In numerous orogenic belts, A-and I-type granitoids may coexist within a single pluton or intrusive series. These granitoids may be semi-contemporaneous and exhibit converging chemical signatures, implying similar petrogenetic histories. However, compositionally similar plutons may mark different tectonic settings. A notable example is observed in the Late Paleozoic granitoids of the Trans-Altai Gobi (SW Mongolia). Two temporally discrete stages of A-and I-type granitoids were identified here through zircon U-Pb and amphibole 40Ar-39Ar dating: Late Carboniferous (ca. 317 Ma) and Early Permian (295-283 Ma). The Late Carboniferous granitoids are hypersolvus A-type, containing aegirine with alkali amphibole, and are associated with a bimodal volcanic sequence. The Early Permian granitoids include subsolvus I-type and hyper-and transsolvus A-type, containing Ca-Na amphibole and/or biotite, but lacking aegirine. Gabbroid enclaves and mafic dikes were observed within one of these plutons. The mafic rocks exhibit chemical signatures similar to those of intraplate basalts, suggesting a potential origin from the asthenospheric mantle with addition of the subduction-modified lithospheric material. The Late Carboniferous and Early Permian A-and I-type granitoids exhibit a similar Nd isotopic signature (epsilon Nd(t) from +5.5 to +6.8), which correspond to the ranges of the Hercynian crustal isotope province and the values observed in the associated mafic rocks. However, the distinct chemical characteristics of mafic and salic rocks preclude common origin. We propose a similar petrogenetic scenario for the Late Carboniferous and Early Permian granitoids inferred in partial melting of earlier calc-alkaline subduction-related granitoids. Due to low melting degree, the Late Carboniferous A-type rocks are relatively enriched in incompatible Nb, Ta, REE, Zr, and Hf, but are strongly depleted in Ba, Sr, and Eu, which were preferentially partitioned into residual plagioclase and K-feldspar. An increased degree of melting in the Early Permian promoted the formation of both A-and Itype granitoids were not enriched in incompatible elements and moderately depleted in Ba, Sr, and Eu. The studied granitoids record two different tectonic stages of crustal extension in the Trans-Altai Gobi, adjacent Eastern Junggar, and western Central Asian Orogenic Belt (CAOB) as a whole. The Late Carboniferous A-type granitoids and bimodal volcanics were emplaced immediately after the termination of Early Carboniferous subduction-related magmatism and mark a short-term post-accretionary stage following the closure of the South Gobi-Kelameili branch of Paleo-Asian Ocean. The Early Permian A-and I-type granitoids belong to an episode of widespread anorogenic magmatic activity covering various terranes in the western CAOB. This magmatism could be initiated by thermal expansion from the Tarim mantle plume into the CAOB area and/or by delamination/dripping of the lower continental crust, which was thickened due to prior multiple accretions of terranes sandwiched between the Tarim and Siberian cratons.

The investigated amphibolites from the Slasten lithotectonic unit are found as a strongly elongated body trending north-south at the eastern slope of the Pirin Mountain, near the village of Ilinden. These rocks are hosted by biotite and biotite-amphibole gneisses, some partially migmatized and containing thin intercalations of marble. The mineral composition is amphibole, plagioclase, epidote, quartz, garnet, pyroxene, titanite, and calcite. P-T conditions of metamorphism are in the range 691-724 degrees C and 0.74-0.86 GPa. LA-ICP-MS analyses of zircons yield a Middle Triassic (246.4 +/- 3.2 Ma) age of formation of these amphibolites.

The eclogites from Sredna Gora Mts. occur as small isolated bodies enclosed in amphibolites, two-mica schists and migmatized gneisses. They have tholeiitic composition and characteristics of MOR basalts. Three equilibrium mineral associations are distinguished in eclogites: (1) high-pressure (HP) – Grt+CPx(Omp)+Zo+Rt; (2) middle-pressure-high temperature (MP/HT) – Opx+CPx+Pl and middle pressure – middle temperature (MP/MT) presented by Amp+Pl+Qzt+Ep+Ilm+Ttn. The P-T conditions of HP stage reached values of 1.6–2.02 GPa and 650–690 °С. After the HP stage and CPx-Pl symplectite formation, the eclogites underwent a short-lived granulite facies overprint under temperatures similar to those of the HP event. The P-T conditions of the retrograde amphibolite facies overprint are in the range 620–650 °C and 0.6–0.8 GPa. The obtained age of 319±28 Ma by Sm-Nd garnet+whole rock method is interpreted as age of the final retrograde metamorphism under P-T conditions of high temperature amphibolite facies.

The Rhodope massif and the Kraishte Zone are parts of the Internal Balkanides separated by Gabrovdol detachment. In the most southwestern part of Bulgaria one of the units of the Serbo-Macedonian Massif (the western part of the Rhodope Massif) the Vertiskos Unit crops out. Part of this unit represented by metagabbro-metadiorites is exposed in an area of about 60 km2 in the central part of the Vlahina Mountain. These rocks are metamorphosed at lower amphibolite facies conditions (T = 630–670 °C and P = 0.85–1.05 GPa). LA-ICP-MS U-Pb dating of zircons display concordant age of these rocks of 541±2.6 Ma. The petrological and isotopic investigations show significant differences with the rocks of the Vertiskos Unit and allow us to assign these rocks to the basement of the Kraishte zone (Struma Unit).

In tectonic history of many orogenic belts, alkaline granitoids with A-type affinity mainly reveal lithosphere extension events. However, precise dating of these rocks is often hampered by several problems either due to absence of accessory zircon or due to high U and Th contents disturbing the U-Pb isotope system. This study reports results of chemical abrasion isotope dilution-thermal ionization mass spectrometry (CA ID TIMS) U-Pb dating of zircon from five plutons of aegirine- and/or alkaline amphibolebearing alkali-feldspar granites and quartz syenites from the Trans-Altai Gobi (SW Mongolia) and Northern Mongolia in the Central Asian Orogenic Belt and reveals their close petrogenesis in different tectonic position. In the SW Mongolia the earliest Carboniferous alkaline granitoids (ca. 358-346 Ma) were formed during the post-accretion extensional event suggesting the Late Devonian accretion of the TransAlai Gobi-Eastern Junggar oceanic island arc to the Mongolian-Chinese Altai peri-Siberian continental margin. Alkaline granitoids of the Northern Mongolia were emplaced in the Early Permian during two independent geographically overlapping anorogenic near-coeval igneous pulses. The earliest pulse (ca. 285 Ma) related to evolution of the western half of the Northern Mongolia-Western Transbaikalia volcano-plutonic belt of alkaline granitoids with the bimodal volcanic sequences, is ascribed to the most significant Early Permian magmatic event throughout the Central Asian Orogenic Belt. The latest pluton (276 +/- 1 Ma) identifies the initial emplacement stage of the Middle Permian-Early Triassic Khangai granitoid batholith. Alkaline granitoids from the Trans-Altai Gobi and Northern Mongolia possess similar ferroan, mainly peralkaline, A(2)-type granite geochemical characteristics, but differ in Nd isotopic signatures. For the Trans-Altai Gobi plutons epsilon(Nd)(t) = +6.7; for Northern Mongolian plutons epsilon(Nd)(t) varies between -1.7 to + 0.6. These values are consistent with the Nd isotopic evolution of the continental crust of the hosting terranes, 'Hercynian' isotope province for the Trans-Altai Gobi and `Caledonian' province with a pre-Ediacaran microcontinent crust for the Northern Mongolia. Thereby studied alkaline granitoids were formed manly though anatexis of the host terrane crust during post-accretion and anorogenic extension events in different parts of the Central Asian Orogenic Belt. (C) 2023 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

Metaeclogites from the Devesil Unit, East Rhodopes are studied. Well preserved eclogite paragenesis is presented by omphacite+garnet+rutile and is obliterated by still high temperature retrograde assemblage of newly formed garnet, diopside, amphibole, plagioclase, titanite, and quartz. The P-T conditions of the high pressure metamorphism are in the range 620–665 °C and 1.8–2.0 GPa, whereas the retrograde stage occurs at temperature 600–650 °C and pressure 0.6–0,8 GPa. Cathodoluminescence images and LA-ICP-MS dating of zircon grains point to multiple metamorphic origin of the mineral the earliest with Late Permian–Early Triassic age, followed by Early Jurassic and Early Cretaceous metamorphic events.

In this study, new geological, geochronological, geochemical, and Nd-Hf isotopic data are presented for the Melange Zone within the Zavkhan terrane, Mongolia, and the terrane structure, early Neoproterozoic continental crust growth, and microcontinent formation in the north-central part of the Central Asian Orogenic Belt (CAOB) are discussed. The Melange Zone separates high-grade complexes of the northwestern part of the Zavkhan terrane and unmetamorphosed Neoproterozoic Zavkhan Formation covered by Ciyogenian-Cambrian shelf deposits of the southwestern part. Zone consist of a lower-grade association of basalts, basaltic andesites, rarely felsic volcanic rocks, trondhjemites of the Kharuul Massif and variably metamorphosed from greenschist- to upper amphibolite-facies, and high-grade metamorphic rocks including quartzite-gneisses, hornblende schists, and amphibolites with relics of eclogite and blueschist-facies metamorphism assemblages. Emplacement of trondhjemites and gabbro dykes of the Kharuul Massif occurred at about 960-930 Ma. Geochemical, Nd whole-rock, and Hf-in-zircon isotopic data indicate an oceanic island arc setting for the lower-grade association. LA-ICP-MS dating and Hf-in-zircon data for detrital zircons from the quartzite-gneisses of the Melange Zone indicate that the sources comprise Palaeoproterozoic (ca. 2.02 and 2.48 Ga), Neoarchean (ca. 2.59 and 2.67 Ga), and Mesoarchean (ca. 2.8 and 3.0 Ga) magmatic and metamorphic crustal rocks as well as 2.6-2.5 Ga juvenile complexes. High-grade amphibolites show geochemical similarity to continental arc and within-plate basalts, and were formed from enriched mantle sources. Obtained combined with published data demonstrate that the Zavkhan terrane represents composite terrane composed of ca. 960-930 Ma island arc complex, and ca. 860-800 Ma active continental margin complexes in the north and reworked at ca. 800-720 Ma early Precambrian continental crust in the south, which are separated by a Melange Zone. We speculate that formation of the latest Mesoproterozoic-early Neoproterozoic island arc and active continental margin complexes in the north-central CAOB could be related to the assembly of the Rodinia supercontinent at ca. 1.1-1.0 Ga, which initiated subduction in Mirovian Ocean and led to the development of accretionary orogens around supercontinent margins. (C) 2020 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

The article presents new age data on the ‘key’ Early Paleozoic igneous complexes located in the central part of the Bureya continental massif of the Central Asian Fold Belt. Porphyroblastic quartz monzonites of the Kivili complex are dated to 453±2 Ma. The age of gneissic granites of the Sularin complex is ~481 Ma. The Sm-Nd isotope stu­dies show that Late Ordovician quartz monzonites were formed mainly from crustal sources with Paleoproterozoic Nd model isotopic ages. Both ancient (Paleoproterozoic?) and younger sources were involved in the formation of Cambrian granites. Our data, as well as previously published materials, suggest several stages of the Early Paleozoic magmatism in the evolution of the Bureya continental massif: ~541, ~504–500, ~487, ~474 and ~453 Ma. Early Paleozoic magmatism developed under a similar scenario in the Jiamusi continental massif. In addition to the synchronism of Neoproterozoic magmatism within these continental massifs, this feature testifies to their common geological history.

Geological and geochronological U-Pb (zircon ID-TIMS) and Ar-40/Ar-39 (amphibole) data were obtained for six anorogenic magmatic associations in the Gobi Altai, southwestern Mongolia, in order to reveal its relationships with Late Paleozoic tectonothermal events in the southern part of the Central Asian Orogenic Belt (CAOB). In the Gobi Altai massifs of alkaline granites and grabens filled with bimodal volcanic suites occur as a chain 450 km long east-southeast direction. The massifs and volcanic fields are controlled by contacts of pre-Ediacaran continental crustal blocks with Late Neoproterozoic-Cambrian juvenile ophiolite and arc-type complexes of the Lake zone. Gobi Altai alkaline granites bear sodic-rich mafic silicate minerals and possess typical properties of ferroan A-type granites. Our geochronological data constrain emplacement time of the Gobi Altai alkaline granites and bimodal volcanic rocks at 293 +/- 1-279 +/- 1 Ma. This age interval coincides with timing of the emplacement of I-type granites (with a few S-type granites) and gabbroic intrusions in the Mongolian and Chinese Altai as well as with numerous massifs of A-type granites, layered mafic-ultramafic intrusions, and eruption of bimodal volcanic rocks between the southern edge of the Siberia craton and the northern margins of the Tarim and North China cratons. Hence, the Gobi Altai anorogenic magmatic complexes were produced by a large-scale Late Paleozoic magmatic event (or events) that encompassed a wide spectrum of terranes in CAOB. The most realistic models explaining these magmatic processes are: (i) the effect of the Tarim mantle plume, (ii) slab (or slabs) break-off after subduction blocking due to accretion of terranes of various types. (c) 2015 Elsevier Ltd. All rights reserved.

Systematic and regular epidemiological studies on endemic diseases and the natural environment in Russia and NIS are scarce and sporadic. However, there have been some studies of the links between health of the population and the geological background. Information on fluorine, iodine, arsenic, selenium, and other elements' behavior in natural environment and their effect on human health is presented in this chapter and is the first attempt to synthesize the interdisciplinary knowledge on some geological factors which affect human health in Russia and NIS. Also anthropogenic factors are mentioned, however, of geological origin.Currently, the most important areas of the study in the field of Medical Geology in Russia - NIS areGeological and geochemical aspects of medical geology in terms of modeling and mapping of the spreading of endemic diseases, toxic elements, such as uranium, fluoride, radon, arsenic, in subsurface, geosphere, and the atmosphere, and its effect on human health.Urban and mining medical geology.Crystal chemistry and crystal genesis of biogenic minerals of different origin.The therapeutic usage of the minerals in terms of biological functions of the elements metals in medicine and industry, and economic minerals in medicine.This chapter, written by leading experts of Russia and NIS, will be of interest to a wide audience of geologists, geochemists, physicians, as well as historians.