh river area). According to the obtained isotope data, charnockitic gneiss hosts three zircon populations. The oldest one is represented by three crystals that have isotope age between 3125 and 3300 Ma, and εHf values between –2.3 and –7.5. The next population is well-defined, it has an age of 2038±25 Ma and large variations of Hf isotope composition: 176Hf/177Hf — from 0.28122 to 0.28261, εHf — from –9.3 до 4.6. However, the ages of most of the analyzed zircons spread along the concordia between 2300 and 2800 Ma. All zircons in this population have a similar Hf isotope composition 176Hf/177Hf = 0.28072 to 0.28092, which does not depend on the age. It is characteristic that the oldest (with preserved U-Pb isotope systematics) crystals have positive or slightly negative εHf values. Most of the U-Pb isotope analyses of zircons from enderbite fall on the discordia line that has an upper interception age of 2029 ± 18 Ma. A small number of discordant grains have 207Pb/206Pb ages up to 2500 Ma. Hafnium isotope composition in zircons from enderbite varies widely: 176Hf/177Hf = 0.28131 to 0.28151, and εHf from –6.2 to 1.8.

Results of U-Pb dating of zircons from the Middle Devonian sandstones of the Mykolaivka Suite, taken from the junction zone between the Azov Domain of the Ukrainian Shield and Donets basin, are reported. The rocks are taken from a drill core and they occur beneath a 210 m sequence of mafic and ultramafic volcanic rocks that belong to the Antonivka (D2-3) and Mykolaivka (D2) suites. In total, 28 U-Pb isotope analyses were performed. The predominant population (18 grains) of zircons yielded a concordant age of 2075±9 Ma (MSWD = 0.64). The second largest population consists of zircon crystals with concordant to nearly concordant ages ranging from 3130 to 2830 Ma. These results indicate a local origin for the detrital zircons. The occurrence of coarse-grained terrigenous sediments, derived from local rock sources, indicates significant erosion of the Precambrian basement that might have been caused by differential vertical movements during the Middle Devonian period. In the Donets basin, rifting and uplift started ca. 10 Myr before that of other parts of the Prypyat-Dnieper-Donets Paleorift.

The Dizi Series is exposed within the Southern Slope zone of the Greater Caucasus, in the core of the Svaneti anticlinorium. It is mainly composed of terrigenous, volcanogenic and carbonate rocks faunistically dated from the Devonian to the Triassic inclusive. Regional and contact metamorphism of the Dizi Series rocks was studied. It is stated that the degree of regional metamorphism corresponds to the chlorite-sericite subfacies of the greenschist facies, occurring at a temperature of 300–350°C and a pressure of 1.5–2.3 kbar. As a result of the action of the Middle Jurassic intrusive rock bodies, the regionally metamorphosed rocks of the Dizi Series underwent contact metamorphism. Three zones of contact metamorphism were distinguished corresponding to albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels subfacies. Contact metamorphism took place at a significantly higher temperature and lower pressure than the preceding regional metamorphism. The maximum temperature of the contact metamorphism reached ≈ 570°С, while pressure varied within the range of ≈ 0.3–0.8 kbar. The evolution of rock associations of regional and contact metamorphism of the Dizi Series was studied. The fields of facies and subfacies of regional and contact metamorphism are shown in the Ps-T diagram. Three age populations of zircons were identified using U-Pb LA-ICP-MS dating of the diorite-porphyrite intrusion in the Dizi Series: Zrn1 (ca. 2200 Ma) and Zrn2 (458 ± 29 Ma) that were captured by the diorite-porphyrite magma from the ancient magmatic and metamorphic rocks of the crystalline basement, and Zrn3 (166.5 ± 4.6 Ma) that corresponds to the age of diorite-porphyrite crystallization.

The West Azov iron district corresponds to the Korsak synclinorium or block in which iron deposits of the Kamyana Mohyla belt (Pavlivka, Novoukrainka, and Serhiivka areas), Kuksungur, and Korsak Mohyla are located. The iron– bearing units are confined to the metamorphosed volcanogenic–sedimentary rocks of the Satchky Formation of the Central Azov Group, while rocks of the Temryuk Formation form the base of the section. The group is intruded by numerous dykes of pink microcline granites and pegmatites up to 15 to 20 m in thickness. The basement for the group consists of Archean plagioclase granitoids hosting xenoliths of gneisses, crystalline schists, and amphibolites. The iron ores of the Korsak block are characterized by the same rock association and mineral assemblage as those in the Mangush and Orikhovo–Pavlohrad structures. We have conducted geochronological study of metaterrigenous rocks of the Temryuk Formation of the Novoukrainka (Kamyana Mohyla) iron deposit. The iron deposit extends along the western limb of the Korsak synclinorium for ca. 20 km. The prevailing strike of the iron deposit is NW 350°. Metamorphic rocks form separate bodies (lenses) that are continuous along the strike for 1200–1500 m with a maximum thickness of 120– 140 m. Ferruginous quartzites are represented by banded iron formation with interlayers of biotite and biotite–amphibole gneisses (Sachky Formation). Micaceous (biotite, garnet–biotite) quartzites occur in the lower part of the section, where they are interbedded with biotite, muscovite–biotite–sillimanite, biotite–amphibole, and, rarely, pyroxene–garnet–biotite gneisses and schists (Temryuk Formation). Fifty–eight grains of detrital zircon from micaceous quartzite of the Temryuk Formation were dated by LA–ICP–MS. Four crystals were dated at 3.2–3.23 Ga, three more grains have an age of 3.08– 3.11 Ga, thirty–two crystals yielded an age of 2.9–2.97 Ga, fifteen crystals had an age of 2.82–2.87 Ga, and, finally, four grains were dated at 2.76–2.78 Ga. According to the obtained data, metasedimentary rocks of the Central Azov Group, bearing iron–rich units in the Korsak synclinorium of the West Azov area were deposited on the basement with the Mesoarchean (2.9–3.1 Ga) Tonalites–Trondjemites–Granites (TTG). Archean granites with ages of 2.82–2.87 and 2.76– 2.78 Ga as well as the remnants of older TTGs provided a minor contribution from the provenance. The Central Azov Group was intruded by the 2.2 Ga Na–K–rich granites. On the Mesoarchean Azov craton, volcanogenic–sedimentary rocks of the Huliaipole Formation in the Huliaipole brachysyncline and the Vovchansk unit in the Orekhiv–Pavlohrad structure were formed during the same time interval. Deposition of this volcanogenic–sedimentary succession with thick Banded Iron Formations (BIFs) is possibly related to submarine volcanism and marine transgression.

The stratigraphic relationships of meta-terrigenous rocks of the Kryvyi Rih Series belonging to the Kryvyi Rih-Kremenchuk structure with metasediments of similar composition belonging to the upper part of the greenstone belt section (the Bilozerka Series) in the Middle Dnieper Domain remain unexplored. The adjacent “strip-like” Vysokopillya, Skhidno- Hannivska and Zhovta Richka structures are of particular interest; in these structures, metasediments and ferruginoussiliceous rocks overlie metabasites of the Mesoarchean greenstone belts. The Vysokopillya greenstone belt (GB), which is adjacent to the Likhmanivka syncline of the Kryvyi Rih structure, is a steep-bedding monocline. The northern part of the belt comprises a thick homogeneous meta-tholeiite sequence (the Sura Suite). The Chertomlyk Suite is located higher in the stratigraphic section and includes meta-andesites with subordinate rhyodacites and tholeiitic basalts. They form the southern part of this structure. Subvolcanic rhyolite-dacite bodies (the Solenivka Suite) occur as crosscutting intrusions and dykes. The middle and southern parts of the Vysokopillya GB consist of a heterogeneous mass of orthogneisses and paragneisses, which developed after sedimentary (graywackes, sub-graywackes and melawackes) and volcanic (tuff sandstones, lava breccias, meta-dacites and meta-andesites with a subordinate amount of meta-tholeiites) rocks were deposited. Graywackes host thin beds of quartz-magnetite quartzites and thick (up to 100 m) beds of quartzmagnetite- cummingtonite shales with garnet. We applied LА-ICP-MS for U-Pb dating of 102 detrital zircons from biotite-quartz meta-sandstones and determined their Hf isotope compositions. Among them, four crystals have 207Pb/206Pb age over 3400 (up to 3800) Ma. A single zircon crystal was dated at 2930 Ma. The remaining 97 crystals have ages in the range of 3000-3360 Ma, with distinct peaks at 3065 (15 grains), 3185 (21 grains), 3260 (16 grains), and 3320 Ma (22 grains). Hafnium isotope composition varies over a wide range. The oldest grain dated at 3800 Ma, has eHf = –0,8, whereas the next two younger grains have positive eHf values (+1,2 at 3645 Ma, and +2,2 at 3535 Ma). Crystals dated at ca. 3320 Ma demonstrate wide variations in eHf — from +1,8 to -6,1; those dated at ca. 3260 Ma — from +4,5 to –2,5, those dated at ca. 3185 Ma — from +3,3 to –4,3, and those dated at ca. 3065 Ma — from +6,2 to –3,9. According to the obtained data, metasedimentary rocks of the Vysokopillya GB started to accumulate in the Neoarchean. The same age was established for the metamorphosed sedimentary rocks of the Skhidno-Hannivska and Krasnoyarsk-Alferivka structures, as well as for the Bilozerka Series of the Bilozerka GB. Thus, sedimentary rocks in these structures were formed during the denudation of the Mesoarchaean craton. The source rocks were predominantly represented by the TTG of the Sura complex (3.1-2.96 Ga). For the first time, a significant number (38 grains) of Paleoarchean (3.3 Ga) detrital zircons were discovered in the Middle Dnieper Domain, which indicates the presence of Paleoarchean rocks in the denudation area. Data on Hf isotope systematics indicate the possible presence of Hadean (older than 4.0 Ga) material.

The LA-ICP-MS method was applied to investigate U-Pb and Lu-Hf isotope systematics of zircon crystals from charnockitoids that crop out in the open pits near Chausove village, Pervomaisk district. The association of enderbite gneisses, mafic and ultramafic (pyroxenite) granulites and vein bodies of pink biotite granites occur in the open pits. Enderbites are rather heterogeneous, and their composition varies from leucocratic quartzite-like rocks to enderbite-diorite. The Pervomaisk open pit is located within charnockite massif. Our data indicates that the association of enderbites and charnockites crystallised at 2850-2760 Ma from juvenile material (Hf isotope composition in zircons from enderbite-diorite is 176Hf/177Hf = 0.280915 ± 12, εHf2850 = +2; from leucocratic charnockite 176Hf/177Hf = 0.280875 ± 12, εHf2760 = –1; and from charnockite 176Hf/177Hf = 0.280875 ± 12, εHf2760 = –1). These rocks represented the newly formed Meso-Neoarchean crust, in contrast to the reworked older continental crust. This association has experienced a significant transformation in Paleoproterozoic. The last stage of transformation was accompanied by crystallisation of a new generation of zircon and formation of monazite at 2.04-2.06 Ga.

A total of 4344 magmatic U-Pb ages in the range 2300 to 800 Ma have been compiled from the Great Proterozoic Accretionary Orogen along the margin of the Columbia / Nuna supercontinent and from the subsequent Grenvillian collisional orogens forming the core of Rodinia. The age data are derived from Laurentia (North America and Greenland, n = 1212), Baltica (NE Europe, n = 1922), Amazonia (central South America, n = 625), Kalahari (southern Africa and Dronning Maud Land in East Antarctica, n = 386), and western Australia (n = 199). Laurentia, Baltica, and Amazonia (and possibly other cratons) most likely formed a ca. 10 000-km-long external active continental margin of Columbia from its assembly at ca. 1800 Ma until its dispersal at ca. 1260 Ma, after which all cratons studied were involved in the Rodinia-forming Grenvillian orogeny. However, the magmatic record is not smooth and even but highly irregular, with marked peaks and troughs, both for individual cratons and the combined data set. Magmatic peaks typically range in duration from a few tens of million years up to around hundred million years, with intervening troughs of comparable length. Some magmatic peaks are observed on multiple cratons, either by coincidence or because of paleogeographic proximity and common tectonic setting, while others are not. The best overall correlation, 0.617, is observed between Baltica and Amazonia, consistent with (but not definitive proof of) their being close neighbours in a SAMBA-like configuration at least in Columbia, and perhaps having shared the same peri-Columbian subduction system for a considerable time. Correlation factors between Laurentia and Baltica, or Laurentia and Amazonia, are below 0.14. Comparison between the Grenville Province in northeastern Laurentia and the Sveconorwegian Province in southwestern Fennoscandia (Baltica) shows some striking similarities, especially in the Mesoproterozoic, but also exhibits differences in the timing of events, especially during the final Grenville-Sveconorwegian collision, when the Sveconorwegian evolution seems to lag behind by some tens of million years. Between the other cratons, the evolution before and during the final Grenvillian collision is also largely diachronous. After 900 Ma, magmatic activity had ceased in all areas investigated, attesting to the position of most of them within the stable interior of Rodinia. publishedVersion

The Devonian magmatic association of the Eastern Azov region, which is part of the Pripyat-Dnieper-Donetsk rift zone, was studied. The association includes gabbroids, peridotites, pyroxenites, and lamprophyre dikes of the Pokrovo-Kireevsky massif (PKM) and picrites, picrobasalts and basalts of the Anton-Taramskaya suite (ATS). The clinopyroxenes of different generations from the micaceous PCM gabbro and the alkaline ATS picrite were studied. It was obtained the information on the mantle source composition and the evolution of melts, who determined the close spatial-temporal location of kimberlites, basites, ultramafic rocks, including alkaline ones, in the Eastern Azov region. Clinopyroxenes from micaceous gabbro are composed of Cpx 1 (Mg# = 0.87–0.88) or С px 2 (Mg# = 0.80–0.81) cores and Cpx 3 external zones (Mg# = 0.70–0.76). Clinopyroxenes in alkaline picrite are composed of С px 2 cores (Mg # = 0.80–0.84) and external Cpx 3 zones (Mg# = 0.71–0.78). The multielement spectra of clinopyroxenes are generally dome-shaped in nature, with enrichment with LREE, depletion of Ba, Nb, TREE, Zr-Hf negative anomaly, a negative Sr-anomaly appears in Cpx 2 and Cpx 3 also. The resulting compositions of the model melt for С px 2 from the micaceous gabbro are very close to the composition of this gabbro, and the compositions of the model melt for Cpx 2 from the alkaline picrite coincide with those of this picrite. The high Mg# value and concentrations of Cr in Cpx 1 cores indicate that the earliest weakly differentiated composition close to the primary could serve as the equilibrium melt. The presence in the Cpx 1 geochemical spectra of a negative Zr-Hf anomaly at Zr PM 0.8) melts, which formed picrobasalts and lamprophyres. The geochemical features of the early Cpx 1 cores compared with the geochemistry of clinopyroxenes from ilmenite-containing mantle metasomatites are consistent with the assumption that carbonated ilmenite-containing peridotites, possibly also phlogopite-containing (PIC), are the source of ultrahigh-Ti primary melts for the Eastern Azov lamprophyres.

We present the U-Pb geochronology and Hf isotope analysis of detrital zircons from the Ediacaran/Cambrian sediments of Podillya and south Volyn in western Ukraine, supplemented by the bulk rock XRD mineralogy of the host rocks. Such a combined analytical approach allows for identifying the source areas supplying detritus to sediments and for constraining an age of deposition. Our provenance analysis is based on fourteen samples collected from six exposures, mostly in the valley of the Dniester river. 84 mudstone samples were also examined by the XRD method. U-Pb dating of detrital zircons yielded two sets of maximum depositional ages: 578–546 Ma and 547–523 Ma, for the Mohyliv-Podilsky and Kanyliv Series, respectively. This suggests that the Ediacaran-Cambrian boundary in Podillya coincides with a major erosional gap, with a major change in provenance, and the disappearance of the Ediacaran fauna at the base of the Kanyliv Series, with implications for the stratigraphy and paleogeography of the entire East European Platform. Zircon U-Pb age spectra from the lower part of the Mohyliv-Podilsky Series include a large quantity of 2.2 to 1.9 Ga grains that reveal predominantly negative to nearly chondritic ɛHf values, jointly suggesting detritus supply from the crystalline basement of Sarmatia. Both U-Pb and mineralogical data also indicate a major contribution of volcanic detritus from the Volyn flood basalts. The younger Nagoryany rocks yielded zircon age spectra with peaks at c. 1.80 and 1.49 Ga, implying a shift of the catchment area to Fennoscandia. Above an erosional gap, the zircon age spectra in the Kanyliv and Baltic Series are dominated by peaks at 560–535 Ma. These data and ɛHf values ranging from negative to chondritic and juvenile suggest, in line with the mineralogical data, detritus supply from a continental magmatic arc and collisional orogen. Thus, we interpret the Kanyliv Series as infill of an early Cambrian foreland basin that was established in front of the Scythides and Santacrucides orogens, overriding the SW margin of Baltica.

The paper is dedicated to the study of the Devonian magmatic association of the Eastern Azov region, which is a part of the Pripyat-Dnieper-Donets rift zone. The association includes gabbros, peridotites, pyroxenites, and lamprophyre dikes of the Pokrovo-Kireevsky massif (PKM) and picrites, picrobasalts, and basalts of the Anton-Taram Formation (ATF). Analysis of clinopyroxenes of different generations from the PKM micaceous gabbro and the ATF alkaline picrite provided insight into the mantle source of these rocks and the evolution of melts, which determined the close spatiotemporal association of kimberlites, basites, ultramafic rocks, including alkaline varieties. Clinopyroxenes from the micaceous gabbro are composed of Cpx1 (Mg # = 0.87–0.88) or Сpx2 (Mg # = 0.80–0.81) cores and Cpx3 external zones (Mg # = 0.70–0.76). Clinopyroxenes from alkaline picrite are composed of Сpx2 cores (Mg # = 0.80–0.84) and external Cpx3 zones (Mg # = 0.71–0.78). Clinopyroxenes in general have an upward concave multielement pattern, with enrichment in LREE, depletion in Ba, Nb, and HREE, Zr–Hf negative anomaly, and, additionally, negative Sr-anomaly in Cpx2 and Cpx3. The calculated equilibrium melts for Сpx2 from the micaceous gabbro are very close in composition to this gabbro, and those for Cpx2 from the alkaline picrite coincide in composition with this picrite, and in general are close to ATF picritic lavas. The high Mg# and Cr content in cores Cpx1 indicate that this mineral was derived from the earliest weakly differentiated magma close to the primary melt. The presence of a negative Zr–Hf anomaly in Cpx1 geochemical patterns at ZrPM 0.8) melts, which generated picrobasalts and lamprophyres. The geochemical similarity of the early Cpx1 cores with clinopyroxenes from ilmenite-bearing mantle metasomatites is consistent with the assumption that ultrahigh-Ti primary melts of the Eastern Azov lamprophyres were derived from carbonated ilmenite-bearing, and likely, phlogopite-bearing (PIC) peridotites.

The Dizi Series is exposed within the Southern slope zone of the Greater Caucasus that occurs as a complex geological structure, which constitutes an integral part of the Mediterranean (Alpine-Himalayan) collisional orogenic belt. It is built up of terrigenous and volcanogenic-sedimentary rocks faunistically dated from the Devonian to Triassic inclusive (Somin, 1971; Somin, Belov, 1976; Kutelia 1983). Most of them are metamorphosed under conditions of chlorite-sericite subfacies of the greenschist facies of regional metamorphism (chlorite-phengite-albite±quartz, graphite-sericite-quartz phyllites and marbleized limestones), and only a minor part represented by clay-carbonaceous, phengite-chlorite-carbonaceous and prehnite-chlorite-carbonate schists underwent anchimetamorphism (Shengelia et al., 2015). The Dizi Series is intruded by numerous magmatic bodies of gabbro-diabases, diabases, diorites, diorite-porphyries, syenites, monzo-syenites and granitoids. The age of the intrusions was defined by K-Ar method at 176-165 Ma (Dudauri, Togonidze, 1998) and by U-Pb LA-ICP-MS zircon dating at 166.5 ± 4.6 Ma (authors` unpublished data) and corresponds to the Bathonian orogeny. The Middle Jurassic intrusions caused intense contact metamorphism of the rocks of the Dizi Series resulted in the formation of various hornfelses containing andalusite, cordierite, corundum, biotite, plagioclase, potassium feldspar, clinozoisite, hornblende, cummingtonite, clinopyroxene, wollastonite and scapolite. These rocks correspond to albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels subfacies of the contact metamorphism (Javakhishvili et al., 2020). The analogues of the Dizi Series rocks have not previously been established either in the Greater Caucasus or in the neighboring regions. In our view, Paleozoic rocks similar to the Dizi Series occur under the Cretaceous and Jurassic deposits within the folded basement of the plain Crimea where they were recovered by wells. Most of these rocks, as in the Dizi Series, underwent metamorphism of chlorite subfacies of the greenschist facies and, to a lesser extent, deep epigenesis (clayey-carbonaceous, sericite-carbonaceous, actinolite-chlorite-prehnite, muscovite-albite-chlorite, epidote-actinolite-chlorite and graphite-talc-quartz schists) (Chernyak, 1969). These rocks are also intruded by Middle Jurassic igneous rocks, including gabbro-diabases, diabases, diorites, syenites, monzo-syenites, granite-porphyries, etc. (Shniukova, 2016; Shumlyanskyy, 2019). As a result of the contact metamorphism of the basement rocks, muscovite-quartz-cordierite and cordierite-quartz-feldspar micaceous hornfelses were formed. Quartz syenite yielded a K-Ar age of 158 Ma (Scherbak, 1981), while monzo-syenite was dated at 170 ± 5 Ma applying 40Ar/39Ar method (Meijers, 2010). Thus, based on the rock associations, the nature of metamorphism, the age of the metamorphic and igneous rocks, and on the spatial position of the Dizi Series and folded basement of the plain Crimea we assume that these units developed coevally in similar environment and geological conditions.Acknowledgements.This work was supported by Shota Rustaveli National Science Foundation (SRNSF) [PHDF-19-159, Regional and Contact Metamorphism of the Dizi Series].

The Archean-Proterozoic transition marks a time of fundamental geologic, biologic, and atmospheric changes to the Earth system, including oxygenation of the atmosphere (termed the Great Oxygenation Event; GOE), and the emergence of continents above sea-level. The impacts of the GOE on Earth’s surface environment are imprinted on the geologic record, including the attenuation of mass-independent fractionation of sulfur isotopes (S-MIF). Temporally overlapping geologic and geochemical observations (e.g. a change in oxygen isotope ratio of sediment melts) imply the widespread subaerial emergence of continents was coeval with atmospheric oxygenation. Here we present triple sulfur isotope ratios in pyrite and oxygen isotope ratios in garnet and zircon in a global suite of Archean and Proterozoic sediment-derived granitoids. These crustal melts record an increase in average 18O/16O isotope ratio and a disappearance of S-MIF in the Paleoproterozoic. The coupled behaviour of sulfur and oxygen isotope signatures imply a potential causal link between the emergence of continents and atmospheric oxygenation at ~2.3 Ga.

The U-Pb age of zircon populations from metadacite of the Huliaipole Suite was determined using the LA-ICP-MS method as 3085-2850 and 3700-3360 Ma. In addition, two crystals of zircon were discovered with an age of more than 3800 Ma. According to geological and geochronological data, the Huliaipole Block, 30 × 50 km in size, is composed of rocks and relicts of the Hadean, Archean, and Palaeoproterozoic eons. The oldest nucleus of the Azov Domain was probably formed from 3.97 to 3.3 Ga ago. In the Mesoarchean (3.2-3.0 Ga), it became a part of the Middle Dnieper-Azov-Kursk granite-greenstone terrane. Felsic and intermediate volcanics of the Huliaipole Suite could have formed due to the melting of the sialic crust, including rocks of the Hadean and Archean age, as a result of the underplating of basic melts during the formation of the Neoarchean to Paleoproterozoic rift structures. Методом LА-ICP-MS визначено U-Pb вік популяцій циркону з метадацитів гуляйпільської світи — 3085— 2850 і 3700—3360 млн років. Крім того, виявлено два кристали циркону віком понад 3800 млн років. Згідно з геологічними і геохронологічними даними, Гуляйпільський блок, який має розміри 30 × 50 км, складений породами і їх реліктами гадейського, архейського і палеопротерозойського еонів. Найдавнішим фундаментом Приазовського мегаблока є, ймовірно, породи нуклеарної структури, яка формувалася від 3,97 до 3,3 млрд років. У мезоархеї (3,2—3,0 млрд років) вона стала частиною Середньопридніпровсько-Приазовсько-Курського граніт-зеленокам'яного терейну. Вулканіти кислого і середнього складу гуляйпільської світи могли утворитися внаслідок плавлення порід сіалічної кори, що включала породи гадейського і архейського віку, в результаті андерплейтингу базитових розплавів під час формування неоархей-палеопротерозойських рифтогенних структур.

The 3.1-3.0 Ga tonalite-trondhjemite-granodiorite rocks of the Middle Dnieper craton were exposed in the provenance of meta-terrigenous rocks of the Hleyuvatka Suite, which forms the upper part of the Krіvоi Rog-Kremenchuk structure. In addition, 3,2; 3,3-3,4 and 3,5-3,7 Ga gneisses were also present in the source area as well as the 2,87-2,85 Ga potassium-sodium granites. Among the Paleoproterozoic detrital zircons, five grains yielded an age of 2,14-2,09 Ga, which indicates the presence of Paleoproterozoic granites in the provenance. The maximum depositional age of the metamorphosed terrigenous rocks of the Hleyuvatka Suite is thus about 2,1 Ga. These data gives ground to distinquish the Hdantsivska and Hleyuvatka suites as a separate Series .

Zircon megacrysts are commonly found in kimberlites and, together with olivine, low-Cr garnet, pyroxene, phlogopite, and ilmenite megacrysts, they constitute a mineral assemblage known as the “low-Cr suite”. The generally close similarity of ages and similar isotope geochemical characteristics of megacrysts and matrix minerals in the host kimberlites support a cognate origin. However, alteration rims commonly develop on zircon and ilmenite megacrysts, providing evidence for a lack of chemical equilibrium between the megacrysts and kimberlitic melts. Here, we report results of a detailed geochronological and geochemical study of zircon megacrysts found in the Middle Devonian Novolaspa kimberlite pipe and dyke located in the Azov Domain of the Ukrainian Shield. The concordia age of zircons is 397.0 ± 2.0 Ma, and it is 14 m.y. older than the age of kimberlite emplacement as defined by a Rb-Sr isochron on phlogopite. The average eHf(397) value for unaltered zircon megacrysts is 6.8 ± 0.14, with the alteration rims having similar Hf isotope systematics. These hafnium isotope data indicate a moderately depleted mantle source for zircon. Unaltered megacrystic zircons have low abundances of trace elements and fractionated REE, with pronounced positive Ce/Ce* anomalies and almost no Eu/Eu* anomalies. In contrast, alteration rims have very high and variable concentrations of trace elements, indicating a reaction between zircon and kimberlite melt. The melt or fluid responsible for zircon and ilmenite megacryst formation, in contrast to kimberlitic melt, was poor in incompatible trace elements, except for the HFSE (Zr, Hf, Nb, Ta, and Ti). The oxygen fugacity during crystallization of the megacryst suite was close to the FMQ buffer. Azov zircon megacrysts do not demonstrate close geochronological and isotope-geochemical similarities with their host kimberlites. They are cognate in the broad sense of being related to the same plume event, but their direct affinity is not clearly defined. The megacryst suite may have crystallized from the earliest melts/fluids that separated from the ascending mantle plume, whereas kimberlite magmas were emplaced 14 m.y. after this event.

The Ukrainian Shield and Voronezh Crystalline Massif constitute the Sarmatian segment of Baltica. Here, only a few mafic-ultramafic dykes and layered intrusions have been dated, recording early Statherian (ca. 1800–1750 Ma) ages. We have determined new U-Pb baddeleyite ages for the Novogol sill (1789 ± 2 Ma) and the Gremyachye intrusion (1781 ± 7 Ma), which fall within the previously established age range of mafic magmatism in Sarmatia. Overall, mafic magmatism started at ca. 1800 Ma and reached a peak at ca. 1790 Ma. Several intrusions were emplaced between ca. 1785 and 1775 Ma. The next significant peak in magmatic activity took place at ca. 1760 Ma, although a few dykes are dated as late as ca. 1750. Together, these rocks constitute the Prutivka-Novogol large igneous province (LIP), with the main components consisting of tholeiitic dolerite, sub-alkaline olivine gabbro, high-Ti (picrite, camptonite) dykes, and kimberlite. Abundant anorthosite-mangerite-charnockite-granite (AMCG) magmatism also occurred throughout the Ukrainian Shield, coeval with tholeiitic magmatism. Early Statherian mafic magmatism was widespread in many parts of the Nuna/Columbia supercontinent, and magmatic barcoding demonstrates that the Sarmatia, Amazonia, Sao Francisco, West Africa, and North China cratons record similar events and were therefore probably in close proximity. This suggests that the Prutivka-Novogol LIP was part of a much larger superplume that affected an extensive area within the newly-formed supercontinent.

The Korosten Plutonic Complex (KPC) of Palaeoproterozoic age is made up of an AMCG suite of rocks. Jotunitic/ferromonzodioritic magmas have been emplaced at the margins or within massive anorthosites and in hypabyssal dykes coeval with the AMCG plutonism. Major and trace element geochemistry shows a calc-alkalic to alkali calcic trend with large variations of composition with SiO2 ranging from 44% to 62% and Mg# from 19 to 36, high concentrations of Fe, Ti and P, up to 20% Fe2O3t, 4% TiO2 and 2% P2O5. The Korosten jotunitic sequence of rocks matches the jotunite liquid line of descent that has been defined in the Rogaland anorthosite province. Both trends are compared to experimental data in dry conditions and medium to high pressure on the evolution of olivine tholeiite melt. It is shown that the initial step of the jotunite evolution characterized by a decrease in SiO2 correlated with increases in Fe and P is not reproduced in the experiments at medium pressure. At high pressure such evolution is possible but cannot yield SiO2 rich melts with further fractionation because of the existence of a thermal barrier. Derivation of jotunite melts from mantle-derived olivine tholeiite would be possible in a polybaric evolution of the melt. However, the polybaric evolution of the anorthosite mush with extraction of the interstitial jotunite melt to form the mafic marginal intrusion is not supported by field evidence of filter press mechanism. Derivation of the jotunite from melting of gabbroic rocks in the crust and their evolution at medium pressure appears as a more convincing mechanism. The ages of formation of the Korosten and Rogaland anorthosites are separated by 800 Myr. It is speculated that the secular cooling of the earth has modified the generation process of the anorthosite. In the KPC a hot zone developed in the crust due to an asthenosphere uprise concomitant with the development of Ni-rich tholeiitic dykes, and in Rogaland, the cooler and more rigid crust was able to subduct and form crustal tongues that were potential source of melts.

The concentrations of 26 trace elements have been determined by laser ablation ICP-MS in zircons from four samples of basic rocks of the Korosten anorthosite-mangerite-charnockite-granite plutonic complex, the Ukrainian Shield. Zircons from the Fedorivka and Torchyn gabbroic intrusions and Volynsky anorthosite massif have distinctive abundances of many trace elements (REE, Sr, Y, Mn, Th). Zircons from the gabbroic massifs are unusually enriched in trace elements, while zircons from pegmatites in anorthosite are relatively depleted in trace elements. High concentrations of trace elements in zircons from gabbroic intrusions can be explained by their crystallization from residual interstitial melts enriched in incompatible elements. The zircons studied demonstrate a wide range of Ti concentrations, which reflects their temperature of crystallization: the zircons most enriched in Ti, from mafic pegmatites of the Horbuliv quarry (20–40 ppm), have the highest temperature of crystallization (845 ± 40 °C). Lower (720–770 °C) temperatures of zircon crystallization in gabbroic rocks are explained by its crystallization from the latest portions of the interstitial melt or by simultaneous crystallization of ilmenite. The Ce anomaly in zircons correlates with the degree of oxidation of the coexisting ilmenite.

The rift system of the Dnieper–Donets trough (DDT) is the largest magmatic area in the East European Platform. Basalts of the Voronezh Crystalline Massif (VCM) are spatially constrained to the eastern shoulder of DDT and occur far away (at a distance of 150–200 km) from the rift axis. The rocks are hosted in the Paleoproterozoic Vorontsovskii terrane and are grouped in a few fields within an area of 200 × 100 km. Basalts at most of the fields were erupted at the boundary between mid- and late Frasnian time in the Late Devonian and can be studied exclusively in core material recovered by boreholes. Newly obtained mineralogical, geochemical, and isotopic-geochemical data show that the Devonian volcanic rocks in VCM are tholeiites (Bas) and basaltic andesites/andesites (ABas). The geological section was examined most exhaustively in the Novokhopersk area (Borehole 175). The bottom of the vertical section is made up of basaltic andesites and andesites (ABas) (thickness 34 m), which rest on an eroded surface of late Frasnian sandstones. The rocks are overlain by a thin (8 m thick) tholeiite sheet (Bas2), which gives way to ABas (13 m) upsection. The top portion of the vertical section is composed of tholeiites with petrography and geochemical evidence of crustal contamination (Bas1) (apparent thickness 5 m). Geochemical parameters of Bas (mg# 42–52 at SiO2 47–51 wt %) are typical of continental tholeiites. The rocks have (87Sr/86Sr)0 = 0.7043–0.7048 and eNd(372) = 2.1–3.5. ABas (mg# 28–31 at SiO2 52–60 wt %) are enriched in Y (48 ppm), and possess Nb/Nb* = 0.7–0.8 and high Zn/Cu = 1.9–2.3. The rocks have (87Sr/86Sr)0 = 0.7034–0.7048 and Nd–eNd(372) = 0.1. Some portions of Bas melts assimilated the upper crustal material, which was similar to Paleoproterozoic granites, and ABas are contaminated in the lower crust with derivatives of Early Cambrian alkaline mafic melts. Petrographic data and simulations of fractional crystallization show that olivine and high-Mg clinopyroxene were the first to crystallize from the melt. After this, clinopyroxene and plagioclase simultaneously crystallized at temperatures from 1070 to 1020°C in Bas and at 1040–900°C at f O2 below QFM + 1 in ABas. The source of ABas was likely a network of hornblendite or amphibole pyroxenite veins in peridotite in the lithospheric mantle or amphibolized peridotite cumulate in an underplating zone; and Bas were derived from spinel peridotites of an asthenospheric diapir. The setting of the basalts relative to the DDT axis and the asymmetric zoning of magmatism in DDT (with kimberlites and other deep rocks constrained to the western shoulder and tholeiites occurring in the axial part of the rift and its eastern shoulder) can be explained by the model of an asymmetric rift structure with a translithospheric detachment gently dipping beneath VCM.

A maximum depositional age (MDA) of 551.2 ± 4.2 Ma for the black argillites of the Kalyus Beds, Nagoryany Formation (East European Platform, northeastern Republic of Moldova) is reported based on the youngest cluster of detrital zircons dated by LA-ICP-MS. Their source can be linked to an arc-related volcanism that fed the tuffite layers interbedded in the basal part of the Kalyus Beds and reasonably support our inference that the reported MDA is consistently compatible with the true depositional age (TDA) of the Kalyus Beds. The volcanic event that led to ash deposition for the tuffites may be related to the active margin processes which developed adjacent to the Baltica palaeocontinent. Hf isotope values of two detrital zircons from the youngest cluster suggest mantle input, and a third detrital zircon was derived from felsic rocks that originated from re-melting of the older crustal rocks. The older detrital zircon clusters correlate well with known published ages of the different lithotectonic units from the East European Platform. The precise geochronological U–Pb ages, including the Kalyus detrital zircon age, offer outstanding data to calibrate the sedimentary and volcanic events, and the evolution of the Ediacaran biota in the Moldova-Podillya Basin, specifically the Miaohe biota biozone, for which a few newly identified taxa significantly increase its taxonomic diversity. The anoxic conditions together with the associated phosphorites that controlled the deposition of the Kalyus argillites represent a major depositional event in this area of the Baltica palaeocontinent, and can be correlated with other worldwide anoxic events during the late Ediacaran.

We present the results of a study of an Eoarchean rock assemblage in the Dniester-Bouh Domain of the Ukrainian Shield. This comprises granulite-facies granitoids intercalated with mafic and ultramafic granulites. Zircon U-Pb geochronology indicates enderbite crystallisation at 3786 ± 32 Ma, followed by a subsequent event at ca. 3500 Ma. Several events can be tentatively identified that affected these rocks between ca. 3000 and 2700 Ma. The last zircon growth event took place in response to granulite facies metamorphism and included two separate episodes at ca. 2000 and ca. 1900 Ma. The oldest two zircon populations in enderbites have eHf values around 0, indicating their crystallisation from a protolith with a short crustal residence time. Zircons that crystallised during the 3000–2700 Ma event(s) vary in Hf isotope systematics from eHf ~ 1 at ca. 3000 Ma to eHf ~ −14 at c. 2700 Ma. Paleoproterozoic zircons reveal even more significant variations in eHf value from +6 to –22. Such variations are indicative of juvenile input and mixing with old non-radiogenic Hf. All Eoarchean rocks are depleted in incompatible trace elements and have negative Ta-Nb, P, and Ti anomalies. Compared to the typical TTG associations, enderbites record depletion in felsic components (SiO2, Na2O, K2O, Rb, Th), and enrichment in mafic ones (TiO2, MgO, CaO, V), allowing them to be defined as “mafic” or “depleted” TTG. Geochemical data indicate that mafic and ultramafic rocks of the Dniester-Bouh Domain formed by shallow high-degree melting of the mantle, with the absence of garnet in their source, and the presence of residual Ti-bearing minerals and/or amphibole. In contrast, enderbites were formed from a mixed garnet-bearing amphibolite – eclogite source, i.e. melting over a range of pressures/depths. Our preferred model for the formation of the Eoarchean rock association involves the shallow melting of mantle and formation of basalts and accompanying ultramafic cumulates at a spreading centre, with subsequent underthrusting of one segment of oceanic crust beneath the other, and partial melting of hydrated metamorphosed (eclogitized) mafic rocks in the underthrust plate, leading to the formation of the TTG melts.

Zircon occurs as a minor constituent in most differentiated magmatic rocks. Its robustness to later modification means that its isotopic and chemical composition generally records conditions prevailing when it formed, and the systematic changes in the oxygen isotope record of zircon through geological time have been used to trace the temporal evolution of crust–mantle interaction and intra-crustal recycling. Here we present U–Pb, Hf, and oxygen isotopic compositions for high grade metamorphic Archean rocks from the Dniester-Bug Series, western Ukrainian Shield. Zircon from a quartz-dominated rock is up to 3.8 Ga old, and enriched in 18 O compared to most previously reported values from Archean zircon. Similar values are recorded in zircon cores, which exhibit a variety of internal textures including magmatic-style oscillatory zonation, and rims. If this rock is metasedimentary and the isotope signatures in cores are primary, the zircon sources were characterized by heavier oxygen isotopic compositions than any known major area of Archean crust. Alternatively the O isotope compositions have been modified. We show that a large fraction of the analyzed zircon appear not to be modified by radiation damage, and speculate that O exchange may have taken place by diffusion during extreme metasomatic alteration of the host rock. The possibility that igneous-looking, apparently unaltered zircon may not preserve a primary oxygen isotope signature has implications for its use in the interpretation of crustal evolution, including early terrestrial geodynamics.

Age and sulfur isotope composition of the Prutivka intrusion (the 1.78 Ga Prutivka-Novogol large igneous province in Sarmatia)

International audience; Palaeoproterozoic (ca. 1.8 Ga) mafic and ultramafic dykes are widely distributed within the whole Sarmatian segment of the East-European craton. This paper focuses on new geochronological, geochemical and isotope data obtained for mafic and ultramafic dykes of the Ingul terrain. Geochronological data available for these dykes indicate ages around 1800 Ma. We provide a new U–Pb zircon age of 1810 ± 15 Ma obtained for a dolerite dyke in the Kirovograd area. Geochemical and petrographical data allow identification of three groups of dykes: (1) kimberlites, (2) high-Mg# subalkaline rocks (picrite, camptonite, subalkaline dolerite etc.) and (3) tholeiite dolerite. Rocks of these groups were probably derived from different sources. εNd1800 values of studied rocks vary from 0.7 to 2.8. The highest values were obtained for mantle xenoliths and their kimberlite host (εNd1800 = 2.5–2.8). Rb–Sr data yield a regression age of 1729 ± 20 Ma with an initial 87Sr/86Sr = 0.70366 ± 41 (MSWD = 10.8). The whole-rock lead isotope data scatter, but data for sub-groups of samples can tentatively be fitted to parallel 1.8 Ga isochrons. The geochemical data indicate rocks to have formed by partial melting and the degree of melting is thought to be a function of formation depth, the latter ranging from sub-lithospheric to lower-crustal levels; we assume that melting was caused by a mantle plume. Dyking in the Ingul terrain was closely associated in time and space with metasomatic albitites that host numerous economic U deposits.

The Kalyus Beds of the late Ediacaran Nagoryany Formation occurring in the northeastern part of the Republic of Moldova are dominated by black argillites with phosphorites and calcareous concretions. Four lithological groups were examined with respect to their rare earth element (REE), major and trace element geochemistry: phosphorites, enriched argillites, pure argillites and carbonates. Phosphorites and enriched argillites exhibit a pronounced middle-REE bulge suggesting a strong diagenetic uptake of REEs. Y/Ho ratios are mostly 90% of REEs from lithogenous sources. Pure argillites show a flat REE distribution similar to that of average upper continental crust (UCC), indicating that REEs are likely related to detrital siliciclastics derived from felsic to mafic source rocks of the adjacent regions of Baltica, which was isolated within paleo-oceans during the late Ediacaran. Carbonates show a light-REE depleted pattern with relatively high Y/Ho ratios (up to 53) that suggests the preservation of a predominantly hydrogenous (seawater-derived) REE signal. Ce/Ce* ratios of ∼0.80–1.02 reflect suboxic to anoxic seawater conditions. This is a locally and temporally constrained anoxic event, since widespread oxic conditions were specific for the continental margins of Baltica. The phosphorites and enriched argillites groups of the Kalyus Beds show high middle-REE enrichment comparable to those of other known world phosphorite deposits. Their total REE contents are high (793–1735 ppm) and are of potential economic interest. These results provide insights for expanding global REE exploration targets and may have implications for a better understanding of the depositional environments during the late Ediacaran.

Middle-to-late Ediacaran (575–541 Ma) marine sedimentary rocks record the first appearance of macroscopic, multicellular body fossils, yet little is known about the environments and food sources that sustained this enigmatic fauna. Here, we perform a lipid biomarker and stable isotope (δ15Ntotal and δ13CTOC) investigation of exceptionally immature late Ediacaran strata (, The environments and food sources that sustained Ediacara biota 575-541 million years ago remain unclear. Here, the authors perform lipid biomarker and isotopic analyses on biota fossil-containing Ediacaran strata from Baltica and propose the presence of a microbial loop bolstered by bacteria.

The results of simultaneous LA-ICP-MS measurements of 207Pb/206Pb and Hf isotope ratios are reported for zircons separated from five Ukrainian shield sedimentary rocks: (1) c. 3.0 Ga quartzite of the Bug Series; (2) c. 2.0 Ga quartzite of the Topilnya Series; (3) c. 1.75 Ga quartzite of the Ovruch Series; (4) c. 1.2–1.0 Ga sandstone of the Polissya Series; and (5) c. 0.6 Ga conglomerate of the Volyn Series. The age–Hf isotope (ɛHfT) data indicate four main crustal growth events at 3.75, 3.20–3.15, 2.2–2.0, and 1.5 Ga in the south-western part of the East European craton (EEC). An additional rather minor event could have place at 2.5–2.4 Ga. The oldest event is represented by enderbites of the Bug domain in the south-western part of the Ukrainian shield. The second crust-forming event occurred at c. 3.20–3.15 Ga and it is documented by detrital zircons separated from the Bug Series quartzite and metasediments of the Soroki greenstone belt, Azov domain. A small number of zircons with positive ɛHfT values reveal some input of the juvenile material into the crust at 2.5–2.4 Ga, whereas the 2.2–2.0 Ga event is dominated by zircons with positive ɛHfT values. The youngest event is represented by numerous zircons that crystallized at c. 1.5 Ga. The possible sources of these zircons are the rock complexes of the south-western part of the Fennoscandian shield.

This research gained financial support granted by the Royal Society, UK (2006/R4 IJP), and the Swedish Institute, Sweden. This paper is NORDSIM contribution number 484, and publication no. 62 of the Large Igneous Provinces – Supercontinent Reconstruction – Resource Exploration Project (CAMIRO Project 08E03, and NSERC CRDPJ 419503-11) (www.supercontinent.org, www.camiro.org/exploration/ongoing-projects), and a contribution to IGCP 648. The Ukrainian shield hosts two Palaeoproterozoic anorthosite-mangerite-charnockite-granite (AMCG) complexes (the Korosten and Korsun-Novomyrhorod complexes) that intruded Palaeoproterozoic continental crust in north-western and central parts of the shield, respectively. We report results of U-Pb zircon and baddeleyite dating of 16 samples from the Korosten plutonic complex (KPC), and 6 samples from the Korsun-Novomyrhorod plutonic complex (KNPC). Fifteen zircon samples from both complexes were also analysed for Hf isotopes. These new, together with previously published data indicate that the formation of the KPC started at c. 1815 Ma and continued until 1743 Ma with two main phases of magma emplacement at 1800-1780 and 1770-1758 Ma. Each of the main phases of magmatic activity included both basic and silicic members. The emplacement history of the KNPC is different from that of the KPC. The vast majority of the KNPC basic and silicic rocks were emplaced between c. 1757 and 1750 Ma; the youngest stages of the complex are represented by monzonites and syenites that were formed between 1748 and 1744 Ma. Both Ukrainian AMCG complexes are closely associated in space and time with mantle-derived mafic and ultramafic dykes. The Hf isotope ratios in the zircons indicate a predominantly crustal source for the initial melts with some input of juvenile Hf from mantle-derived tholeiite melts. The preferred model for the formation of the Ukrainian AMCG complexes involves the emplacement of large volumes of hot mantle-derived tholeiitic magma into the lower crust. This resulted in partial melting of mafic lower-crustal material, mixing of lower crustal and tholeiitic melts, and formation of ferromonzodioritic magmas. Further fractional crystallization of the ferromonzodioritic melts produced the spectrum of basic rocks in the AMCG complexes. Emplacement of the ferromonzodioritic and tholeiitic melts into the middle crust and their partial crystallization caused abundant melting of the ambient crust and formation of the large volumes of granitic rocks present in the complexes. Postprint

This paper addresses the geochemistry of intrusive (Osinitsk complex) and volcanic (Klesov Group) rocks of the Osnitsk-Mikashevichy volcanoplutonic belt (OMVPB) of the Ukrainian shield, which is an active continental margin existing approximately 1980–2000 Ma ago. The Osnitsk complex comprises a wide range of rocks, from ultrabasics to granitoids, and the Klesov Group is dominated by extrusive rocks of basaltic and rhyolitic compositions metamorphosed under epidote-amphibolite facies conditions. The Sr-Nd-Hf isotopic systematics (ɛSr1990 from −4 to +10, ɛNd1990 from −0.6 to +2.3, and ɛHf1990 from 0.1 to 1.4) indicates a juvenile source for the OMVPB rocks. Geochemical data suggest independent origin of the rocks of gabbroid (SiO2 60 wt %) series. The gabbroids are subdivided into pre- and post-granite groups on the basis of the higher contents of incompatible trace elements and lower contents of compatible elements in the post-granite rocks. The geochemical characteristics of the two groups of basic rocks indicate their formation in a convergent tectonic setting. The origin of the granitoid melts is attributed to the low-degree (eutectoid) melting of basic rocks at relatively low temperatures.

The oldest crust in the Ukrainian Shield occurs in the Podolian and Azov domains, which both include Eoarchaean components. U- Pb age data for Dniestr-Bug enderbites, Podolian Domain, indicate that these are c. 3.75 Ga old, and Lu-Hf isotope data indicate extraction from chondritic to mildly isotopically depleted sources with 1Hf up to c. +2. Nd model ages support their Eoarchaean age, while model ages for Dniestr-Bug metasedimentary gneisses indicate that these also include younger crustal material. Most of the Hf-age data for metasedimentary zircon from the Soroki greenstone belt, Azov Domain, reflects Eoarchaean primary crustal sources with chondritic to mildly depleted Hf isotope signatures at 3.75 Ga. A minor portion is derived from Mesoarchaean crust with a depleted 1Hf signature of c. +4 at 3.1 Ga. U- Pb zircon ages from Fedorivka greenstone belt metasediments are consistent with the Soroki age data, but also include a 2.7- 2.9 Ga component. Nd whole rock model ages provide support for a younger crustal component in the latter. Both domains have been subject to Neoarchaean, c. 2.8 Ga, and Palaeoproterozoic, c. 2.0 Ga, metamorphism. The spatial distribution indicates that the Podolian and Azov domains evolved independently of each other before the amalgamation of the Ukrainian Shield. Gold Open Access: This article is published under the terms of the CC-BY 3.0 license.

International audience; The sedimentary cover of the East European Craton (EEC) is unique because of its low degree of diagenetic alteration that allows preservation of the original “source to sink” relationships. The present study provides U-Pb and Hf zircon data for the entire Proterozoic sedimentary section of the EEC based on samples from five boreholes in Belarus within the Volyn-Orsha Basin, one of the most important sedimentary basins of the craton. Twenty-one samples of mudstones and sandstones were selected for detrital zircon U-Pb geochronology, supplemented by the Hf isotope analyses of zircons from 6 samples representing different U-Pb age spectra and bulk rock XRD mineralogy of all mudstone samples collected from the studied boreholes. Five clastic successions in the Volyn-Orsha Basin are characterized by different sources of detrital material: (1) The Mesoproterozoic Pinsk Suite with a narrow population of c. 2.0 Ga zircons, (2) The Orsha Suite with a broad 1.3–3.2 Ga zircon age distribution, (3) Glacial sediments of the Vilchitsy Series with an age spectra similar to the Orsha Suite, except for a c. 1.0 and 1.2 Ga cluster, (4) The Volyn and Valdai Series, including lowermost Cambrian, with a narrow trimodal population of 0.5, 1.5, and 1.8 Ga zircons, and (5) lower Cambrian (?) sediments with a diffused zircon age spectrum, including a 500–700 Ma cluster. Maximum depositional ages were constrained for the Vilchitsy Series at 977 ± 6 Ma and for the Volyn Series at 579–545 ± 4 Ma. Combined Hf zircon data indicate four episodes of new continental crust generation at 3.3, 2.8, 2.1–2.3 and 1.8 Ga, suggestive of source terrains within the crust of the present-day EEC. These sources experienced subsequent reworking of crust at c. 1.8 Ga and 550–600 Ma. Only a lower Cambrian sample lacks any trend or clustering within the Hf data probably due to mixing of zircons from exotic and local sources. Paleogeographic models explaining these provenance signals in terms of intracratonic erosion and sediment transport are presented.

The Ukrainian Shield comprises the exposed crust of the large Palaeoproterozoic protocraton Volgo-Sarmatia, which together with the Fennoscandian crustal segment constitutes the East European Craton ("Baltica"). Geological and geophysical data indicate that 1.80 to 1.75 Ga mafic dykes related to anorthosite-mangerite-charnockite-granite (AMCG) plutons are widespread within the Ukrainian Shield. We examined their ages, distribution patterns, orientations and compositions in three different crustal blocks (Volyn, Ingul and Azov), and found close spatial relationships with major strike-slip fault systems developed during two phases of extension. The early, 1.80-1.77 Ga, generation of mafic dykes mostly follows NW (330 +/- 20 degrees) and more rarely N-S- or E-W-trending faults corresponding to major NE-SW extension (the Submoshorino phase). These dykes contain olivine dolerites, picrites, camptonites, lamprophyres, kimberlites and other rocks belonging to tholeiitic and subalkaline jotunitic series. The compositions of these dykes differ between the host blocks, but all feature upper mantle geochemical signatures such as high contents of Ni and Cr, and positive values of epsilon Nd-(1800) up to + 2.8. High degrees of REE fractionation indicate deep levels of mantle melting, which is particularly characteristic of the Ingul block as marked by the most extensive and dense mafic dyke swarms. The later, 1.76-1.75 Ga, dyke swarms occur close to the most voluminous AMCG suites of similar age and were emplaced during the second (Korsun) phase of faulting when all the older strike-slip fault zones were reactivated and partly transformed to tensional faults by E-W extension. These dyke swarms mainly trend 030 +/- 20 degrees. They are jotunitic and their isotopic signatures indicate a greater participation of crustal sources in the parent melts. The overall transtensional tectonic setting of the mafic dyking associated with the AMCG magmatism in Volgo-Sarmatia was created by convergent tectonics and postcollisional collapse of the thickened lithosphere, as well as by mantle delamination coupled with the rotation of Volgo-Sarmatia between 1.80 and 1.75 Ga. This agrees with palaeomagnetic reconstruction suggesting rotation(s) of Volgo-Sarmatia during its protracted oblique docking with Fennoscandian terranes and Laurentia as supercontinent Columbia (Nuna) was assembled. (C) 2012 Elsevier B.V. All rights reserved. (Less)