The potential of heavy minerals as a provenance tracer in Albian arenites of extra-Carpathian Poland was assessed. Studies in this area have focused on various methods based on heavy mineral chemistry that provide an effective tool for reconstructing the provenance of quartz-rich sediments. The previously suggested division of the study area into two domains with different source areas: the western domain – the Miechów area, and the eastern domain – the Lublin area, was based on geochronological (monazite and muscovite dating) and rutile mineral chemical studies. The mineral chemistry of newly examined heavy minerals supports the previously suggested division. The mineral chemistry of detrital tourmaline suggests medium-grade metamorphic rocks as the main source in both domains. Detrital garnet in the western domain shows affiliation to the Góry Sowie Massif, while garnet in the eastern domain was most probably sourced from southern/central Norway. The western domain was most probably fed from rocks of the Bohemian Massif. The main source area for the eastern domain was most probably located in the Baltic Shield. The distinct division of the study area into two domains was caused by the palaeogeography of the region in the Albian and the action of longshore currents in south-eastward and eastward directions. Supplementary Material 1 Supplementary Online Material 2
Abstract Gorerite, ideally CaAlFe 11 O 19 is a new mineral and M -type hexaferrite of the magnetoplumbite group. It was found in ferrite-rich segregations of esseneite–gehlenite–wollastonite–anorthite melted rock of the ‘olive’ subunit of pyrometamorphic rocks located near Hatrurim Junction in the Negev Desert, Israel. Within these ferrite-rich segregations up to 100 μm in size, platy crystals of gorerite up to 50 μm in size intergrow with hibonite, hematite, maghemite, magnesioferrite, dorrite, barioferrite and andradite, forming aggregates. Additionally, small crystals of gorerite occur within magnesioferrite. Importantly, gorerite did not crystallise directly from the melt. Instead, it emerged through a reaction involving earlier crystallised hibonite and an iron-enriched melt, resulting in the partial or complete replacement of hibonite by gorerite. Gorerite appears grey in the reflected light ( R = 18–23%), displaying distinct bireflectance: dark-grey perpendicular to Z and light-grey parallel to Z . Its Raman spectrum exhibits only one strong band at 700 cm –1 , which shifts to higher frequencies with increasing Al content. Gorerite crystallises in the P 6 3 / mmc space group, with lattice parameters a = 5.8532(4) Å, c = 22.7730(2) Å and V = 675.67(7) Å 3 with Z = 2. It exhibits a structure characterised by an intercalation of triple spinel-like S blocks and rock-salt type R blocks along the hexagonal c -axis.
A complex palaeomagnetic, rock-magnetic and mineralogical study of ultrabasic rocks from the Sowie Góry Block (GSB) and Jordanów–Gogołów Serpentinite Massif (JGSM) revealed the presence of several components of natural remanent magnetization (NRM). The authors found three groups of Palaeozoic as well as Triassic and Recent components of the geomagnetic field. The Palaeozoic components of NRM are carried mainly by magnetite of several generations formed during several serpentinization episodes. Permo-Carboniferous component (A1) present overall the Sudetes was isolated in one JGSM and two GSB exposures, whereas the Late Devonian–Early Carboniferous component (A2) was found in two exposures from the GSB. The corresponding remanent components were already revealed in palaeontologically dated sediments from other West Sudetic units. In the GSB, it was probably acquired during its unroofing dated isotopically for ca. 370–360 Ma. The newly determined group of Palaeozoic directions (A3) was found in three localities from JGSM and in two from GSB is interpreted as the oldest overprint. In JGSM, it was acquired probably shortly after the first oceanic serpentinization phase dated isotopically for ca. 400 Ma. Its acquisition in GSB corresponds to the time of emplacement of ultrabasic xenoliths dated isotopically at ca. 390 Ma. So we suppose that the mean A3 calculated for five exposures corresponds to the 380–400 Ma time span and that at that period both massifs formed one microplate. Mean inclination of A3 places this microplate at 380–400 Ma at the palaeolatitude of 23°S, whereas the West Sudetes were situated during the Early Devonian at 16°S. We suggest that during the Early Devonian the microplate comprising GSB and JGSM massifs was situated to the south from the West Sudetes and accreted them during Middle–Late Devonian.
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 ((87Sr/86Sr)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 ((87Sr/86Sr)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 (δ18O value = 5.2‰) and alkali feldspar (δ18O value = 5.7‰), from alkali clinopyroxenite and foid syenite, respectively, are consistent with mantle-derived magmas. Isotopic compositions of carbonatites and breccias (carbonate δ18O = 8.7‰ to 10.7‰; δ13C = -4.8‰ to −0.4‰) span from values of primary carbonatites to carbonatites affected by a fractionation or sedimentary contamination. The highest values (δ18O = 10.7‰; δ13C = -0.4‰) were reported for breccia cut by numerous veins confirming post-magmatic hydrothermal alteration. The lowest carbonate δ18O (9.3‰ to 10.7‰) and δ13C (−5.0‰ to −3.8‰) values are reported for veins in alkali clinopyroxenites, whereas the highest δ18O (11.2‰) and δ13C (−1.2‰ to −1.1‰) 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 bastnäsite in carbonate veins is similar as in Mo deposits associated with carbonatites, implying the mantle source of Mo and Re.
Abstract Scandian actinolite evolving to scandio-winchite (up to 5.45 wt% Sc2O3) has been found in chlorite-dominant xenoliths incorporated into marginal portion of a granitic pegmatite. The pegmatite intruded a blackwall schist zone developed around rodingite-type rocks exposed in a serpentinite quarry at Jordanów Śląski near Sobótka, ~30 km south of Wrocław, Lower Silesia, Poland. The amphiboles form irregular overgrowths around cascandite and represent a complex solid-solution series among actinolite and scandio-winchite end-members, with a trace contribution of “scandio-magnesio-hornblende.” Structural studies of a scandian actinolite crystal with composition A[☐0.995(2)K0.005(2)]Σ1B[Na0.24(5)Ca1.73(4)]Σ1.98(1)C[Mg3.74(7)Fe0.90(3)2+Mn0.04(1)Sc0.26(3)Al0.05(1)]Σ4.99(1)T[Si7.98(2)Al0.02(2)]Σ8.00O22(OH)2 revealed monoclinic C2/m structure with unit-cell parameters a = 9.8517(3), b = 18.0881(6), c = 5.28501(18) Å, β = 104.809(4)°, in which scandium is located solely at the CM2 site. Scandian amphiboles are uncommon in geological environments, and invite comments on the origin of the observed Sc enrichment in the amphibole structure. Textural appearance of the chlorite-cascandite-amphibole clusters suggests that the formation of the amphiboles is related to the evolution of the country rocks followed by partial alteration of blackwall schist xenoliths by pegmatite-forming melt.
Extensional fractures partly filled with calcite showing the characteristics of flowstone have been observed in the andesite from Jarmuta Mt. The isotopic composition of this calcite indicates low-temperature crystallization conditions and its vadose origin. U-Th dating of the flowstone-like calcite indicates ages of ~2.5-6.5 ka. The calcite grew on a rough and fresh andesite surface, and hence its age may correspond to the age of the extensional fractures. Rhythmically distributed intergrowths of clay minerals present in the calcite may reflect annual climatic oscillations and show that the calcite grew for at least 500 years. The calcite filling the extensional fractures, like the calcite cementing the loosened cataclastic zones cutting the andesite, does not show any features indicating younger deformations. The origin and geometric features of the fractures show that they could have formed in response to increased strike-slip activity within the deep fault zone known as the Dunajec Fault, which may coincide with the fracture zone between the Upper Silesian and MaΠopolska blocks.
Ishikawaite and samarskite-(Y) are indicators of an NYF signature in the mildly to moderately fractionated parts of the hybrid NYF + LCT Julianna pegmatitic system at Pilawa Gorna, the Gory Sowie Block, SW Poland. The minerals were metasomatically altered by a Ca-bearing and Ta-enriched highly fluxed residual silicate melt. The intensity of the metasomatism and the chemical composition of its products strongly depended on the efficiency of the transport of ions to and from the replacement front. Restricted access of the fluid promoted the formation of calciosamarskite and oxycalciopyrochlore. Where the fluid could migrate more easily, with decreasing pH and temperature the alteration products became deficient in A -site cations (mainly Ca 2+ and Mn 2+ ). Consequently, earlier-crystallized pyrochlores transformed to zero-valent-dominant pyrochlores and microlites enriched in U+Th, Y+REE, or Ca. Low-temperature hydrothermal fluids were responsible for the final enrichment in Pb and Bi.
Abstract Our study of boreholes, seismic survey and magnetic data from the region between the Baltic Basin and the Lublin Basin indicates the existence of numerous buried intrusions and effusive complexes, most of them unnoticed so far, together with a few igneous massifs. They are of alkaline character and developed in a time span of c. 348 to 338 Ma. Deep seismic data reveal the presence of large sills (up to 100 km long) within the crystalline basement and the overlying sedimentary cover, at depths of 7–14 km and 5.5–6.5 km, respectively. All these igneous rocks occur in the coherent region and constitute a hitherto unrecognized Lublin–Baltic Mississippian Igneous Province (>120,000 km 2 ). Its denudation is evidenced by the Mississippian volcaniclastic formations of high thickness, developed in the adjacent basins. Igneous activity was triggered by thermal anomaly and/or mantle decompression caused by stress field reorganization, induced by the Variscan collision.
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