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The Kirazlı mineral district is located at the center of the Biga peninsula metallogenic province, in a geological setting characterized by an extensional tectonic environment. The district hosts a high-sulfidation (HS) ore body with a total reserve of 33.86 Mt @ 0.69 g/t Au and 9.42 g/t Ag within a large-scale hydrothermal alteration. Although the ideal magmatic-hydrothermal models present the spatial and temporal association of HS-epithermal and porphyry Cu deposits, the porphyry Cu potential at the Kirazlı has not been evaluated, yet. Therefore, the mineral-based alteration mapping with the help of SWIR reflectance spectroscopy was carried out. Our study demonstrates that nine different mineral zone have been distinguished and mapped: (1) Silicification, (2) Alunite, (3) Kaolinite, (4) Dickite, (5) Illite, (6) Pyrophyllite, (7) Chlorite, (8) Sericite, and (9) Montmorillonite zones. Collectively, these alterations exhibit a zoned pattern, from central massive silicification to residual silica, NW-SE oriented alunite, and marginal montmorillonite-illite zones within widespread kaolinite – dickite dominated alteration in Kirazlı main zone. The occurrence of pyrophyllite and sericite dominates at the SE of the Kirazlı district, which refers to relative temperature increase. Subsequent drilling confirms the potential for deep prospecting of porphyry Cu mineralization in the region.

Clastic units unconformably overlie the metamorphic basement of the northern and western parts of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria, with suspected late Paleozoic-early Mesozoic depositional ages. In this article, we present new geochemical data and U–Pb detrital zircon geochronology for ten samples from these clastic units. The sedimentary textures are preserved despite the rocks experienced a very-low to low-grade metamorphic overprint. Geochemistry reveals main compositions of arkoses-subarkoses, which have similar trace element and REE characteristics when compared to the Late Carboniferous–Permian and Middle Triassic magmatic bodies in the SASTZ. The source for the sedimentary material derived from acid magmatic rocks of recycled continental arc as demonstrated by tectonic setting discrimination. U–Pb detrital zircon geochronology revealed Late Permian (Lopingian) to Late Triassic (Carnian) maximum depositional ages of the clastic units in the range of 259 Ma to 226 Ma. The main age cluster of Carboniferous zircons (357–301 Ma) is followed in decreasing amount of Permian (298–255 Ma), Ordovician–Silurian (486–419 Ma), Cambrian (542–495 Ma), Neoproterozoic (923–549 Ma) and Triassic (249–226 Ma) age clusters. Few Meso- and Paleoproterozoic (2100–1009 Ma), Neoarchean (2670–2547 Ma) and Devonian (378 Ma and 365 Ma) zircons are present. The prominent clusters of detrital zircons are sourced from the proximal Late Carboniferous–Permian and Middle Triassic magmatic bodies, while Devonian to Cambrian zircons have their source from proximal to distal Ordovician and Cambrian magmatic bodies and the meta-sedimentary protoliths of the SASTZ metamorphic basement, from which inherited Proterozoic–Neoarchean zircons are recycled into the Late Permian to Late Triassic clastic units. The latter are correlated across the northern and western parts of the SASTZ based on their lithology and depositional ages. Most importantly, the main detrital zircon clusters testify for the destruction of the Late Carboniferous–Permian to Middle Triassic magmatic arc system of the SASTZ and related continental-type fluvial–alluvial sedimentation. The provenance from the Cadomian magmatic arc system along the northern periphery of Gondwana is a likely detrital signature for the Neoproterozoic–Cambrian zircons, whereas the provenance of the Mesoproterozoic to Neoarchean detrital zircons might be sought from the Sahara Metacraton and/or Arabian–Nubian Shield in the internal parts of Gondwana. Compared detrital zircon record of the SASTZ is similar to the same record in the adjacent Rhodope and Serbo-Macedonian zones implying a common Paleozoic paleogeographic position, but these zones differ from the detrital record in the Istanbul Zone, also adjacent to the SASTZ.

The Trans-Proteomic Pipeline mass spectrometry data analysis suite has been in continual development and refinement since its first tools PeptideProphet and ProteinProphet were published twenty years ago. The current release provides a large complement of tools for spectrum processing, spectrum searching, search validation, abundance computation, protein inference, and more. Many of the tools include machine-learning modeling to extract the most information from datasets and build robust statistical models to compute the probabilities that derived information is correct. Here we present the latest information on the many TPP tools, and how TPP can be deployed on various platforms from personal Windows laptops to Linux clusters and expansive cloud computing environments. We describe tutorials on how to use TPP in a variety of ways and describe synergistic projects that leverage TPP. We conclude with plans for continued development of TPP.

Late Paleozoic granitoids, meta-granitoids and meta-volcanic rocks predominate in the metamorphic basement of the northern and western parts of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria, together with subsidiaryTriassic rocks of the same nature. Generally, igneous minerals and textures are preserved, except the meta-granitoids and meta-volcanic rocks that experienced a low- to high-grade metamorphic overprint. The volcanic rocks have a peraluminous and high-K calc-alkaline composition, and the granitoids range between I- to S-type compositions, typical of volcanic arcs and syn-collisional settings. LILE and LREE-enrichment and Nb-Ta anomalies characterize the intrusive and extrusive rock suites. U-Pb zircon geochronology has yielded crystallization ages between 245 and 230 Ma for the majority of the studied igneous rocks, and between 297 and 281 Ma for a small group of igneous rocks. Early Permian and Middle Triassic igneous suites of the northern and western SASTZ have similar compositions and a similar tectonic setting when compared to Late Carboniferous-Early Permian intrusive and extrusive suites of the adjacent Sakar unit of the SASTZ, confirming a common regional late Paleozoic-early Mesozoic tectono-magmatic event. As the Late Carboniferous-Permian to Middle Triassic magmatic arc components extend across the SASTZ, they trace the time-correspondent active continental margin along the Eurasian plate during subduction of the Paleotethys oceanic lithosphere. The late Paleozoic Eurasian active continental margin magmatic arc evolution of the SASTZ can be linked with the Serbo-Macedonian-Rhodope zones to the southwest, where coeval meta-granitoids document the same geodynamic context. By contrast, the Triassic igneous suite of the SASTZ is unrelated to the Serbo-Macedonian-Rhodope zones, where Triassic meta-ophiolite and meta-granitoids record Neotethys rifting.

The trace element composition of zircon, especially in tandem with U-Pb geochronology, has become a powerful tool for tracing magmatic processes associated with the formation of porphyry copper deposits. However, the use of the redox-sensitive Eu and Ce anomalies as a potential mineral exploration proxy is controversial. This study presents a comprehensive, temporally constrained data set of zircon trace element compositions (n = 645) for three compositionally distinct magmatic series identified in the Meghri-Ordubad pluton, southernmost Lesser Caucasus. The 30 million years of Cenozoic magmatism in the Meghri-Ordubad pluton are associated with several ore-forming pulses leading to the formation of porphyry copper deposits and epithermal-style mineralization. Our zircon geochemical data constrain the thermal and chemical evolution of this complex intrusive suite and allow an evaluation of the usefulness of zircon as a mineral exploration proxy for porphyry copper deposits. Our results combined with Rayleigh fractionation modeling indicate that the trace element composition of zircon (Th/U, Hf, Ti, YbN/DyN, Eu anomalies) is influenced by the composition and the water concentration of the parental magma, as well as by co-crystallizing titanite and apatite. In contrast, the variations of Ce anomalies remain difficult to explain by magmatic processes and could rather be ascribed to relative fluctuations of the redox conditions. In the Meghri-Ordubad pluton, we do not observe any systematic patterns between the trace element composition in zircons and the different ore-forming pulses. This questions the reliability of using the trace element composition in zircon as an exploration mineral proxy, and it rather emphasizes that a good knowledge of the entire magmatic evolution of a metallogenic province is required.

The Zangezur-Ordubad mining district of the southernmost Lesser Caucasus is located in the central segment of the Tethyan metallogenic belt and consists of porphyry Cu-Mo and epithermal Au and base metal systems hosted by the composite Cenozoic Meghri-Ordubad pluton. Ore-hosting structures and magmatic intrusions are predominantly confined to a central N-S–oriented corridor 40 km long and 10 to 12 km wide, located between two regional NNW-oriented right-lateral faults, the Khustup-Giratagh and Salvard-Ordubad faults. The anatomy and kinematics of the main fault network are consistent with dextral strike-slip tectonics controlled by the NNW-oriented Khustup-Giratagh and Salvard-Ordubad faults. Dextral strike-slip tectonics was initiated during the Eocene, concomitantly with final subduction of the Neotethys, and controlled the emplacement of the Agarak, Hanqasar, Aygedzor, and Dastakert porphyry Cu-Mo and Tey-Lichkvaz and Terterasar epithermal Au and base metal deposits. The Eocene structures were repeatedly reactivated during subsequent Neogene evolution in transition to a postsubduction geodynamic setting. Ore-bearing structures at the Oligocene world-class Kadjaran porphyry Cu-Mo deposit were also controlled by dextral strike-slip tectonics, as well as porphyry mineralization and its epithermal overprint hosted by an early Miocene intrusion at Lichk. Eocene to early Miocene dextral strike-slip tectonics took place during NE- to NNE-oriented compression related to Paleogene Eurasia-Arabia convergence and subsequent Neogene postcollision evolution. Paleostress reconstruction indicates major reorganization of tectonic plate kinematics since the early Miocene, resulting in N-S– to NW-oriented compression. Early Miocene epithermal overprint at the Kadjaran porphyry deposit and left-lateral reactivation of faults and mineralized structures are linked to this late Neogene tectonic plate reorganization.

Introduction The Tethyan mountain ranges stretch from northwestern Africa and western Europe to the southwest Pacific Ocean and constitute the longest continuous orogenic belt on Earth. It is an extremely fertile metallogenic belt, which includes a wide diversity of ore deposit types formed in very different geodynamic settings, which are the source of a wide range of commodities mined for the benefit of society (Janković, 1977, 1997; Richards, 2015, 2016). There are other ore deposit types in this segment of the Tethyan metallogenic belt that are not covered in this special issue, such as bauxite and Ni laterite deposits (Herrington et al., 2016), ophiolite-related chromite deposits (Çiftçi et al., 2019), sedimentary exhalative and Mississippi Valley-type deposits (Palinkaš et al., 2008; Hanilçi et al., 2019), or deposits related to surficial brine processes (Helvacı, 2019).

The Kapan mining district in the southernmost Lesser Caucasus is one of the few locations along the central Tethyan metallogenic belt where ore-forming processes were associated with magmatic arc growth during Jurassic Tethys subduction along the Eurasian margin. Three ore deposits of the Kapan district were investigated in this study: Centralni West, Centralni East, and Shahumyan. The ore deposits are hosted by Middle Jurassic andesitic to dacitic volcanic and volcaniclastic rocks of tholeiitic to transitional affinities below a late Oxfordian unconformity, which is covered by calc-alkaline to transitional Late Jurassic-Early Cretaceous volcanic rocks interlayered with sedimentary rocks.The mineralization consists of veins, subsidiary stockwork, and partial matrix replacement of breccia host rocks, with chalcopyrite, pyrite, tennantite-tetrahedrite, sphalerite, and galena as the main ore minerals. Centralni West is a dominantly Cu deposit, and its host rocks are altered to chlorite, carbonate, epidote, and sericite. At Centralni East, Au is associated with Cu, and the Shahumyan deposit is enriched in Pb and Zn as well as precious metals. Both deposits contain high-sulfidation mineral assemblages with enargite and luzonite. Dickite, sericite, and diaspore prevail in altered host rocks in the Centralni East deposit. At the Shahumyan deposit, phyllic to argillic alteration with sericite, quartz, pyrite, and dickite is dominant with polymetallic veins, and advanced argillic alteration with quartz-alunite ± kaolinite and dickite is locally developed.The lead isotope composition of sulfides and alunite (206Pb/204Pb = 18.17–18.32, 207Pb/204Pb = 15.57–15.61, 208Pb/204Pb = 38.17–38.41) indicates a common metal source for the three deposits and suggests that metals were derived from magmatic fluids that were exsolved upon crystallization of Middle Jurassic intrusive rocks or leached from Middle Jurassic country rocks. The δ18O values of hydrothermal quartz (8.3–16.4‰) and the δ34S values of sulfides (2.0–6.5‰) reveal a dominantly magmatic source at all three deposits. Combined oxygen, carbon, and strontium isotope compositions of hydrothermal calcite (δ18O = 7.7–15.4‰, δ13C = −3.4−+0.7‰, 87Sr/86Sr = 0.70537–0.70586) support mixing of magmatic-derived fluids with seawater during the last stages of ore formation at Shahumyan and Centralni West.40Ar/39Ar dating of hydrothermal muscovite at Centralni West and of magmatic-hydrothermal alunite at Shahumyan yield, respectively, a robust plateau age of 161.78 ± 0.79 Ma and a disturbed plateau age of 156.14 ± 0.79 Ma. Re-Os dating of pyrite from the Centralni East deposit yields an isochron age of 144.7 ± 4.2 Ma and a weighted average age of the model dates of 146.2 ± 3.4 Ma, which are younger than the age of the immediate host rocks. Two different models are offered, depending on the reliability attributed to the disturbed 40Ar/39Ar alunite age and the young Re-Os age. The preferred interpretation is that the Centralni West Cu deposit is a volcanogenic massive sulfide deposit and the Shahumyan and Centralni East deposits are parts of porphyryepithermal systems, with the three deposits being broadly coeval or formed within a short time interval in a nascent magmatic arc setting, before the late Oxfordian. Alternatively, but less likely, the three deposits could represent different mineralization styles successively emplaced during evolution and growth of a magmatic arc during a longer time frame between the Middle and Late Jurassic.

The average contents F = 788 ppm and Cl < 45 ppm of the clay fraction from Amazon River mouth sediments represent the composition of a large portion of weathered South American continental crust prior to any contact with high salinity formation waters. The data show a large fractionation between F and Cl with the latter being strongly leached during weathering along with Na and Ca. The one-order-of-magnitude fractionation is com- parable to Cl fractionation from degassing during early Earth accretion. In contrast, F is strongly retained in the hydroxyl sites of neoformed clay minerals, mainly illite, as well as in detrital apatite and muscovite. The high average ratio F/Cl > 10 of the clay fraction from Amazon River sediments are comparable only to Cl-poor MORB and evolved granite and rhyolite. The high content Cl = 180 ppm and low F/Cl = 3 of average shale is due to interaction of the sediments with high salinity diagenetic fluids. The Seridó schist belt is used to assess the behavior of F and Cl during shale metamorphism and anatexis. Its ratio F/Cl > 10 ppm is high compared to average shale and is related to the strong partitioning of Cl into metamorphic fluids. The obtained data suggest that the Cl partitioned into shales during diageneses is released back into fluids produced during metamorphic conditions. The experimental data indicate that anatexis of mica schist significantly fractionates F/Cl ratios producing schist residue with F/Cl > 38 and peraluminous melts with F/Cl = 6.

In Senegal, the environmental impact of artisanal small-scale gold mining (ASGM) using mercury (Hg) is poorly documented despite its intensification over the past two decades. We report here a complete dataset including the distribution and speciation of Hg in soil, sediment, and water in pristine and ASGM impacted sites of the Gambia River ecosystem (Kedougou region - eastern Senegal). Selective extraction showed that soils surrounding ASGM activities were contaminated with elemental Hg [Hg(0)] at concentrations up to 3.9 mg kg−1. In the Gambia River, high total Hg (THg: 1.16 ± 0.80 mg kg−1) and methylmercury (MeHg: 3.2 ± 2.3 ng g−1) were also measured in sediment samples collected at ASGM sites. Along the stream, THg concentrations in sediment decrease with distance from the ASGM sites, while those of methylmercury increase downstream. The study of THg and MeHg partitioning between filtered surface water and suspended particles demonstrate that particulate transport is responsible for the downstream dissemination of the Hg contamination from ASGM sites. Sedimentation of fine particles enriched in Hg downstream ASGM sites likely favors MeHg production and accumulation in sediment. Although elemental Hg is weakly labile, surface soil erosion may also provide important and long-term Hg inputs to downstream aquatic ecosystems, where it can be oxidized and methylated. Finally, the dissemination of THg and MeHg downstream from the ASGM sites in the Gambia River may constitute a long-term source of contamination and can have a large scale impact on the aquatic ecosystem through biomagnification.

Greece hosts a variety of magmatic-hydrothermal ore deposits/prospects with porphyry- and epithermal styles playing a major role in its total gold endowment. These deposit types are mainly clustered in two areas, the Rhodope- and Attico-Cycladic massifs, and formed from about 33 Ma to the Pleistocene, as a result of back-arc extension in the Aegean Sea, metamorphic core complex formation, and contemporaneous post-subduction and arc magmatism. In the Serbo-Macedonian massif, porphyry Cu-Au deposits include Skouries, Fisoka, Tsikara, Vathi and Gerakario. Causative intrusives are Oligocene to Miocene granodiorites to monzonites. Gold and PGE mineralization is associated with potassic alteration of the intrusives. In the eastern Rhodope massif and the NE Aegean islands, porphyry prospects occur at Pagoni Rachi, Konos Hill, Myli, Melitena (west Thrace), Fakos, Sardes, and Kaspakas (Limnos island) and Stypsi (Lesvos island). Mineralization is associated with Oligocene to Miocene subvolcanics of calc-alkaline to shoshonitic affinity. Feature of these prospects, which they share in common with several porphyry Au-only systems, is their shallow depth of emplacement, the presence of potassic/sodic-calcic and/or phyllic alteration, a strong epithermal overprint, their low Cu content, an extreme Re-enrichment, the multistage introduction of Au, the presence of banded quartz veinlets, and the local presence of tourmaline. New discoveries of porphyry-style mineralization at King Arthur, St. Philippos and Aisymi, increases the gold potential in west Thrace. High-intermediate sulfidation epithermal Au-Ag polymetallic deposits/prospects overprint and/or occur laterally from porphyry-style mineralization, where they are spatially associated with lithocaps of advanced argillic alteration. High-intermediate sulfidation Au-Ag epithermal mineralization at Perama Hill, Mavrokoryfi and Pefka in west Thrace, and at Pterounda, Mesotopos and Megala Therma on Lesvos island is controlled by steeply-dipping extensional faults within volcanic rocks, without any obvious genetic relationship to spatially-related porphyry-style mineralization. Polymetallic epithermal deposits and prospects contain critical and energy critical metals (e.g., Te, Se, Bi, Sb, In, Ge and Ga), which may be considered as by-products. In the Attico-Cycladic area, porphyry Mo-W mineralization occurs as sheeted quartz veins and stockworks cutting a potassic- to sericitic-altered Miocene granodiorite stock in the Lavrion district. Bonanza grade Au- and/or Ag-rich veins with epithermal affinities crosscut metamorphic rocks at Lavrion, and on Syros, Tinos, Antiparos and Anafi islands. Milos island is characterized by shallow submarine volcanic-hosted IS-HS epithermal Au-Ag-Te and base metal deposits. Antimony-As-Ag-Au deposits/prospects on Chios, Samos and Kos islands in the eastern Aegean Sea, indicate the potential for Carlin-style mineralization in Greece. Several factors played a role to the metal endowment of the Aegean porphyry-epithermal systems: magma fertility in the source regions, depth of emplacement of causative intrusives, relative contribution of mantle versus crustal material, redox state of subduction-related magmas, and physico-chemical fluid conditions at the site of ore deposition.

The magmatic arcs of the Eastern Pontides and Lesser Caucasus lie in continuation from one another. A comparison of the subduction related magmatic rocks outcropping throughout this segment of the Northern Tethyan belt exhibits chronological disparities, questioning the common subduction history of the Eastern Pontides and the Lesser Caucasus regions. New data and observations including geochronological and geochemical data, relative to subduction to collision related magmatic rocks argues a novel paleogeographic reconstruction illustrating Mesozoic and Cenozoic evolution of this region. Jurassic to Early Cretaceous arc magmatism runs mainly from the Sochi-Ritsa/Bechasyn regions (Greater Caucasus) towards the south-east to the Alaverdi region and further into the Lesser Caucasus. Late Cretaceous and Cenozoic arc magmatism is evidenced throughout the Eastern Pontides extending through the Bolnisi region to the Lesser Caucasus arc. East to west, Jurassic to Early Cretaceous and Late Cretaceous to Cenozoic portions of arc split to the north and south of the Eastern Black Sea, respectively. Throughout Cretaceous subduction, this segment of the magmatic arc of the Southern Eurasian margin was torn in two due to the oblique opening of the Eastern Black Sea as a back- to intra-arc basin, from west to east. This reconstitution implies that the Jurassic-Early Cretaceous subduction related magmatic rocks of the Greater Caucasus are remnant potions of the Eastern Pontides and Lesser Caucasus arcs. This infers the emplacement of subduction to collision related magmatic rocks throughout the Mesozoic and Cenozoic along the entire Southern Eurasian margin is solely due to a single long-lasting north-dipping subduction.

Palaeozoic granitoids and meta-granitoids dominate the metamorphic basement of the Sakar unit of the Sakar-Strandzha Zone (SASTZ) in southeast Bulgaria. In this article, we present new wholerock geochemical data and U–Pb zircon geochronology for the Sakar unit granitoids. The igneous minerals and textures are preserved, except the meta-granitoids that experienced a weak amphibolite-facies overprint. Geochemistry reveals compositions of peraluminous high-K calc-alkaline Ito S-type granitoids of volcanic arc origin. A major group of LILE-LREE-enriched granitoids and meta-granitoids and a single HFSE-HREE-enriched meta-granitoid are distinguished. U–Pb geochronology has yielded crystallization ages between 305 and 295 Ma for the major group granitoids and a ca. 462 Ma crystallization age of HFSE-HREE-enriched meta-granitoid. Late Palaeozoic granitoids of the Sakar unit show similar compositions and a similar tectonic setting when compared to other granitoids of the SASTZ, confirming a uniform region-wide tectonomagmatic event. As the Late Carboniferous-Permian magmatic arc components extend across the SASTZ, they trace the time-correspondent active continental margin along the Eurasian plate during subduction of the Palaeotethys oceanic lithosphere. The late Palaeozoic Eurasian active continental margin magmatic arc evolution of the SASTZ can be extended into the Serbo-Macedonian-Rhodope zones to the west, where time equivalent meta-granitoids support the same geodynamic context.

The composite Meghri-Ordubad pluton (MOP) is located in the southernmost Lesser Caucasus and outcrops over ~1000 km2 in southern Armenia and Nakhitchevan. It is characterized by nested intrusions incrementally emplaced over ~30 Myr from the Middle Eocene to Early Miocene, coeval with the closure of the Neotethyan Ocean and the regional Arabia-Eurasia continental collision. We recognize three compositionally distinct intrusive series in the MOP: a medium- to high-K calc-alkaline series 1 dominated by gabbro, quartz diorite and tonalite, a shoshonitic to high-K calc-alkaline series 2 including gabbro, monzogabbro, monzodiorite, monzonite and syenite, and a high-K calc-alkaline adakitic series 3 characterized by the emplacement of lamprophyre dikes followed by porphyritic granodioritic intrusions and dikes. Thermobarometry calculations together with detailed petrography, mineral chemistry and experimental mineral stability P-T diagrams indicate a polybaric crystallization history and magma emplacement at mid- to upper crustal levels (0.1-0.3 GPa). Mineral textures and compositions reveal open-system magmatic processes such as mafic magma replenishment and reactivation of crystal mushes prior to transport towards shallower crustal levels in the MOP. The evolution of magma chemistry (calc-alkaline vs shoshonitic) and mineral assemblages (amphibole-bearing vs amphibole-free) indicate fluctuation in primary melt alkali and water contents over time. Such chemical evolution is ascribed to a decrease in the degree of partial melting of a chemically heterogeneous, but isotopically homogeneous, mantle source. Overall, the MOP is characterized by the successive emplacement of hydrous magma batches in the mid- to upper crust and petrological processes that were dominated by fractional crystallization (± crustal assimilation) upon cooling and, or, decompression (± degassing). We propose a new temporal and spatial petrogenetic model for the MOP, encompassing three long-lived, chemically distinct magmatic series incrementally assembled over 30 Myr within a pre-, syn- and post-collisional geodynamic setting.

We modeled non-steady-state, fluid-assisted diffusion in a sheet plane, infinite cylinder and finite thin cylinder using analytical solutions of the diffusion equation and the experimental diffusivity of F-in-biotite. Diffusion experiments on natural biotite in the presence of hydrofluoric acid at 0.4 GPa and 650, 700, and 750 °C produced diffusive influx perpendicular to the c-axis. EPMA mapping and profiling allow us to define the following Arrhenius expression of F diffusion in biotite: D = 7.04 m 2 s × 10 − 4 × exp − 221 kJ mol RT − 1 The results yield the discrimination of a high-T homogenization domain where cooling paths continuously reequilibrate F-in-biotite, an intermediate-T zonation domain where cooling paths record F-in-biotite diffusion profiles and a low-T closure domain where F-in-biotite remains unchanged. The zonation domain significantly expands with increasing cooling rates and decreasing diffusion time. We systematically analyzed F-in-biotite with electron microprobe in samples collected along representative cross-sections within the Serido Belt, northeastern Brazil. Its metasedimentary units reached upper amphibolite grade metamorphic conditions, with constant F-in-biotite (F ≈ 0.33 wt.%) in grains from mica schist and paragneiss. The Ti-in-biotite geothermometer yielded nearly constant temperatures around 623 °C. The F-in-biotite regional background values remain unchanged at the contact with the major Ediacaran F-rich Acari pluton. It indicates the absence of magmatic fluid influx into the host rocks and is evidence for a fluid-absent nature of melts. By contrast, the F-in-biotite of the metric mica schist enclaves within dykes and sills of Cambrian pegmatitic granites was reequilibrated by interaction with exsolved fluids. The Ti-in-biotite geothermometer indicates temperatures around 642 °C, and our model suggests 100 kyr as a minimal duration for fluid-rock interaction. The preservation of intra-grain F-in-biotite homogeneity requires fluid flux cessation before cooling or fluid-present cooling rates below 100 °C Myr−1. Higher cooling rates would generate F-in-biotite intra-grain zonation. At the contact with the pegmatitic granites, the metasedimentary rocks show meter-scale F-in-biotite gradients due to thermal profiles setting the fluid (fH2O/fHF) gradient. The preservation of such gradients is related to a relatively fast fluid flux episode compared to the overall duration of the elevated thermal profile. The absence of intra-grain zonation indicates that F-in-biotite re-equilibration was fast relative to that of the fluid flux duration. We found intra-grain F-in-biotite zonation within an orthogneiss sample from the Paleoproterozoic Caico complex basement nearby the metasedimentary belt and intruded plutons. The fit of the natural profile by modeled profiles for cooling rates below 10 °C Myr−1, obtained from available Serido Belt U-Pb and 40Ar/39Ar ages, indicates that the orthogneiss cooled from 475 °C. It suggests the existence of a thermal gradient as the inner part of the belt cooled from 623 °C.

Three magmatic series of substantially different ages and compositions were successively emplaced to form the composite Meghri–Ordubab pluton (MOP) in the southernmost Lesser Caucasus. The protracted incremental assembly during 30 Myr, from Middle Eocene to Early Miocene, renders this location particularly suitable to characterize the petrogenetic evolution of Cenozoic magmatism during the final stage of the Neotethyan subduction. Based on whole-rock geochemistry, two main transitions tightly constrained in time are recognized. The first transition from Middle Eocene medium-K calc-alkaline to Late Eocene–Middle Oligocene shoshonitic magmatism corresponds to a marked increase in LREE and MREE and more juvenile 87 Sr/ 86 Sr and 143 Nd/ 144 Nd ratios. The second transition to Late Oligocene–Early Miocene high-K calc-alkaline “adakite-like” magmatism is coeval with a marked increase in Mg#, and Ni and Cr contents together with a depletion in MREE and HREE. Although the three differentiation series are derived from lower to mid-crustal hydrous magma fractionation, temporal variations of the magmatic source conditions are required to explain the contrasting chemistry of the parental magmas over time. Medium-K calc-alkaline parental magmas were generated by high degree of partial melting (~ 15%) of a garnet lherzolite. The shoshonitic and adakitic magmatic series represent magmas produced by low degree (1–5%) of partial melting of a garnet lherzolite, but a higher amount of residual garnet is required to reproduce the "adakite-like" signature. The timing of the two main geochemical transitions in the MOP is correlated with a progressive evolution from a compressional to an extensional stress regime linked to (1) the final stage of the Neotethyan subduction followed by the Arabia–Eurasia continental collision during the Eocene–Oligocene, and (2) the transition toward post-collisional magmatism, combined with a switch toward transcurrent tectonics during the Late Oligocene–Early Miocene.

In the Aegean sector of the Alpine orogen of the Eastern Mediterranean, the Sakar-Strandzha Zone (SSZ) represents a major tectonic unit that straddles the territories of Bulgaria and Turkey. The westernmost part of the SSZ in Bulgaria includes the area along the Maritsa river valley and the St. Iliya Heights, both connected through several small outcrop areas under the Cenozoic sedimentary cover. In Bulgaria, the Triassic felsic magmatism along the Maritsa river valley was inferred by Chatalov (1961) on the basis of the stratigraphy, but only a single U-Pb zircon age revealed Early Triassic (ca. 249 Ma) felsic magmatism in the SSZ of Turkey (Aysal et al., 2018). Here, we constrain the timing of Triassic magmatism using U-Pb LA-ICP-MS zircon geochronology of felsic magmatic bodies in the western part of the SSZ in Bulgaria.A sample from a (meta) rhyolite body yielded a concordant age of 237.8 ± 3.4 Ma, which confirmed a crystallization likely concomitant with the deposition of the Triassic clastic rocks in the northern Maritsa river valley. To the east along the valley, a leucocratic granite body located south of the Permian Sakar batholith (ca. 295-296 Ma, Bonev et al., 2019), yielded a concordant age of 242.1 ± 1.8 Ma for the crystallization, having crosscutting relationships with the high-grade metamorphic basement. A leucocratic and K-feldspar porphyric meta-granite bodies yielded concordant ages of 243.3 ± 5.8 Ma and 240.6 ± 2.3 Ma, respectively, for the crystallization within the so-called Harmanli block to the south along the valley. At St. Iliya Heights a sample from the Prochorovo Formation (meta) rhyolite body yielded a concordant age of 245.4 ± 1.5 Ma for the crystallization, which implies an Early Triassic age of the clastic rocks with which it inter-fingers. In the area between the Maritsa river valley and the St. Iliya Heights at the village of Svetlina a leucocratic meta-granite body yielded a concordant age of 229.6 ± 2.4 Ma. The concordantly dated zircons that yielded Triassic ages of the igneous/meta-igneous protoliths all have Th/U ratios compatible with the magmatic process. The major elements of the dated samples reveal calc-alkaline to high-K-alkaline peraluminous felsic compositions similar to the adjacent Late Carboniferous-Permian igneous/meta-igneous rocks of the SSZ.The U-Pb zircon ages reveal Early-Middle Triassic magmatic phase (ca. 245-230 Ma) in the western SSZ of Bulgaria. These age data provide a regional-scale temporal link for the Triassic magmatism extending to the easternmost extremity of the SSZ in Turkey. The Triassic continental type felsic magmatism in the western SSZ is interpreted to result from the ongoing Paleotethyan subduction under the Eurasian plate, which magmatism follows the development of a Late Carboniferous-Permian continental magmatic arc of the SSZ (Bonev et al., 2019).ReferencesAysal, N., Şahin, S.Y., Güngör, Y., Peytcheva, I., Öngen, S., 2018. Journ. Asian Earth Sci., 164, 83-103.Bonev, N., Filipov, P., Raicheva, R., Moritz, R., 2019. Int. Geol. Rev., 61, 1957-1979.Chatalov, G., 1961. Compt. Rend. Acad. Bulg. Sci., 14, 503-506.Acknowledgements: The study was supported by the NSF Bulgaria DN04/6 contract.

We investigated the Sakar unit metamorphic rocks of the Sakar–Strandzha zone in Bulgaria, using 40Ar/39Ar dating of amphibole from the polymetamorphic basement and white mica in the overlying upper Permian metasedimentary rocks of the Paleokastro Formation. The amphibole and white mica revealed plateau ages of 140.50 ± 1.75 Ma and 126.19 ± 1.29 Ma, respectively, indicating an Early Cretaceous cooling history of the regional amphibolite-facies metamorphism to greenschist-facies conditions. Similar metamorphic grades and cooling histories of the Sakar unit share evidence with the nearby Rhodope Massif for the northern Aegean region-wide early Alpine tectonometamorphic event.

The Bolnisi district is a distinct tectonic zone of the Lesser Caucasus, which is considered to represent the eastern extremity of the Turkish Eastern Pontides. Late Cretaceous, low-K, calc-alkaline to high-K rhyolite of the Mashavera and Gasandami Suites is the predominant rock type of the district, and is accompanied by subsidiary dacite, and rare high-alumina basalt and trachyandesite of the Tandzia Suite. The Mashavera and Gasandami rhyolite and dacite have yielded U-Pb LA-ICP-MS and TIMS zircon ages between 87.14 ± 0.16 and 81.64 ± 0.94 Ma, which are in line with the Coniacan-Santonian ages of radiolarian fauna of the Mashavera Suite. The felsic rocks of the Mashavera and Gasandami Suites were deposited during a ~6.6 m.y.-long silicic magmatic flare-up event, which together with the Tandzia Suite mafic rocks, documents Late Cretaceous bimodal magmatism in an extensional tectonic setting. Trace element data indicate that high Y-Zr, low- to high-silica rhyolite and dacite, and low Y-Zr high-silica rhyolite have been erupted, respectively, from coeval deep and shallow crustal reservoirs. The rocks of the bimodal magmatic event are overlain by high-K volcanic rocks of the Campanian Shorsholeti Suite, which have been erupted during slab roll-back and steepening, from magmas produced by deep melting of a metasomatised mantle. Eocene postcollisional felsic intrusions crosscut the Late Cretaceous rock. The Coniacian to early Campanian bimodal magmatism, and the subsequent high-K magmatism of the Bolnisi district are contemporaneous and share geochemical characteristics with the Late Cretaceous magmatism of the Eastern Pontides. It documents the existence of a Late Cretaceous regional silicic magmatic province, and subsequent high-K magmatism during slab steepening. This regional magmatic evolution coincided with the opening of the Black Sea and the Adjara-Trialeti basins. This evolution was coeval with the wanning stages of northern Neotethyan subduction, after a ~40 m.y.-long magmatic lull along the southern Eurasian convergent margin. Early Eocene adakite-like magmatism affected both the Bolnisi district and the Eastern Pontides, demonstrating a common postcollisional magmatic evolution.

Four porphyry Cu-Mo systems were investigated by Re-Os molybdenite geochronology to constrain their timing with respect to the geodynamic and magmatic evolution of the eastern Pontides, Turkey. Molybdenite from the Ispir-Ulutaş deposit yielded an Re-Os age of 131.0 ± 0.7 Ma, which is consistent with Early Cretaceous U-Pb laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon ages of local calc-alkaline intrusions. It demonstrates that porphyry deposits were already formed during Early Cretaceous subduction of the Neotethys along the eastern Pontides, and that they can be correlated with porphyry Cu events in the adjacent Lesser Caucasus. Molybdenite Re-Os ages of 76.0 ± 0.4 and 75.7 ± 0.4 Ma at the Elbeyli prospect and 77.2 ± 1.0 Ma at the Emeksen prospect overlap with U-Pb LA-ICP-MS zircon ages of shoshonitic to high-K calc-alkaline intrusions in the region, which were emplaced during Late Cretaceous Neotethys subduction. A 50.7 ± 0.3 Ma molybdenite Re-Os age at the Güzelyayla deposit confirms porphyry Cu-Mo emplacement coeval with Eocene postcollisional, calc-alkaline adakitic magmatism of the eastern Pontides.An electron microprobe study of molybdenite samples, supplemented by data obtained during Re-Os dating, shows that the Eocene Güzelyayla deposit and the Late Cretaceous Emeksen prospect have the highest Re enrichment. Postcollisional melting of a thickened mafic lower continental crust and melting of a metasomatized lithospheric mantle with little to no interaction with upper crustal rocks may explain the Re enrichment at Güzelyayla and Emeksen, respectively.

The PA +/- narbaAYA +/- Mo-Cu prospect is hosted within the PA +/- narbaAYA +/- intrusion, which is exposed together with the NW-SE-trending Koyunoba, Egrigoz, and Baklan plutons along the northeastern border of the Menderes massif. The PA +/- narbaAYA +/- intrusion predominantly comprises monzonite, porphyritic granite, and monzodiorite. All units of the PA +/- narbaAYA +/- intrusion have sharp intrusive contacts with each other. The principal mineralization style at the PA +/- narbaAYA +/- prospect is a porphyry-type Mo-Cu mineralization hosted predominantly by monzonite and porphyritic granite. The porphyry type Mo-Cu mineralization consists mostly of stockwork and NE- and EW-striking sub-vertical quartz veins. Stockwork-type quartz veins hosted by the upper parts of the porphyritic granite within the monzonite, are typically enriched in chalcopyrite, molybdenite, pyrite, and limonite. The late NE- and EW-striking normal faults cut the stockwork vein system and control the quartz-molybdenite-chalcopyrite-sphalerite-fahlore-galena veins, as well as molybdenite-hematite-bearing silicified zones. Lithogeochemical and whole-rock radiogenic isotope data (Sr, Nd and Pb) of the host rocks, together with Re-Os molybdenite ages (18.3 +/- 0.1 Ma - 18.2 +/- 0.1 Ma) reveal that the monzonitic and granitic rocks of the PA +/- narbaAYA +/- intrusion were derived from an enriched lithospheric mantle-lower crust during Oligo-Miocene post-collisional magmatism. The lithospheric mantle was metasomatised by fluids and subducted sediments, and the mantle-derived melts interacted with lower crust at 35-40 km depth. This mechanism explains the Mo and Cu enrichments of the PA +/- narbaAYA +/- intrusion during back-arc magmatism. We conclude that the melt of the PA +/- narbaAYA +/- intrusion could have rapidly ascended to mid-crustal levels, with only limited crustal assimilation along major trans-lithospheric faults as a result of thinning of the middle to upper crust during regional extension, and resulted in the development of porphyry-style mineralization during the early Miocene (similar to 18 Ma). The subsequent exhumation history of the Mo-Cu-bearing PA +/- narbaAYA +/- intrusion is attributed to regional-scale uplift, and further exhumation along detachment faults of the associated core complexes during the middle to late Miocene.

This study focuses on the Elbeyli-Ordu, Emeksen-Giresun, Guzelyayla-Trabzon and Uluta-Ispir porphyry-type prospects located in the Eastern Pontides, Turkey. Our new LA-ICP-MS U-Pb zircon age data reveal that the Elbeyli-Ordu Mo-Cu mineralization is hosted by a 77.0 +/- 1.3 Ma-old monzonite/monzodiorite with a shoshonitic character. The Emeksen Mo mineralization, located similar to 40 km southeast of the Elbeyli-Ordu prospect, consists of NW- and NE-striking quartz veins crosscutting a high-K calc-alkaline to shoshonitic granite dated at 78.5 +/- 0.8 Ma, a granodiorite dated at 78.7 +/- 05 Ma and porphyry granite dated at 77.7 +/- 0.5 Ma. The Guzelyayla porphyry Cu-Mo prospect consists of a stockwork-type Cu-Mo mineralization crosscutting a calc-alkaline 81.4 +/- 1.1 Ma-old dacite porphyry and Late Cretaceous calc-alkaline andesite. The Ispir-Ulutas mineralization is hosted within a highly sericitized 131.1 +/- 0.9 Ma-old quartz-porphyry that intruded into a 132.9 +/- 0.6 Ma-old calc-alkaline granite porphyry. Our new U-Pb zircon ages, lithogeochemical and radiogenic isotopic data of the host rocks associated with the porphyry-type prospects in the Eastern Pontides indicate that they formed in an arc-related environment during Cretaceous subduction of the Neotethys Ocean, and the Ispir-Ulutas prospect is attributed to the main stage of the northward subduction of the Neotethys during the Early Cretaceous. We conclude that the Guzelyayla and Emeksen hydrothermal systems were formed during a transitional compressional to extensional tectonic evolution, whereas the Late Cretaceous Elbeyli hydrothermal system was emplaced during an extensional arc magmatic event. Highly-oxidized, high-K calc-alkaline to shoshonitic magmas at Emeksen and Elbeyli were derived from a metasomatized, heterogeneous and enriched lithospheric mantle, with variable degrees of partial melting of the mantle wedge and variable crustal contamination. Mixing/mingling processes between mafic magmas derived from the lower crust and acidic magmas at upper crustal levels played an important role in the formation of Cu-Mo porphyry-type mineralization in the Eastern Pontides. (C) 2016 Elsevier B.V. All rights reserved.

The Shamlugh polymetallic deposit located in the Alaverdi mining district, Armenia is hosted by Middle Jurassic magmatic rocks of the Somkheto-Karabakh island arc, Lesser Caucasus. Lithogeochemistry and radiogenic isotope geochemistry indicate a subduction setting with an evolution from tholeitiic to transitional Middle Jurassic magmatism to calc-alkaline to high-K/shoshonitic Late Jurassic magmatism. A progressively more juvenile mantellic input in the magmatic source is noted. Ore consists of stratabound massive sulfide ore bodies, ore-bearing breccia, stockwork-style mineralization and disseminated ore hosted by a pyroclastic host rock unit below a subvolcanic rhyolitic sill. Towards depth, the stratabound ore is connected to subvertical high-grade sulfide veins hosted by basaltic andesitic, andesitic and dacitic tuff and lava breccia. Ore minerals include principally pyrite and chalcopyrite with minor sphalerite and hematite. Hydrothermal alteration consists of quartz, chlorite, carbonate and sericite in the footwall pyroclastic rock, tuff and lava breccia, which are also crosscut by late stage carbonate and barite veins. The rhyolitic sill has been affected by silicification and sericite alteration, and contains rare sulfides. Sulfur isotope values for sulfides range from +0.7 to +4.6 ‰, and suggest an essentially magmatic source for sulfur. Strontium isotopic compositions of hydrothermal carbonates and sulfates (0.70507 - 0.70660), sulfur isotopes of sulfates (+16.8 to +17.3 δ34S ‰ VCDT) and carbon and oxygen isotopic compositions of late stage carbonates (δ18O: +15.9 to +17.6 ‰ VSMOW; δ13C: -1.8 to -0.8 ‰ VPDB) are permissive with seawater incursion in the ore-forming hydrothermal system, but can also be attributed to fluid-rock interaction with hidden metamorphic basement rocks and Jurassic magmatic rocks. The lead isotopic composition of sulfides (206Pb/204Pb: 18.505 to 18.586, 207Pb/204Pb: 15.611 to 15.636, 208Pb/204Pb: 38.516 to 38.640) implies leaching of the Middle Jurassic host rocks as the main source of metals. LA-ICP-MS U-Pb zircon dating of the hanging wall rhyolitic sill affected by hydrothermal alteration yielded an age of 155.0 ± 1.0 Ma, and provides a maximum age for mineralization. Ore formation at Shamlugh is younger than the immediate Middle Jurassic host rocks and is related to the Late Jurassic calc-alkaline and high-K/shoshonitic magmatic evolution. Late Jurassic magmatism includes a tonalite dated by LA-ICP-MS U-Pb zircon geochronology at 152.9 ± 0.7 Ma that hosts the 146 Ma-old Teghout porphyry deposit. In the absence of other age constraints, the genetic relationship of the polymetallic Shamlugh deposit with the Teghout porphyry deposit remains open to question. Nevertheless, hydrothermal opaque mineral and alteration paragenesis, and the lithologically and structurally controlled ore body geometry at Shamlugh are consistent with a low to intermediate sulfidation epithermal model.

We focused on the Pirin–Pangeon–Thasos carbonate sequence of the Rhodope thrust system, combining Sr isotopes from marble with U–Pb dating of detrital zircons from interlayered schists with outcrop near the villages of Ilindentsi and Petrovo in Bulgaria. The youngest zircon age at Ilindentsi is 266 Ma, i.e. Middle Permian, while the youngest zircon at Petrovo yielded an age of 290 Ma, i.e. Early Permian. Strontium isotopes range from 0.707420 to 0.707653, and are consistent with a Middle Permian maximum depositional age. Middle Permian sedimentation of this carbonate platform most likely occurred along the Eurasian margin rather than the Gondwana margin.

We present field, chemical and U–Pb age data for metamafic–ultramafic bodies of the Triassic rift-related Therma–Volvi–Gomati (TVG) complex of the Serbo-Macedonian Massif (SMM) in the northern Aegean region. The TVG rocks record igneous textures overprinted by Alpine metamorphism and deformation. The high-Ti Volvi body was transformed into amphibolites, which also rim the low-Ti Gomati and Nea Roda bodies. The compositions are compatible with normal (N-) and enriched (E-) mid-ocean ridge basalt (MORB) and weak ocean island basalt (OIB) signatures of the high-Ti rocks, whereas the low-Ti rocks are depleted with respect to MORB, suggesting melt extraction from a mantle source. U–Pb geochronology reveals Triassic crystallization of the Volvi body at 240 Ma. Ordovician to Carboniferous xenocrystic zircons were found in the Stratoni body of the TVG complex, which were sampled from the SMM basement. The Triassic Arnea rift-related metagranite intrudes the Volvi body. Comparison of the compositions of the Volvi body and the Arnea metagranite of the SMM with Triassic metagranite of the Rhodope Massif (RM) supports the presence of a regional bimodal rift suite. The location of the TVG complex at the SMM–RM margin of Eurasia confirms its origin as a Middle Triassic rift suite, and its nature as a continental margin ophiolite representing an ocean–continent transition of the propagating Neotethys. Supplementary material: Whole-rock chemical analyses and U–Pb geochronology analytical results data tables are available at https://doi.org/10.6084/m9.figshare.c.4087022 Thematic collection: This article is part of the ‘Tethyan ophiolites and Tethyan seaways collection9 available at: https://www.lyellcollection.org/cc/tethyan-ophiolites-and-tethyan-seaways

Zunyite is a rare F- and Cl- bearing mineral related to advanced argillic alteration zones of porphyry/epithermal style mineralization and is considered as a pathfinder mineral towards high-grade Au ores. We report here the first occurrence of zunyite along with alunite, quartz, APS minerals, diaspore, pyrophyllite and kaolinite in the metallogenic province of Western Thrace. The Konos Hill prospect in Western Thrace comprises a telescoped porphyry Mo-Re-Cu-Au system, overprinted by high-sulfidation mineralization. In low topographic levels, porphyry-style mineralization is exposed and comprises pyrite-chalcopyrite-bornite-molybdenite-rheniite-bearing quartz-stockwork. Host rocks are subvolcanic bodies of granodioritic composition that have suffered pervasive sericitic alteration. High-sulfidation epithermal-style alteration occupies the higher topographic levels and has caused significant overprinting of the porphyry-style mineralization and alteration. It consists of silicified zones related to N-S and E-W trending faults, which grade outwards to advanced argillic alteration assemblages. These assemblages are characterized by abundant alunite and quartz, with minor presence of diaspore, APS minerals, kaolinite, pyrophyllite and zunyite. Zunyite forms euhedral crystals that reach in size up to 300μm. They sometimes include minor quartz and are associated with alunite, APS minerals and pyrophyllite. EPMA data revealed variations in the F and Cl content of zunyite, that range between 3.62-6.54 wt.% and 2.65-3.15 wt.% respectively. Alunite supergroup minerals display a wide compositional range and are represented by members of the alunite, beudanite and plumbogummite subgroups. Alunite and natroalunite constitute the most common advanced-argillic alteration minerals and are found in both quartz+zunyite and quartz+diaspore+pyrophyllite assemblages. Available mineral-chemical data favor the existence of compositions that cover a complete solid-solution series between Na- and K-rich varieties. Common mode occurrences comprise euhedral, tabular-shaped and rarely pseudocubic crystals. APS minerals are usually found as pseudocubic crystals forming the cores of tabular alunites. Analyzed compositions comprise woodhouseite (Sr-, Ce- and Sr-Ce- rich members were found). Diaspore forms aggregates of euhedral, coarse-grain crystals scattered in strongly silicified rock. Finally, pyrophyllite when present, forms acicular aggregates in the matrix along with diaspore and quartz. Available data suggest that the formation of the studied advanced argillic alteration assemblages is hypogene and due to ascending magmatic fluids released by the subvolcanic bodies. Mineralogical variances in the different assemblages may reflect distinct degrees of hydrothermal alteration. Co-existence of zunyite, APS minerals and pyrophyllite could be used to set constraints on the physicochemical conditions of formation of the assemblage, as the volatile-rich nature of the minerals reflects a narrow range of pH and temperature in hydrothermal systems.

Economically important porphyry Cu-Mo deposits (PCDs) are generally hosted by upper-crustal plutons of variable chemical compositions related to distinct geodynamic settings. The absolute timing and duration of pluton assembly and PCD formation are critical to understanding the genetic relationship between these interrelated processes. Here, we present new comprehensive zircon U-Pb and molybdenite Re-Os ages that tightly constrain the timing and duration of pluton assembly and the age of mineralization in one of the largest ore-bearing plutons of the central Tethyan metallogenic belt, the Meghri-Ordubad pluton, southern Armenia and Nakhitchevan, Lesser Caucasus. This composite pluton was incrementally assembled during three compositionally distinct magmatic episodes over ∼30 m.y., comprising Middle Eocene (48.9–43.1 Ma) calc-alkaline subduction-related magmatism lasting 5.8 ± 0.8 m.y., followed by postsubduction Late Eocene–Middle Oligocene (37.8–28.1 Ma) shoshonitic magmatism over 9.7 ± 0.9 m.y., and Late Oligocene–Early Miocene (26.6–21.2 Ma) adakitic magmatism consisting of shoshonitic dikes and high-K calc-alkaline granodioritic magmas emplaced over 5.4 ± 0.4 m.y. Despite the distinct geodynamic settings and magma compositions, each intrusive suite culminated in the formation of variably sized PCDs, including the giant Oligocene Kadjaran porphyry Cu-Mo deposit associated with high-Sr/Y shoshonitic magmas. Complementary in situ zircon hafnium (eHfzircon = +8 to +11.3) and oxygen (δ18Ozircon = +4.6‰ to +6.0‰) isotope data support a mantle-dominated magma source with limited crustal contribution and/or cannibalization of young and juvenile lower-crustal cumulates. We conclude that, independent of geodynamic setting and magma composition, long-lived (5–10 m.y.) incremental mantle-derived magmatism is a prerequisite to form fertile magmatic-hydrothermal systems, and especially giant PCDs.

The Konos Hill prospect in NE Greece represents a telescoped Mo⁻Cu⁻Re⁻Au porphyry occurrence overprinted by deep-level high-sulfidation mineralization. Porphyry-style mineralization is exposed in the deeper parts of the system and comprises quartz stockwork veins hosted in subvolcanic intrusions of granodioritic composition. Ore minerals include pyrite, molybdenite, chalcopyrite, and rheniite. In the upper part of the system, intense hydrothermal alteration resulted in the formation of a silicified zone and the development of various advanced argillic alteration assemblages, which are spatially related to N⁻S, NNW⁻SSE, and E⁻W trending faults. More distal and downwards, advanced argillic alteration gradually evolves into phyllic assemblages dominated by quartz and sericite. Zunyite, along with various amounts of quartz, alunite, aluminum phosphate⁻sulfate minerals (APS), diaspore, kaolinite, and minor pyrophyllite, are the main minerals in the advanced argillic alteration. Mineral-chemical analyses reveal significant variance in the SiO2, F, and Cl content of zunyite. Alunite supergroup minerals display a wide compositional range corresponding to members of the alunite, beudantite, and plumbogummite subgroups. Diaspore displays an almost stoichiometric composition. Mineralization in the lithocap consists of pyrite, enargite, tetrahedrite/tennantite, and colusite. Bulk ore analyses of mineralized samples show a relative enrichment in elements such as Se, Mo, and Bi, which supports a genetic link between the studied lithocap and the underlying Konos Hill porphyry-style mineralization. The occurrence of advanced argillic alteration assemblages along the N⁻S, NNW⁻SSE, and E⁻W trending faults suggests that highly acidic hydrothermal fluids were ascending into the lithocap environment. Zunyite, along with diaspore, pyrophyllite, and Sr- and Rare Earth Elements-bearing APS minerals, mark the proximity of the hypogene advanced argillic alteration zone to the porphyry environment.

Native iron has been identified in an active thermogenic travertine deposit, located at Ilia area (Euboea Island, Greece). The deposit is forming around a hot spring, which is part of a large active metallogenetic hydrothermal system depositing ore-bearing travertines. The native iron occurs in two shapes: nodules with diameter 0.4 and 0.45 cm, and angular grains with length up to tens of &mu, m. The travertine laminae around the spherical/ovoid nodules grow smoothly, and the angular grains are trapped inside the pores of the travertine. Their mineral-chemistry is ultra-pure, containing, other than Fe, only Mn (0.34&ndash, 0.38 wt.%) and Ni (&le, 0.05 wt.%). After evaluating all the possible environments where native iron has been reported up until today and taking under consideration all the available data concerning the study area, we propose two possible scenarios: (i) Ilia&rsquo, s native iron has a magmatic/hydrothermal origin i.e., it is a deep product near the magmatic chamber or a peripheral cooling igneous body that was transferred during the early stages of the geothermal field evolution, from high temperature, reduced gas-rich fluids and deposited along with other metals in permeable structural zones, at shallow levels. Later on, it was remobilized and mechanically transferred and precipitated at the Ilia&rsquo, s thermogenic travertine by the active lower temperatures geothermal fluids, (ii) the native iron at Ilia is remobilized from deep seated ophiolitic rocks, originated initially from reduced fluids during serpentinization processes, however, its mechanical transport seems less probable. The native iron mineral-chemistry, morphology and the presence of the other mineral phases in the same thermogenic travertine support both hypotheses.

In the Hellenides of northern Greece, the Kassandra–Sithonia and Central Chalkidiki ophiolites constitute the Vardar suture zone against the Serbo-Macedonian margin of Eurasia. The mafic-intermediate to acid members in the crustal section of the Kassandra–Sithonia ophiolites have N- and E-MORB signatures compatible with an origin in a back-arc spreading center. The MORB mantle source has received subduction zone input from the nearby Paikon arc system as revealed by LILE and LREE enrichments. A diorite from the Gerakini complex presumably belonging to the Central Chalkidiki ophiolites shows more enriched HFSE and REE patterns relative to MORB and Na-rich character compared to the Kassandra–Sithonia ophiolites. The Sithonia ophiolite crystallization spans from 159 to 149 Ma, and the Gerakini complex diorite crystallized at 173 Ma as derived from new U–Pb zircon geochronology. The main cluster of Permo-Carboniferous, a small cluster of Neoproterozoic–Cambrian and few Proterozoic, Ordovician, Devonian, Triassic and Middle Jurassic inherited zircons derive from the Serbo-Macedonian margin units. Thus, a Late Jurassic ca. 10 Ma lasting igneous accretion of the Kassandra–Sithonia back-arc crust within the eastern Vardar zone is now well constrained and corroborated by Berriasian–Early Valanginian supra-ophiolite cover limestones. Instead of an affinity to the Central Chalkidiki ophiolites, the Gerakini diorite exhibits chemical similarity to the Chortiatis arc magmatic suite of the Circum-Rhodope belt within the eastern Vardar zone. The Gerakini diorite predates the Sithonia ophiolite in which the Chortiatis arc suite supplied Middle Jurassic inherited zircons. The Chortiatis arc compared with arc-related Evros ophiolites of the Circum-Rhodope belt in Thrace region shows the same 173–160 Ma life span and tectonic setting, implying the extension of the arc systems across the north Aegean Sea. Based on these new temporal constraints, a tectonic scenario of Jurassic subduction settings and arc/back-arc systems development in the Maliac and Vardar oceanic basins is proposed that also accounts for continental magmatism in the Serbo-Macedonian margin of Eurasia.

Over > 40 years of implementation of the International Geoscience Programme (IGCP), a partnership and flagship programme between UNESCO and the International Union of Geological Sciences (IUGS), UNESCO realized that the involvement of Africa both in terms of projects devoted to the continent and leadership, was marginal. Between 2011 and 2013, UNESCO collaborated with the Swedish International Development Cooperation Agency (Sida) to support capacity-building activities aiming to increase the participation of Africa in IGCP. From this exercise, two projects (UNESCO/Sida IGCP-594 and IGCP-606) emerged as a research networking platform between scientists from Africa and Europe on the environmental and health challenges of mining activities in Africa. At the end of their implementation, the two projects jointly prepared and published a Special Issue on “Impacts of mining and mineral processing on the environment and human health in Africa” in the Journal of Geochemical Exploration in 2014 edited by Kříbek et al. (2014). However, it was obvious that the challenges facing African countries as a result of mining activities go well beyond simple IGCP projects, and need extensive mobilisation in terms of human re- sources, laboratory facilities and fund raising. The success of two major IGCP projects (IGCP-594 and IGCP-606) encouraged UNESCO to enter into a new Programme Cooperation Agreement with Sida for the period 2014–2018 to support an expanded project entitled “Mapping and Assessing the Environmental and Health Impacts of Abandoned Mines in Sub- Saharan African Countries”. The project aimed to reduce the adverse effects of mining activities on the ecosystem and health of adjacent communities while, at the same time, promote a peaceful mining atmosphere among industry, authorities and local communities. An important advancement in the mining sector is the legal ob- ligation for mining companies to rehabilitate former operational mine sites and ensure that they are restored to a safe environmental state after the mine is closed. While this concept is well rooted in mining legislation in many developed countries, this is not always the case in developing countries, especially in Sub-Saharan Africa. Apart from poor environmental governance as highlighted in the Africa Mining Vision, many African countries lack a precise inventory and assessment of abandoned and derelict mines. It is therefore important to make an assessment of the true extent of the detrimental effects of metal and metalloid pollutants and their impact on human and animal health, as well as on ecosystems. This is a pre-requisite for appropriate legislation development and enforcement. This new project intended to provide crucial scientific knowledge that will contribute to understanding of the factors that control cycling of pollutants from abandoned mines in soils, water and vegetation and the impact on the food chain. Development of appropriated technologies to mitigate environmental risk associated with mining activities was also at the heart of the project. Furthermore, influencing policies, training, education and awareness focusing on communities involved or living around mine sites were important aspects of the project. We anticipate that the results of the project will be used to improve the environmental norms in individual countries in Sub-Saharan Africa and the efficiency of governments in addressing the challenges related to the adverse effects of abandoned mines. The new project builds on a strong network of > 100 scientists working on 29 sites in 17 African countries, with focus on field assessment of pollution (soil, water, crops, health of human and animals), rehabilitation of degraded ecosystems, and policy issues for the attention of communities and governments. For the monitoring of the project, UNESCO put in place a scientific board composed of international experts in this field, some of whom have served as Co-Guest Editors of this Special Issue. An important meeting took place in April 2018 in Nairobi, Kenya, where all project leaders met with the members of the scientific board to evaluate the progress of the project. A key resolution by participants of this meeting was the preparation of another Special Issue to avail the new research contributions to the scientific community.

A detailed field and petrographic study constrains the volcanic evolution and environment setting of the volcano-sedimentary-hosted Chelopech Cu–Au epithermal deposit, Bulgaria. Magmatic activity and associated high-sulfidation epithermal mineralization occurred at about 91 Ma in the Panagyurishte ore district of the Eastern European Banat–Timok–Srednogorie metallogenic belt. Volcanic and hydrothermal activity took place in a complex subaqueous setting, resulting in the intercalation of quartz sandstone with andesitic volcanic and volcaniclastic breccia. There are also hypabyssal andesite intrusion, phreatomagmatic breccia and interbeds of pyroclastic, oolithic and bioclastic rocks. The presence of altered cerebroid ooid-bearing sedimentary units characteristic of salty environment is in accordance with a lagoon environment predating the mineralization at Chelopech. Four principal stages of evolution for the Chelopech district are proposed based on field and petrographic observations. Initial volcanism occurred in a lake or in a coastal, shallow lagoon environment above crystalline basement. The Chelopech “phreatomagmatic” breccia and subsurface andesites were emplaced at this time. Subsequent hydrothermal activity produced the different hydrothermal breccia types, advanced argillic and quartz–phyllic alteration, and Au–Cu vein and replacement mineralization. The end of volcanism and hydrothermal activity was associated with opening of a pull-apart basin that covered the Chelopech environment with a sedimentary flysch. Tertiary compression faulting juxtaposed various rocks and tilted the ore deposit during the Alpine orogeny.

The polymetallic Cu–Au–Ag–Zn ± Pb, Cu–Au and Cu deposits in the Kapan, Alaverdi and Mehmana mining districts of Armenia and the Nagorno–Karabakh region form part of the Tethyan belt. They are hosted by Middle Jurassic rocks of the Lesser Caucasus paleo-island arc, which can be divided into the Kapan Zone and the Somkheto–Karabakh Island Arc. Mineralization in Middle Jurassic rocks of this paleo-island arc domain formed during the first of three recognized Mesozoic to Cenozoic metallogenic epochs. The Middle Jurassic to Early Cretaceous metallogenic epoch comprises porphyry Cu, skarn and epithermal deposits related to Late Jurassic and Early Cretaceous intrusions. The second and third metallogenic epochs of the Lesser Caucasus are represented by Late Cretaceous volcanogenic massive sulfide (VMS) deposits with transitional features towards epithermal mineralization and by Eocene to Miocene world-class porphyry Mo–Cu and epithermal precious metal deposits, respectively. The ore deposits in the Kapan, Alaverdi and Mehmana mining districts are poorly understood and previous researchers named them as copper–pyrite, Cu–Au or polymetallic deposits. Different genetic origins were proposed for their formation, including VMS and porphyry-related scenarios. The ore deposits in the Kapan, Alaverdi and Mehmana mining districts are characterized by diverse mineralization styles, which include polymetallic veins, massive stratiform replacement ore bodies at lithological contacts, and stockwork style mineralization. Sericitic, argillic and advanced argillic alteration assemblages are widespread in the deposits which have intermediate to high-sulfidation state mineral parageneses that consist of tennantite–tetrahedrite plus chalcopyrite and enargite–luzonite–colusite, respectively. The ore deposits are spatially associated with differentiated calc-alkaline intrusions and pebble dykes are widespread. Published δ 34 S values for sulfides and sulfates are in agreement with a magmatic source for the bulk sulfur whereas published δ 34 S values of sulfate minerals partly overlap with the isotopic composition of contemporaneous seawater. Published mineralization ages demonstrate discrete ore forming pulses from Middle Jurassic to the Late Jurassic–Early Cretaceous boundary, indicating time gaps of 5 to 20 m.y. in between the partly subaqueous deposition of the host rocks and the epigenetic mineralization. Most of the described characteristics indicate an intrusion-related origin for the ore deposits in Middle Jurassic rocks of the Lesser Caucasus, whereas a hybrid VMS–epithermal–porphyry scenario might apply for deposits with both VMS- and intrusion-related features. The volcanic Middle Jurassic host rocks for mineralization and Middle to Late Jurassic intrusive rocks from the Somkheto–Karabakh Island Arc and the Kapan Zone show typical subduction-related calc-alkaline signature. They are enriched in LILE such as K, Rb and Ba and show negative anomalies in HFSE such as Nb and Ta. The ubiquitous presence of amphibole in Middle Jurassic volcanic rocks reflects magmas with high water contents. Flat REE patterns ([La/Yb] N = 0.89–1.23) indicate a depleted mantle source, and concave-upward (listric-shaped) MREE–HREE patterns ([Dy/Yb] N = 0.75–1.21) suggest melting from a shallow mantle reservoir. Similar trace element patterns of Middle Jurassic rocks from the Somkheto–Karabakh Island Arc and the Kapan Zone indicate that these two tectonic units form part of one discontinuous segmented arc. Similar petrogenetic and ore-forming processes operated along its axis and Middle Jurassic volcanic and volcanosedimentary rocks constitute the preferential host for polymetallic Cu–Au–Ag–Zn ± Pb, Cu–Au and Cu mineralization, both in the Somkheto–Karabakh Island Arc and the Kapan Zone.

This study describes Hg-resistant bacterial present in the aquatic sediments artisanal small-scale gold mining ASGM activities along Gambia River Kedougou, Senegal. Mercury (Hg) is used for gold amalgamation in artisanal small-scale gold mining (ASGM) activities. The level of total Hg in sediment samples was determined by automatic mercury analyser. Bacterial (colony-forming units) susceptibility to Hg was evaluated by minimal inhibitory concentrations. The phylogenetic diversity analysis of the Hg-resistant bacteria was performed by PCR amplification of 16S rDNA on isolated bacterial strains, followed by restriction fragment length polymorphism, cloning and sequencing. The results documented high concentrations of Hg in ASGM activity areas ranging from 2.4 to 6.2 mg kg-1. Population densities of heterotrophic bacteria in wet sediment ranging from 3.7 × 106 to 4.6 × 108 CFU g−1. The isolated bacterial strains from highly Hg-contaminated sites can grow to medium containing up to 17 mg L−1 of Hg2+. In this study, bacterial strains resistant to Hg are Stenotrophomonas maltophilia, Dyella ginsengisoli, Arthrobacter defluvi, Arthrobacter pascens, Bacillus firmus and Pseudomonas moraviensis. Our results demonstrate the occurrence the presence of diverse groups of bacterial strains resistant to metal (Hg) under tropical conditions. The isolated strains are particularly interesting for further studies to evaluate their role in bioremediation of Hg in contaminated aquatic ecosystems.