Late Cretaceous porphyry Cu and epithermal Cu-Au association in the Southern Panagyurishte District, Bulgaria: the paired Vlaykov Vruh and Elshitsa deposits

Vlaykov Vruh-Elshitsa represents the best example of paired porphyry Cu and epithermal Cu-Au deposits within the Late Cretaceous Apuseni-Banat-Timok-Srednogorie magmatic and metallogenic belt of Eastern Europe. The two deposits are part of the NW trending Panagyurishte magmato-tectonic corridor of central Bulgaria. The deposits were formed along the SW flank of the Elshitsa volcano-intrusive complex and are spatially associated with N110-120-trending hypabyssal and subvolcanic bodies of granodioritic composition. At Elshitsa, more than ten lenticular to columnar massive ore bodies are discordant with respect to the host rock and are structurally controlled. A particular feature of the mineralization is the overprinting of an early stage high-sulfidation mineral assemblage (pyrite ± enargite ± covellite ± goldfieldite) by an intermediate-sulfidation paragenesis with a characteristic Cu-Bi-Te-Pb-Zn signature forming the main economic parts of the ore bodies. The two stages of mineralization produced two compositionally different types of ores—massive pyrite and copper-pyrite bodies. Vlaykov Vruh shares features with typical porphyry Cu systems. Their common geological and structural setting, ore-forming processes, and paragenesis, as well as the observed alteration and geochemical lateral and vertical zonation, allow us to interpret the Elshitsa and Vlaykov Vruh deposits as the deep part of a high-sulfidation epithermal system and its spatially and genetically related porphyry Cu counterpart, respectively. The magmatic-hydrothermal system at Vlaykov Vruh-Elshitsa produced much smaller deposits than similar complexes in the northern part of the Panagyurishte district (Chelopech, Elatsite, Assarel). Magma chemistry and isotopic signature are some of the main differences between the northern and southern parts of the district. Major and trace element geochemistry of the Elshitsa magmatic complex are indicative for the medium- to high-K calc-alkaline character of the magmas. 87Sr/86Sr(i) ratios of igneous rocks in the range of 0.70464 to 0.70612 and 143Nd/144Nd(i) ratios in the range of 0.51241 to 0.51255 indicate mixed crustal-mantle components of the magmas dominated by mantellic signatures. The epsilon Hf composition of magmatic zircons (+6.2 to +9.6) also suggests mixed mantellic-crustal sources of the magmas. However, Pb isotopic signatures of whole rocks (206Pb/204Pb = 18.13-18.64, 207Pb/204Pb = 15.58-15.64, and 208Pb/204Pb = 37.69-38.56) along with common inheritance component detected in magmatic zircons also imply assimilation processes of pre-Variscan and Variscan basement at various scales. U-Pb zircon and rutile dating allowed determination of the timing of porphyry ore formation at Vlaykov Vruh (85.6 ± 0.9Ma), which immediately followed the crystallization of the subvolcanic dacitic bodies at Elshitsa (86.11 ± 0.23Ma) and the Elshitsa granite (86.62 ± 0.02Ma). Strontium isotope analyses of hydrothermal sulfates and carbonates (87Sr/86Sr = 0.70581-0.70729) suggest large-scale interaction between mineralizing fluids and basement lithologies at Elshitsa-Vlaykov Vruh. Lead isotope compositions of hydrothermal sulfides (206Pb/204Pb = 18.432-18.534, 207Pb/204Pb = 15.608-15.647, and 208Pb/204Pb = 37.497-38.630) allow attribution of ore-formation in the porphyry and epithermal deposits in the Southern Panagyurishte district to a single metallogenic event with a common source of metal

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

[Injuries in Floorball: a Questionnaire Survey in Swiss National League A Floorball Players]

BACKGROUND: Rapid changes in direction, acceleration, deceleration and deception manoeuvres with rotational movements increase the risk of injuries in floorball players. Up to date, there are no data or facts available from Swiss Floorball League players demonstrating the types of injuries that occur. This study aimed to find out which injuries occur in Swiss National League A floorball players. SUBJECTS/METHODS: This study was carried out in a retrospective, non- experimental design as a questionnaire survey. Five Swiss National League A floorball teams were interviewed in writing on an exposure period of 12 months. The injury rate describes the number of injuries per 1000 hours of exposure. The Wilcoxon rank sum test was used to assess the significance of the results. The significance level was set to p < 0.05 for all tests. RESULTS: During a calendar year, n = 71 of all players (n = 101) sustained an average of 1.14 injuries (+/- 1.05). The injury rate in the presented data set was 2.01. The injury rate in competition was two times higher than in training (rate ratio (RR) = 2.04). Most injuries were sprains, muscle injuries and inflammation, with muscle injuries almost exclusively affecting the thigh. Sprains usually occurred in the ankle. CONCLUSION: This study confirms the hypothesis that the susceptibility to injuries in floorball is significantly higher during competition compared with training. It can be assumed that players in whom physical activity triggers significant fatigue and emotional stress are more susceptible to injuries. Further studies should be performed to evaluate different preventative measures and to make a comparison on gender-specific vulnerability

Late Cretaceous Cu–Au epithermal deposits of the Panagyurishte district, Srednogorie zone, Bulgaria

This review compiles geological, mineralogical, and isotopic data from the four largest Cu–Au epithermal deposits of the Late Cretaceous Panagyurishte mineral district, Bulgaria, including from north to south: the producing Chelopech, and the past-producing Krassen, Radka and Elshitsa deposits. Epithermal Cu–Au deposits of the northern and older part of this district are mainly hosted by andesites, whereas those from the southern and younger district are hosted by dacites. Advanced argillic alteration is described in the majority of the deposits, with the most complex alteration assemblage occurring at Chelopech. In all deposits, mineralization is the result of replacement and openspace deposition producing massive sulphide lenses surrounded by disseminated mineralization. Additionally at Chelopech, stockwork vein zones are also an important ore type. At Elshitsa, Radka and Krassen, the mineralized zones are controlled by WNW-oriented faults, and at Chelopech there is a supplementary control by NE-oriented faults. A three-stage paragenesis is recognized in all deposits, including an early disseminated to massive pyrite stage; an intermediate, Au-bearing Cu–As–S stage, which forms the economic ore; and a late Zn–Pb–Ba stage. Sulphur isotopic compositions of sulphide and gangue minerals are consistent with similar data sets from other highsulphidation deposits. Variations in Sr and Pb isotope data among the deposits are interpreted in terms of fluid interaction with different host-rocks, additionally variability in Pb isotopic compositions can be attributed to differences in composition of the associated magmatism. Throughout the Panagyurishte district, there is a coherent and continuous sequence of events displayed by the epithermal Cu–Au deposits indicating that they result from similar ore forming processes. However, latitudinal differences in ore deposit characteristics are likely related to emplacements at different depths, differences in degrees of preservation as a function of post-ore tectonics and/or sedimentary processes, efficiency of ore formation, and/or modifications of regional controls during the 14 Ma-long geological evolution of the Panagyurishte district, such as magma petrogenesis and/or tectonic regimes

Aging and yellowing of triterpenoid resin varnishes - Influence of aging conditions and resin composition

The aging of natural triterpenoid resins used as varnishes on paintings is still insufficiently understood. Although progress has been made, questions concerning the aging pathways in light vs. darkness, or the correlation of oxidation with yellowing, remain open. The influence of aging conditions, primarily the amount of light, but also resin composition, on the aging process were investigated. The aging reactions are followed using a variety of mass spectrometric and spectroscopic techniques. Aging processes in dammar and mastic varnishes are shown to be more dynamic and extensive than had generally been believed. In unaged bulk resins, large quantities of radicals develop within weeks after application as a varnish, due to the greatly increased surface-to-volume ratio. This is true for all aging conditions, including aging in darkness, and is accompanied by considerable oxidation as well. After a few months, most of the initial triterpenoids are oxidized. Natural aging in light and darkness leads to the same main aging products. All these findings point to the conclusion that aging largely proceeds by the same pathways in both light and darkness, mainly autoxidation. Without light, enough radicals are formed to maintain extensive autoxidation, although more slowly. Thus, differences between light and dark aging mechanisms are much smaller than often believed. In mastic, the absence of the polymeric constituents is found to enhance oxidation, but reduce yellowing. It appears that the polymer acts as a natural radical stabilizer, favoring the pronounced intrinsic yellowing tendency of mastic. The manipulation of resin composition might lead to improved aging properties of triterpenoid resin varnishe

Incremental growth of mid- to upper-crustal magma bodies during Arabia-Eurasia convergence and collision: A petrological study of the calc-alkaline to shoshonitic Meghri- Ordubad pluton (Southern Armenia and Nakhitchevan, Lesser Caucasus)

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

Trace element diffusion and incorporation in quartz during heating experiments

Abstract Heating of quartz crystals in order to study melt and high-temperature fluid inclusions is a common practice to constrain major physical and chemical parameters of magmatic and hydrothermal processes. Diffusion and modification of trace element content in quartz and its hosted melt inclusions have been investigated through step-heating experiments of both matrix-free quartz crystals and quartz crystals associated with sulfides and other minerals using a Linkam TS1500 stage. Magmatic and hydrothermal quartz were successively analyzed after each heating step for Cu, Al, and Ti using electron probe micro-analyzer. After the last heating step, quartz crystals and their hosted melt inclusions were analyzed by laser ablation inductively coupled plasma mass spectrometry and compared to unheated samples. Heated samples reveal modification of Cu, Li, Na, and B contents in quartz and modification of Cu, Li, Ag, and K concentrations in melt inclusions. Our results show that different mechanisms of Cu, Li, and Na incorporation occur in magmatic and hydrothermal quartz. Heated magmatic quartz records only small, up to a few ppm, enrichment in Cu and Na, mostly substituting for Li. By contrast, heated hydrothermal quartz shows enrichment up to several hundreds of ppm in Cu, Li, and Na, which substitute for originally present H. This study reveals that the composition of both quartz and its hosted melt inclusions may be significantly modified upon heating experiments, leading to erroneous quantification of elemental concentrations. In addition, each quartz crystal also becomes significantly enriched in Cu in the sub-surface layer during heating. We propose that sub-surface Cu enrichment is a direct indication of Cu diffusion in quartz externally sourced from both the surrounding sulfides as well as the copper pins belonging to the heating device. Our study shows that the chemical compositions of both heated quartz and its hosted inclusions must be interpreted with great caution to avoid misleading geological interpretations

Late Cretaceous porphyry Cu and epithermal Cu–Au association in the Southern Panagyurishte District, Bulgaria: The paired Vlaykov Vruh and Elshitsa deposits

ISSN:0026-4598ISSN:1432-186

Porphyry and epithermal deposits in Greece: An overview, new discoveries, and mineralogical constraints on their genesis

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 Reenrichment, 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 byproducts. 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