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The early stages of basic–ultrabasic magmatism in Sarmatia are characterized by the appearance of ultrabasic rocks formed from the mantle with an abnormally high iron content. Therefore, it is important to study them as the source of information about the stages and causes of the activity of the mantle and its possible composition. This magmatism has been recorded in Sarmatia since the beginning of the Eoarchean. The relics of Eo- and Paleoarchean basic and ultrabasic rocks were found in the Dniester–Bug, Kursk, and Azov provinces, which underwent tectonic reconstruction in the Mesoarchean and Paleoproterozoic. Mesoarchean basic–ultrabasic magmatism is manifested in all provinces of Sarmatia and is represented by effusive and intrusive facies. The Mesoarchean greenstone belts composed of komatiites and basalts have been well preserved in the Middle Dnieper province; in other provinces, they are strongly deformed and form narrow linear structures. The Paleoproterozoic endogenous activity in Sarmatia differs from that in other regions in the almost complete absence of magmatism in the period 2.5–2.3 Ga and its significant manifestation 2.1–2.0 Ga. The magmatism in Sarmatia at this stage is similar in the ratios of basic–ultrabasic and granitoid complexes to the magmatism in South Africa but differs from that in Fennoscandia and Canada. The volume of granitoids coeval with basic rocks is larger than the volume of mantle magmatism. The igneous complexes formed 2.1–2.0 Ga in Sarmatia and South Africa are also similar in the presence of norites, the enrichment in Ni and platinum group elements, and the ratio of granitoids and basic–ultrabasic rocks. Magmatic activity (first of all, basic–ultrabasic magmatism in ancient cratons) is not a synchronous phenomenon on a planetary scale and varies greatly in the volume of produced material within the same time intervals. Early Precambrian basic–ultrabasic rocks (volcanics of greenstone belts, intrusions of large igneous provinces, and layered massifs) resulted from plumes, whose derivates formed within the lower and upper mantle and/or the upper mantle and crust, which determined the heterogeneous composition of igneous rocks. The spatial heterogeneity and nonsynchronic occurrence of basic–ultrabasic magmatism might have been due to impact events serving as the triggers of plumes.

We study the P–T conditions and age of metamorphic evolution of the rocks that make up the Korvatundra structure in the northeast of the Fennoscandian Shield. The rocks underwent progressive metamorphism of the amphibolite facies at 625–660 ºC and 8.7–8.8 kbar 1945 ± 34 Ma (Sm–Nd data). The pegmatite cutting the metamorphic paragenesis that formed at this stage has an age of 1917 ± 6 Ma (zircon U–Pb data). Metamorphic transformations after 1917 Ma are manifested locally as discrete zones of blastomylonites in the rocks of the northern part and some inner sites of the Korvatundra structure. Both local increases and decreases in temperature and pressure are possible in these zones. The formation of light titanite with an age of 1863 ± 44 Ma marks the next stage of shear strain. Low-temperature alterations (chloritization and silicification) took place in the zones of final deformations 1722 ± 5 Ma (Rb–Sr data). Beginning from 1.94 Ga, the general deformational and metamorphic history of the Korvatundra structure, Lapland Granulite Belt, and Tana Belt confirms the assumption of the formation of a single inverted metamorphic zoning within the Korvatundra structure and the overlying Lapland–Kolvitsa Collision Belt in the Paleoproterozoic. The obtained data supplement the idea of the Paleoproterozoic geodynamic evolution of the Lapland–Kola orogen.

The Sr-isotope composition of the Central Azov Group carbonates (0.70322-0.70352) and Nd model age of silicate sediments (2.34-2.31 Ga) has been reported. The U-Pb age of trondhjemite (2052+5 Ma) cutting the carbonates has been determined. According to the obtained data, the marine sedimentary cover of the Azov block making up the Early Precambrian Sarmatia Continent emplaced in the Early Paleoproterozoic at 2.23-2.34 Ga.

The Central Indian Tectonic Zone (CITZ) is major E-W trending suture zone between Northern and Southern Indian crustal blocks. The southern portion of the CITZ comprises three lithotectonic units: Tirodi Gneissic Complex (TGC), Sausar Mobile Belt (SMB) and Bhandara-Balaghat Granulite Belt (BBGB). Elemental and isotopic data are used to constrain the genesis of granitoids and their protoliths, which may help us to understand the Proterozoic crustal evolution in CITZ. Geochemical and isotopic results are consistent with previous studies that these granitoid plutons are linked to the felsic magmatism of the Columbian crustal assembly in India, North America and North China. Granitoids varies from tonalite to granite, alkalic to calcic, metaluminous to peraluminous composition. Normalized elemental ratios of La/Sm, La/Yb, La/Lu, and Gd/Yb depict variable LREE enrichments and varying degrees of partial melting of heterogeneous crustal/lithospheric sources. The studied rocks are characterized by positive anomalies for Pb and negative anomalies for Nb, Sr, P, Ti, which indicate the influence of subduction-zone fluids in the source regions. Negative anomalies for K, Sr, and Ti for SMB and BBGB granitoids may also be attributed to K-feldspar, plagioclase, and Fe-Ti oxide fractionation. However, TGC porphyritic leucogranites display K, Ba and Eu positive anomalies, probably related to the accumulation of K-feldspar phenocrysts. Nd-Sr data presents initial ratios of 143 Nd/ 144 Nd t=1.6 Ga ranges between 0.509961 and 0.510300; εNd t=1.6 Ga ranges from -5.3 to -11.9 with TDM ages ranging from 2.20 to 2.78Ga for TGC granitoid. The ratios of 143 Nd/ 144 Nd t=1.6 Ga ranges between 0.510232 and 0.510985; εNd t=1.6 Ga ranges from +0.2 to +8.2 and TDM ages varies from 1.5 to 3.0 Ga. The initial 87 Sr/ 86 Sr t=1.6 Ga ratios ranges between 0.699834 and 0.797151 for SMB granitoid. However, BBGB granitoids show the ratios of 143 Nd/ 144 Nd t=1.6 Ga ranges between 0.509752-and 0.510910; εNd t=1.6 Ga ranges from +6.7 to -16, and TDM ages range from 1.51 to 3.29 Ga. The initial 87 Sr/ 86 Sr (t=1.6 Ga) ratios varies between 0.705096 and 0.717440. These ranges of εNd (t) and TDM values possibly indicate their derivation from enriched and heterogeneous crustal/lithospheric sources, and minor components from depleted lithospheric sources.