Petrological studies of the Sakar granitoid batholith (SE Bulgaria) have revealed that rutile-rich aggregates were formed from titanite during albitization and desilification of the granitoid at similar to 600 degrees C and similar to 300 MPa. Titanite conversion to rutile has been tested experimentally. Four experiments involving fluid-aided alteration of titanite in a granitic system were conducted using cold-seal pressure vessels on a hydrothermal line at 280 MPa and 600 degrees C. The starting material included titanite, fluorapatite, and a powdered, unaltered, natural granite from the Sakar Batholith. Four Na-bearing aqueous fluids (NaCl+H2O, NaF+H2O, Na2Si2O5+H2O, and 2 M NaOH) were used. Rutile was formed from titanite in experiments involving NaCl+H2O (RT-1) and NaF+H2O (RT-2). The mineral assemblage formed in RT-1 consisted of rutile, Ti-Th-U oxides, and monazite, whereas in RT-2 rutile, fluorite, lorenzenite, albitized plagioclase, REE-enriched rims on fluorapatite, and a glass formed. Rutile did not form in experiments involving Na2Si2O5+H2O or 2 M NaOH. The comparison between natural observation and the experimental results supports the premise that a NaCl+H2O fluid could have been responsible for the conversion of titanite to rutile during albitization, which further supports the role of NaCl-bearing fluids during the albitization of granitoids in general at mid- to upper-crustal pressures in the presence of alkali-bearing fluids. This implies that the geochemical relationship between rutile and titanite is more a function of the chemistry of the fluid and host rock, especially if they are Na-rich, rather than the P-T conditions. Subsequently, rutile formed from titanite can be used as a geochronometer for dating the process responsible for both the formation of the rutile and the metasomatism of the rock. Detrital rutile is commonly thought to mostly originate from medium- to high-pressure igneous and metamorphic source rocks. Formation of rutile during albitization and desilification of granitoids under relatively high-temperature hydrothermal conditions in the upper crust has implications regarding rutile provenance studies of areas sourced by regionally albitized quartzofeldspathic rocks.

This work reports the first data on the Variscan metamorphic evolution of the Marmarosh/Maramuresh massif in the Outer Eastern Carpathians. Geothermobarometry determinations coupled with U-Th-Pb dating of monazite, apatite, titanite and rutile were used to construct P-T-t paths and refine the geodynamic evolution of the pre-Alpine crystalline basement. These clockwise P-T-t paths evolve from 560-630 MPa and 515-535 degrees C to c. 900-1180 MPa in the north (Ukraine), while in the southern nappe (Romania), the P-T-t conditions evolve from 455-620 MPa and 545-555 degrees C, through to 670-745 MPa and 540-560 degrees C, to 910-965 MPa and 645-660 degrees C. The northernmost nappes were likely structurally lower relative to the southern nappes. Variscan progressive metamorphism related to nappe stacking climaxed at 350-340 Ma, as documented by U-Pb rutile and U-Th-Pb monazite dating.In both regions, post-kinematic exhumation to 700-500 MPa, 550-630 degrees C MPa and then to the titanite stability field was dated at 317-327 Ma, using the U-Pb system on apatite and titanite. Subsequent Permian retrogression and exhumation was constrained to 280-290 Ma by U-Pb rutile and apatite and U-Th-Pb monazite dating. These data link the massif to the external zone of the Central European Variscides. We infer that all Variscan crystalline basement fragments in the Alps and Carpathians probably represent remnants of the same microcontinent, which was dismembered during Alpine orogenesis.

Rare earth element (REE) mineralization has been documented at R & eogon;dziny, located on the eastern margin of the Karkonosze granite (Sudetes, Poland). Minerals of the REE[(As,P)O-4] group with a tetragonal zircontype structure, primarily xenotime-(Y)-chernovite-(Y), Y(PO4)-Y(AsO4) solid solutions, have been identified. These minerals occur as euhedral grains and also as intergrowths with secondary arsenates and silicates, filling cracks, fractures, and voids. Their textural diversity and paragenetic relationships with Ca-, Cu-, Pb-, and Bi-bearing arsenates indicate a crystallization sequence involving successive mineral-forming episodes. Local enrichments in REEs have also been recorded in common supergene arsenates, such as Ca(Pb)-Cu phases including conichalcite (CaCu(AsO4)(OH)) and duftite (PbCu(AsO4)(OH)). Minerals of the xenotime-(Y)-chernovite-(Y) solid solution correspond to intermediate compositions, with the chernovite end-member molar fraction ranging from 0.46 to 0.89. Based on EPMA analyses, yttrium is the dominant cation, accompanied by considerable amounts of middle rare earth elements (MREEs), especially neodymium (up to 12.60 wt.%; 0.21 apfu), samarium (up to 10.39 wt.%; 0.167 apfu), and gadolinium (up to 6.72 wt.%; 0.107 apfu). Some chemical compositions also show a trend towards the gasparite-(LREE) (LREE(AsO4)) compositional field. Xenotime-(Y)-chernovite-(Y) minerals display microporosity, likely resulting from dissolution, metasomatic alteration, and subsequent recrystallization. The REEs at R & eogon;dziny likely originated from both evolved, late-stage hydrothermal fluids and rocks of the metamorphic envelope of the Karkonosze granite, where REEs were mobilized by post-magmatic fluids. Subsequent supergene processes may have further enhanced secondary enrichment.

Allanite-(Sm), the third samariummineral to be discovered, was studied using electronmicroprobe analysis and single-crystal X-ray diffraction. It is isostructural withmonoclinic epidote-supergroup minerals and belongs to the allanite group. The mineral was found in a granitic pegmatite in a serpentine quarry near Jordanow Slaski in Lower Silesia, SW Poland. It occurs as subhedral to anhedral crystals with sizes of up to similar to 150 mu m accompanied by allanite-(Nd), allanite-(Y), clinozoisite, hingganite-(Y), and xenotime(Y). Allanite-(Sm) is yellowish-brown and shows a white streak, a vitreous luster, and a Mohs hardness of similar to 6. It is brittle, with conchoidal fracture and imperfect cleavage. The calculated density is 3.842 g center dot cm(-3), and the calculated mean refractive index is close to 1.737. The holotype crystal contains (in wt %) 33.08(11) SiO2, 0.08(3) TiO2, 21.15(9) Al2O3, 0.45(6) Sc2O3, 0.48 Fe2O3(calc), 0.02(1) V2O3, 2.49(31) Y2O3, 0.18(4) La2O3, 0.95(9) Ce2O3, 0.34(6) Pr2O3, 3.52(31) Nd2O3, 6.12(23) Sm2O3, 0.06(2) EuO, 3.25(21) Gd2O3, 0.34(2) Tb2O3, 0.94(7) Dy2O3, 0.15(4) Ho2O3, 0.16(3) Er2O3, 0.07(6) Tm2O3, 0.06(4) Yb2O3, 0.28(4) MnO, 8.38 FeO(calc), 0.13(2) MgO, 13.71(15) CaO, and 1.95 H2Ocalc(+); the total is 98.04. The empirical EPMA + SREF formula is Al (Ca0.966Mn0.022Fe0.0102+)(Sigma 0.0998) A(2)(Ca-0.372 Sm0.192Y0.121Nd0.114Gd0.098Ce0.032Dy0.028Pr0.011Tb0.010La0.006Er0.005Ho0.004Eu0.002Tm0.002Yb0.002) Sigma(0.998) (Al0.998Al0.998M3)-Al-M1-Al-M2 (Fe(0.628)(2+)Al(0.275)Sc0.036Fe3+0.033Mg(0.018)Ti(0.005)V(0.002)(3+))Sigma 0.998 (T1-T3Si3.012O11)O(OH), the simplified formula is Ca(Sm,REE,Ca)Al2(Fe2+,Al,Fe3+)(Si2O7)(SiO4)O(OH), and the ideal formula is CaSm(Al2Fe2+)(Si2O7)(SiO4)O(OH), which requires (in wt%) SiO2 30.37, Al2O3 17.18, Sm2O3 29.38, FeO 12.11, CaO 9.45, and H2O 1.52; the total is 100. Allanite-(Sm) is monoclinic, space group P2(1)/m, with the following unit-cell parameters: a = 8.8923(6) angstrom, b = 5.7005(3) A, c = 10.1280(8) angstrom, beta = 115.445(9)degrees, V = 463.59(6) angstrom(3), Z= 2, anda:b:c = 1.5599:1:1.7767. The T site is exclusively occupied by Si, the A1 site is occupied by Ca and Mn, and the A2 site is mainly occupied by rare earth elements (REE), of which Sm is dominant. The M1 and M2 sites are occupied by Al and the M3 site by divalent cations, of which Fe2+ characteristic of allanite-type species, is dominant. Allanite-(Sm) and the associated allanite-(Y), allanite(Nd), and hingganite-(Y) are secondary minerals precipitated from Ca-rich hydrothermal fluid during the metasomatic alteration of the Jordan ow Sla.ski pegmatite. They accumulated REE released by the alteration of nearby xenotime-(Y). The disequilibrium rapid crystallization of REE-selective allanite and hingganite phases in an environment strongly enriched in heavy REE (HREE) relative to light REE (LREE), as well as small-scale heterogeneities in REE abundances in the fluid, resulted in the formation of exotic allanite species, including allanite-(Sm).

The Zloty Stok deposit in Central Sudetes hosts nephrite, Fe-As-Au-mineralization and minor W-mineralization. Dolomite-related origin of nephrite is evidenced by low Cr (<14 ppm), Ni (0.4-39.3 ppm) and Co (9.2-71.0 ppm) contents, although the nephrite is unusually rich in Fe2O3 (4.19-14.93 wt%) likely due to an involvement of mafic/ultramafic intrusions in fluids formation. Two subduction-related, coeval, syn- to late-tectonic intrusions suites are adjacent to the deposit, but, of them, only the Klodzko-Zloty Stok pluton was involved in the fluids formation, whereas Jawornik granitoids were uninvolved. A broad span of nephrite F/Cl (55.6-202.3), delta D (-95 parts per thousand to -68 parts per thousand), delta O-18 (delta O-18(tremolite) +3.6 parts per thousand to +10.9 parts per thousand, delta O-18(calcite) +7.0 parts per thousand to +20.4 parts per thousand) and delta Cl-37 (-0.4 parts per thousand to +0.6 parts per thousand) values, reflect a transformation of marbles into skarns and nephrite under three fluid influx events: 1) tremolite, diopside and arsenopyrite precipitation from fluids derived from granitoids of the Klodzko-Zloty Stok pluton (ca. 340 Ma), 2) Fe-enriched tremolite and diopside, talc and lollingite precipitation from fluids, related with clinopyroxenites, gabbros, monzonites, lamprophyres and syenites, of the Klodzko-Zloty Stok pluton (ca. 340 Ma), 3) quartz, calcite and clinozoisite veins formation and precipitation of scheelite, talc and minor tremolite, diopside and arsenopyrite, under the influence of fluids from post-tectonic granitoids of the Klodzko-Zloty Stok pluton (similar to 305 Ma). Nephrite and Fe-As-Au-mineralization preferentially precipitates from hydrothermal fluids when they reach an organic matter-rich horizon in marbles, as evidenced by highly negative delta C-13 values (-16.0 parts per thousand to -9.1 parts per thousand) of calcite from nephrites and skarn, suggesting a crucial role of organic matter in the formation of dolomite-related nephrite deposits.

This study aims to characterize the phase composition and chemistry of the speiss/matte sample from the Metallurgist's Burial at Castillo de Huarmey and to use the information derived from these analyses to infer the temperatures, furnace conditions, and ores associated with the smelting processes, which created the speiss/matte sample. For this purpose, a number of geochemical analyses were performed on the spies/matte fragment: analysis of the general chemical composition (handheld X‐ray fluorescence spectrometry [hhXRF], X‐ray photoelectron spectroscopy [XPS]), analysis of the chemical composition in the micro area (field emission scanning electron microscope with an energy dispersive spectroscopy detector [FE‐SEM‐EDS], field emission electron probe microanalysis [FE‐EPMA]), analysis of the mineral composition (X‐ray diffraction [XRD]), and analysis of the phase composition (Raman spectroscopy). Chemical and mineralogical analyses of the speiss/matte specimen determined that the specimen is composed of distinct arsenide, arsenate, sulfide, and glass phases. During the smelting process, the charge material consisted mainly of Cu, Fe, and As sulfides. Arsenopyrite is the most likely candidate as the mineral source of arsenic. In addition, temperatures of at least 1200°C were achieved during the smelting process, with smelting occurring over a relatively short timeframe given that effective density separation of speiss and matte phases was not achieved.

During a series of high P-T experiments aimed at understanding the hydrothermal alteration of the REE,Ti silicate chevkinite-(Ce), three ThSiO4 phases (thorite, huttonite, and an amorphous ThSiO4 variety) were formed, showing a wide range of textures from small discrete grains to large-scale replacement of the chevkinite-(Ce). All three phases have compositions close to ThSiO4, except that the amorphous type contains small amounts of LREE (<= 0.025 apfu) and inferred H2O. The three different forms have been confirmed by electron backscatter diffraction, which has also provided information on the microstructure of the crystals. The earliest phase to form was huttonite, composed of many randomly oriented microcrystals. This was later replaced by thorite via fluidaided coupled dissolution-reprecipitation. The amorphous type formed both by apparent hydrous alteration of the original crystalline thorite and huttonite. The inferred sequence of events is compatible with thermodynamic constraints on the relative stability of thorite and huttonite.

Seven experiments exploring the reaction of titanite with various hydrothermal solutions have been carried out at 700 °C and 200 MPa for a run duration of 16 days. In experiments involving fluids consisting of NaCl+H2O, KCl+H2O, CaCl2+H2O, 2M NaOH, or 2M KOH, no reaction of the titanite with the fluid was observed other than a slight dissolution of the titanite. Experiments involving NaF+H2O and Ca(OH)2+H2O resulted in visible alteration of the titanite in texture and composition, coupled with the formation of perovskite. In the NaF+H2O experiment, perovskite, enriched with rare earth elements (REE), formed as euhedral to subhedral crystals on the surface of the recrystallized titanite. In the Ca(OH)2+H2O experiment perovskite took in minor amounts of REE, and formed as a reaction rim partially replacing the titanite via a coupled dissolution-reprecipitation reaction. Wollastonite, along with minor calcite, and grossular garnet, formed as an outer rim on the perovskite. In the NaF+H2O experiment major and trace elements were leached from the titanite, whereas in the Ca(OH)2+H2O experiment no leaching of major or trace elements was observed. Nb/Ta, Th/U, and Y/Ho were investigated as potential indicators of hydrothermal processes. While the Nb/Ta ratio was altered in the experimentally metasomatised titanite, the degree of alteration was the same for both fluids. In contrast, only small changes in the Th/U and Y/Ho ratios between the altered and original titanite were seen for either experiment. The formation of perovskite at the expense of titanite in NaF+H2O or Ca(OH)2+H2O fluids demonstrates how titanite reacts with these fluids in simple, low silica activity systems under mid to upper crustal P-T conditions.

Journal Article Evaluating Consensus in Experimental K-ratios from over 40 WDS and EDS Measurement Systems Get access W O Nachlas, W O Nachlas Department of Geoscience, University of Wisconsin, Madison, WI, United States Corresponding author: nachlas@wisc.edu Search for other works by this author on: Oxford Academic Google Scholar A Moy, A Moy Department of Geoscience, University of Wisconsin, Madison, WI, United States Search for other works by this author on: Oxford Academic Google Scholar N Ritchie, N Ritchie National Institute of Standards and Technology, Gaithersburg, MD, United States Search for other works by this author on: Oxford Academic Google Scholar J Donovan, J Donovan CAMCOR, University of Oregon, Eugene, OR, United States Search for other works by this author on: Oxford Academic Google Scholar J H Fournelle, J H Fournelle Department of Geoscience, University of Wisconsin, Madison, WI, United States Search for other works by this author on: Oxford Academic Google Scholar J Allaz, J Allaz Department of Earth Sciences, ETH Zurich, Switzerland Search for other works by this author on: Oxford Academic Google Scholar R Almeev, R Almeev Institute of Mineralogy, Leibniz University Hannover, Germany Search for other works by this author on: Oxford Academic Google Scholar E S Bullock, E S Bullock Earth and Planets Laboratory, Carnegie Science, Washington, DC, United States Search for other works by this author on: Oxford Academic Google Scholar J W DesOrmeau, J W DesOrmeau Department of Geological Sciences & Engineering, University of Nevada, Reno, NV, United States Search for other works by this author on: Oxford Academic Google Scholar K Goemann, K Goemann Central Science Laboratory, University of Tasmania, Hobart, TAS, Australia Search for other works by this author on: Oxford Academic Google Scholar ... Show more R Hoffmann, R Hoffmann Institute for Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, Germany Search for other works by this author on: Oxford Academic Google Scholar P Jokubauskas, P Jokubauskas Faculty of Geology, University of Warsaw, Poland Search for other works by this author on: Oxford Academic Google Scholar N Jöns, N Jöns Institute for Geology, Mineralogy and Geophysics, Ruhr-Universität Bochum, Germany Search for other works by this author on: Oxford Academic Google Scholar T Lam, T Lam Museum Conservation Institute, Smithsonian Institution, Suitland, MD, United States Search for other works by this author on: Oxford Academic Google Scholar A Locock, A Locock Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta, Canada Search for other works by this author on: Oxford Academic Google Scholar D M Ruscitto, D M Ruscitto General Electric Research, Niskayuna, NY, United States Search for other works by this author on: Oxford Academic Google Scholar E P Vicenzi, E P Vicenzi Museum Conservation Institute, Smithsonian Institution, Suitland, MD, United States Search for other works by this author on: Oxford Academic Google Scholar A von der Handt, A von der Handt Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada Search for other works by this author on: Oxford Academic Google Scholar B Wade, B Wade Adelaide Microscopy, The University of Adelaide, Adelaide, SA, Australia Search for other works by this author on: Oxford Academic Google Scholar P Yang, P Yang Department of Earth Sciences, University of Manitoba, Canada Search for other works by this author on: Oxford Academic Google Scholar D Zhang D Zhang Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 225–226, https://doi.org/10.1093/micmic/ozad067.100 Published: 22 July 2023

The Strandja Zone (SE Bulgaria/ NW Turkey) comprises tectonic units affected by Late Jurassic to Early Cretaceous upper greenschist-to amphibolite-facies metamorphism. A contemporaneous tectonothermal event occurred in the Rhodope Metamorphic Complex, which has led to many authors correlating both zones. Three tectonic units can be distinguished in the Bulgarian part of the Strandja Zone: the Sakar, Strandja and Veleka units. This study focuses on albitized rocks of the Sakar Unit that are suspected to be related to this tectono-thermal event. Albitized samples were collected from the Late Carboniferous Sakar Batholith, while for com-parison country-rock orthogneiss unaffected by albitization was also analyzed. Geochemical and petrological studies indicate that albitization was coupled with the removal of quartz and the growth of rutile-rich aggregates replacing titanite. U-Pb rutile dating of an orthogneiss (ca. 154 Ma) confirms Late Jurassic amphibolite-facies conditions, whereas rutile from albitized metagranitoids yields Early Cretaceous ages (ca. 125-116 Ma). Zr-in-rutile thermometry reveals similar crystallization temperatures (similar to 530-620 degrees C) for the albitized Sakar granit-oids and country rock orthogneiss. U-Pb zircon and titanite dating implies a Late Carboniferous crystallization age for various granitoids forming the Sakar Batholith. Our results indicate that at least some parts of the Sakar Unit were affected by thermal events and associated albitization in the Early Cretaceous. However, this did not lead to the formation of a new penetrative fabric, unlike in the Rhodopes, where contemporaneous regional metamorphism is associated with penetrative deformation.

An unusual hydrothermal alteration scheme was presented for chevkinite-(Ce) from the White Tundra pegmatite (2656 ± 5 Ma), Keivy massif, Kola Peninsula. Pb-CO2-rich fluids initially removed REE and Y from the chevkinite-(Ce), with enrichment in Pb and U. PbO abundances reaching 17.35 wt%. Continued alteration resulted in the altered chevkinite-(Ce) being progressively transformed to a Pb-Ti-Fe-Si phase, which proved, upon EBSD analysis, to be almost totally amorphous. Pb enrichment was accompanied by a loss of LREE, especially La, relative to HREE, and the development of strong positive Ce anomalies. A notably U-rich aeschynite-(Y), with UO2 values ≤7.67 wt%, crystallized along with the chevkinite-(Ce). Aeschynite-(Y) with a lower UO2 value (3.91 wt%) and bastnäsite-(Ce) formed during alteration. The formation of bastnäsite-(Ce) rather than cerussite, which might have been expected in a high Pb-CO2 environment, is ascribed to the fluids being acidic.

The White Tundra pegmatites are associated with the Keivy alkali feldspar granite complex in the Kola Peninsula, NW Russia. The host granites are aegirine-arfvedsonite, biotite-arfvedsonite and biotite-ferrohastingsite varieties, ranging compositionally from peralkaline through metaluminous to peraluminous. The pegmatites are remarkable for the diversity of the rare-metal mineralization. The inferred crystallization sequence of the main REE, HFSE and Ti minerals in the pegmatite is: zircon - fergusonite-(Y) - monazite-(Ce) - gadolinite-hingganite series - britholite-(Y) - astrophyllite - titanite - allanite-(Ce) - chevkinite-(Ce) - ilmenite - kainosite-(Y) - REE carbonates. The pegmatites show unusual parageneses indicating a transition of the mineral associations from agpaitic to miaskitic in the same body (e.g. zirconosilicate -> zircon; astrophyllite -> titanite). A number of minerals have anomalous minor element contents. Astrophyllite and some titanites have low (even < 1) Nb/Ta and Zr/Hf ratios that contrast with the overall geochemical environment (ratios >> 1); titanite with very high Y and HREE contents; elevated Sn, W and V contents in some titanosilicates; allanite-(Ce) with very high Ti contents coupled with low (less than stoichiometric) values of Al, suggesting a Ti -> Al substitution. Whole-rock compositions of the host granite show a steady decrease of Nb/Ta and Zr/Hf ratios in peralkaline through metaluminous to peraluminous types. Compositions of Ti minerals suggest that further fractionation of Nb-Ta, Zr-Hf and REE in the White Tundra exotic pegmatite and the crystallization of Ti minerals with anomalous compositions are due to a combination of several factors: assimilation by the primary magma (enriched in Zr, Nb, REE) of upper crustal lithologies enriched in Ta, Hf, LREE, W, Sn; consumption of significant amounts of Nb and Zr by early-crystallized pegmatitic fergusonite and zircon with Nb/Ta and Zr/Hf >> 1; transition of HFSE mineral assemblages in pegmatite from agpaitic to miaskitic with consequent lowering of Nb/Ta and Zr/Hf; crystallization of minerals in a low-temperature (hydrothermal) environment with changing F contents, that promoted a sporadic further decrease of Nb/Ta and Zr/Hf (to values < 1) and increase of Y + HREE. The implications of the fractionation mechanisms for ore-forming processes related to rare-metal granites are discussed.

Gagarinite-(Ce) [Na(Ca,Ce)2F6] has been synthesized as a product in experiments designed to examine the fluid-induced alteration of chevkinite-(Ce). The experiments were conducted at 600 °C and 400 MPa for 21 days and at 550 °C and 200 MPa for 63 days. At 600 °C, a rim of gagarinite-(Ce) was seen to develop around chevkinite-(Ce), which was itself enclosed in a glassy, amorphous material containing inclusions of albite. At 550 °C, the chevkinite-(Ce) was observed to be surrounded by a rim of gagarinite-(Ce) and fluorbritholite-(Ce), which in turn was enclosed in massive narsarsukite with inclusions of albite. This assemblage was associated with a sodic pyroxene. In the 550 °C run both rims with gagarinite-(Ce) were subsequently overgrown by both Ce-bearing frankdicksonite and a lamprophyllite group mineral identified as delindeite. Electron probe microanalyses are given of all reactant phases. The stability conditions of gagarinite-(Ce) are in accord with those inferred from the only natural occurrence, Strange Lake, Canada. The formation of gagarinite-(Ce) is ascribed to NaF being the only component added in the experiments, resulting in a very high Na/Ca ratio in the system. New parageneses for narsarsukite, frankdicksonite, and delindeite are reported.

This manuscript presents results of the newest petrographic, mineralogical and bulk chemical, as well as H, C and O stable isotope study of carbonatites and associated silicate rocks from the Tajno Massif (NE Poland). The Tajno Intrusion is a Tournaisian-Visean ultramafic-alkaline-carbonatite body emplaced within the Paleoproterozoic rocks of the East European Craton (EEC). Carbonatites of the Tajno Massif can be subdivided into the calciocarbonatite (calcite), ferrocarbonatite (ankerite), and breccias with an ankerite-fluorite matrix. Due to location at the cratonic margin and abundance in the REE, Tajno classifies (Hou et al., 2015) as the carbonatite-associated REE deposit (CARD), and more precisely as the Dalucao-Style orebody (the breccia-hosted orebody). High Fe2O3 (13.8 wt%), MnO (2.1 wt%), total REE (6582 ppm), Sr (43895 ppm), Ba (6426 ppm), F (greater than10000 ppm) and CO2 contents points for the involvement of the slab - including pelagic metalliferous sediments - in the carbonatites formation. Spatial relations and Sr isotope composition ((Sr-87/Sr-86)(i) = 0.7043-0.7048; Wiszniewska et al., 2020) of alkali clinopyroxenite and syenite suggest that these are products of differentiation of the magma, generated by the initial melting of the SCLM due to influx of F-rich fluids from subducted marine sediments. Carbonatites Sr isotope composition ((Sr-87/Sr-86)(i) = 0.7037-0.7038), and Ba/Th (16-20620) and Nb/Y (0.01-6.25) ratios, link their origin with a more advanced melting of the SCLM, triggered by CO2-rich fluids from the subducted AOC and melts from sediments. The Tajno Massif - and coeval mafic-alkaline intrusions - age, high potassic composition, and location along the craton margin nearly parallel the Variscan deformation front, are suggesting Variscan subduction beneath the EEC. The oxygen isotope compositions of clinopyroxene (delta O-18 value = 5.2 parts per thousand) and alkali feldspar (delta O-18 value = 5.7 parts per thousand), from alkali clinopyroxenite and foid syenite, respectively, are consistent with mantle-derived magmas. Isotopic compositions of carbonatites and breccias (carbonate delta O-18 = 8.7 parts per thousand to 10.7%0; delta C-13 = -4.8 parts per thousand to -0.4 parts per thousand) span from values of primary carbonatites to carbonatites affected by a fractionation or sedimentary contamination. The highest values (delta O-18 = 10.7 parts per thousand; delta C-13 = -0.4 parts per thousand) were reported for breccia cut by numerous veins confirming post-magmatic hydrothermal alteration. The lowest carbonate delta O-18 (9.3 parts per thousand to 10.7 parts per thousand) and delta C-13 (-5.0 parts per thousand to -3.8 parts per thousand) values are reported for veins in alkali clinopyroxenites, whereas the highest delta O-18 (11.2 parts per thousand) and delta C-13 (-1.2 parts per thousand to -1.1 parts per thousand) values are for veins in syenites and trachytes. Isotopic composition of veins suggests hydrothermal origin, and interaction with host mantle-derived rocks, as well as country rocks. In silicate rocks of the Tajno Massif, fluid influx leads to the development of Pb, Zn, Cu, Ag, Au sulfide mineralization-bearing stockwork vein system, with carbonate, silicate and fluorite infilling the veins. Bulk-rock contents of molybdenum (925 ppm), rhenium (905 ppb) and palladium (29 ppb) are notable. The Re-rich molybdenite association with galena, pyrite and Th-rich bastna spacing diaeresis site in carbonate veins is similar as in Mo deposits associated with carbonatites, implying the mantle source of Mo and Re.

Impurities in paint layers executed with green and blue copper pigments, although relatively common, have been studied only little to date. Yet, their proper identification is a powerful tool for classification of paintings, and, potentially, for future provenance studies. In this paper, we present analyses of copper pigments layers from wall paintings situated in the vicinity of copper ore deposits (the palace in Kielce, the palace in Ciechanowice, and the parish church in Chotków) located within the contemporary borders of Poland. We compare the results with the analyses of copper minerals from three deposits, two local, and one historically important for the supply of copper in Europe, i.e., Miedzianka in the Holy Cross Mountains, Miedzianka in the Sudetes, and, as a reference, Špania Dolina in the Slovakian Low Tatra. Optical (OM) and electron microscopy (SEM-EDS), Raman spectroscopy, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) have been used for a detailed investigation of the minute grains. Special attention has been devoted to antimony and nickel phases, as more unusual than the commonly described iron oxides. Analyses of minerals from the deposits helped to interpret the results obtained from the paint samples. For the first time, quantitative analyses of copper pigments’ impurities have been described.

The chevkinite group of minerals are REE,Ti-silicates increasingly recognized as widespread accessory phases in a wide range of igneous and metamorphic parageneses. Members of the group are here recorded from five localities in Poland: a two-pyroxene andesite from the Kłodzko-Złoty Stok intrusion, a trachyandesite intrusion north of the Pieniny Mountains, a rapakivi-type granite from the Krasnopol intrusion, an anorthosite from the Suwałki Anorthosite Massif, and nepheline syenite from the Ełk syenite massif. Specific members found are chevkinite-(Ce), perrierite-(Ce) and, potentially, the Al-dominant analogue of perrierite-(Ce). The case is made that chevkinite-group minerals will, through systematic investigation, be found in a wide range of Polish igneous and metamorphic rocks.

Allanite is one of the main rare earth elements (REE)-rich accessory minerals in composite dykes from the granitoid pluton of Karkonosze. These dykes differ in composition from the bulk of the pluton by elevated rare earth elements (REE), Y, Zr, and alkali contents, suggesting contribution of an additional component. Allanite exhibits complex alteration textures, which can be divided into two stages. The first stage is represented by allanite mantles, formed by fluid infiltration into previously crystallized magmatic allanite. These zones have low totals, are Ca-, Al-, Mg-, and light REE (LREE)-depleted, and Y-, heavy REE (HREE)-, Th-, Ti-, and alkali-enriched. The fractionation between LREE and HREE was caused by different mobility of complexes formed by these elements in aqueous fluids. The second stage includes recrystallized LREE-poor, Y-HREE-rich allanite with variable Ca, Al, Mg, and REE-fluorocarbonates. The alteration products from both stages demonstrate higher Fe3+/(Fe2+ + Fe3+) ratios and a negative Ce anomaly. These features point to the alkaline, low-temperature, and oxidized nature of the fluids. The differences in mobility and solubility of respective ligands show that the fluids from the first stage may have been dominated by Cl, whereas those of the second stage may have been dominated by F and CO2 (and PO4 in case of one sample). The inferred chemistry of the fluids resembles the overall geochemical signature of the composite dykes, indicating a major contribution of the hydrothermal processes to their geochemical evolution.

Refer to this publication as: Czarniecka, U., Haile, B.G., Braathen, A., Krajewski, K.P., Kristoffersen, M. & Jokubauskas, P. 2020: Petrography, bulk-rock geochemistry, detrital zircon U–Pb geochronology and Hf isotope analysis for constraining provenance: An example from Middle Triassic deposits (Bravaisberget Formation), Sørkappøya, Svalbard. Norwegian Journal of Geology 100, 202017. https://dx.doi.org/10.17850/njg1003-5.