Metamorphic manganese mineralisation recently studied at the Smolník - Malá Hekerová deposit is situated within the Early Paleozoic metamorphic volcano-sedimentary sequences of the Bystrý potok Formation (Gelnica Group, Gemericum), Spišsko-gemerské rudohorie Mountains, Slovakia. The manganese mineralisation is associated with metacarbonate bodies, within which Mn-rich calcite, spessartine, titanite, stilpnomelane, fluorapatite and pyrite have been identified. Stilpnomelane is enriched in Mn (up to 2.32 apfu) and Mg (up to 1.68 apfu), while being depleted in Ca, K, Ba and Na. It is considered a retrograde phase formed by the partial dissolution of spessartine. The carbonate-silicate bodies hosting the manganese mineralisation consist of rhodochrosite, kutnohorite, calcite, rhodonite group minerals, spessartine, tephroite, pyrosmalite-(Mn), magnetite, pyrophanite, clino-suenoite, clino-ferro-suenoite, actinolite, clinochlore, chamosite, caryopilite, greenalite, quartz, alabandite, pyrite, pyrrhotite, galena, sphalerite and chalcopyrite. This manganese assemblage is the result of multistage metamorphism during the Variscan and Alpine tectono-metamorphic evolution, which led to distinct mineral associations influenced by the release or incorporation of Fe-rich fluids, silicate alterations and recrystallisation. The multi-stage development is most evident in spessartine crystals, which exhibit chemically strongly distinguishable zones. The presence of significantly Fe-rich tephroite (with up to 31 mol

The ophiolitic blocks in the Cretaceous melanges of the Central Dinaridic Ozren and Borja-Mahnjaca massifs revealed two different evolutionary periods of the Neotethys Ocean: (1) A pre-subduction Middle Triassic to Early Jurassic spreading, and (2) Late Early Jurassic (Toarcian) intra-oceanic subduction and the formation of late Early to Middle Jurassic supra-subduction ophiolitic complex. The goal of this paper is to report the rebuilding of the upper oceanic plate mid-ocean ridge (MOR) abyssal to supra-subduction zone (SSZ) ophiolites. This process is indicated by an increase of Cr# in spinel (Spl) from 0.1 to 0.6, exceptionally to 0.75 in peridotite, the Mg# decrease in orthopyroxene1 (Opx1) from 89-91.5 in abyssal to 86-88 in SSZ types of peridotites, as well as with overall Al and Ti decrease in pyroxene1. However, refertilization was rarely detected in newly formed Cpx, Opx, and Spl (2, 3) generations. A relatively thin, amphibole (Amp)-rich gabbro-dolerite layer of this Jurassic Ozren-Borja-Mahnjaca ophiolitic complex may have formed in a nascent fore-arc, slow-spreading ridge. Remnants of Middle Triassic oceanic crust was dated at 242 f 1 Ma from a relic zircon population in a trondhjemite (remelted plagiogranitic) dyke of the sole eclogite by LA-ICP-MS U-Pb method, whereas its main zircon population of 176 f 2 Ma constrains the metamorphic-anatectic recrystallization age of the dyke in eclogite. Another trondhjemitic dyke gave a magmatic crystallization zircon age of 216 f 6 Ma with rare inherited Middle Triassic (240-230 Ma) zircon. The clinopyroxene (Cpx)-garnet (Grt)-rutile (Rt) eclogites indicate the intra-oceanic subduction of the Triassic oceanic crust to about 50 km, which was estimated from Perple_X modelling of 1.5-1.6 GPa and 860-870 degrees C. However, a sole skarn achieved 950 degrees C at 0.5 GPa. Metamorphic zircon of a sole eclogite yielded 173 f 2 Ma (D1 subduction event at 180-175 Ma). Partial melting of the subducted slab and the mantle wedge initiated the transition of MOR to SSZ type ophiolites. The late Early Jurassic lower oceanic crust was dated on a gabbro (178 f 1 Ma, zircon) and plagiogranite (177 f 1 Ma, zircon). The Spl lherzolite, harzburgite, and dunite are crosscut by early Middle Jurassic Cpx-plagioclase (Pl) and Amp-Cpx-Pl gabbro, gabbro-pegmatite, leuco-gabbro (174 f 1 Ma, zircon), and dolerite (174 f 5 Ma, apatite) dykes, all suggesting an advanced evolutional stage and a shallower level of ophiolites due to extension and the deeper mantle melting in the SSZ setting. Inferred slab roll-back enhanced the sole exhumation (D2) between 175-171 Ma followed by obduction of the upper plate, hot mantle rocks over the exhuming sole (the zircon age of 171 f 0.5 Ma at D3 171-168 Ma from the sole Grt-pargasite-ilmenite skarn). The outboard-directed compression led to the formation of the rear fore-arc basin upper oceanic crust basalt-radiolarite section ( 170-164 Ma) sited on the upper plate lower oceanic crust. Rutile and apatite from an eclogite gave exhumation (cooling) ages of 164 f 3 Ma and 167 f 8 Ma, respectively (D4 at 168-160 Ma). An accretionary wedge ophiolitic breccia, with fragments of the late Early to Middle Jurassic oceanic crust and Triassic and Middle Jurassic radiolarites, indicates the closing of the Middle Jurassic Neotethys after-164 Ma.

The Ozren and Borja-Mahnjača ophiolite complexes in Bosnia and Herzegovina are part of the Dinaridic Triassic-Jurassic ophiolite belt (Putiš et al., 2022; Minerals). Triassic oceanic crust was dated at 242±1 Ma from a relic zircon population in a plagiogranitic layer of partially melted eclogitic sole by LA-ICP-MS U-Pb method, while the main zircon population of 176±1 Ma dates the crystallization of this layer from a metamorphic-anatectic melt. The host sole (Cpx-Grt-Rt) eclogite yielded metamorphic, most likely exhumation zircon age of 168±5 Ma, while rutile gave an age of 165±3 Ma. Jurassic lower oceanic crust was dated from an isotropic gabbro (178±1 Ma, zircon) and plagiogranite (177±1 Ma, zircon). The mantle spinel lherzolites, harzburgites, and dunites are crosscut by Cpx-Pl and Amp-Pl gabbroic, gabbro-pegmatitic, leuco-gabbroic (174±1 Ma, zircon), and doleritic (174±5 Ma, apatite) dykes, all suggesting an advanced evolutional stage and a shallower level of ophiolites due to extension and the deeper mantle melting. The upper oceanic crust pillow basalts are alternating with Bajocian to Callovian radiolarites (~171-162 Ma; Ustalić, Soták et al., 2023; Newsletter of the Slovak Geological Society). The dated N-MORB type sole eclogites-amphibolites indicate the intra-oceanic subduction of the Triassic gabbroic oceanic crust to about 55-60 km that was estimated from Perple_X modelling of 1.9-2.1 GPa and 780°C. Partial melting of subducted slab and a mantle wedge initiated the formation of Jurassic supra-subduction ophiolitic complex detected at ~178-162 Ma. Inferred slab roll-back enhanced the sole extension exhumation between ~170-160 Ma that was coeval with the formation of the upper oceanic crust basalt-radiolarite section. The mineral chemistry-based discrimination diagrams of ultramafic rocks constrain an evolutional trend from MORB to supra-subduction types of ophiolites. An increased depletion of ultramafic rocks is indicated by an increase of Cr# in spinel from ~30 to 60, exceptionally to 75, suggesting transitional abyssal to supra-subduction peridotites and dunites. Relatively thin, often hydrated (Amp-rich) gabbro-dolerite layer of this ophiolite complex may have formed in a fore-arc/back-arc slow-spreading ridge. Ophiolitic breccia, with fragments of the Jurassic oceanic crust and rare Triassic radiolarites, indicates the closure of the Jurassic Neotethys from approximately 160 Ma. Funding from The Slovak research and development agency projects (APVV-19-0065, APVV-20-0079, APVV-22-0092), VEGA agency (1/0028/24, 2/0012/24), and the RVO67985831 program is acknowledged.

The Cucma - Cierna ba & ncaron;a manganese deposit (Slovakia, Western Carpathians) hosts barium-rich mineralisation within the Early Paleozoic metacarbonate lenses associated with graphite-, quartz-muscovite phyllites and metalydites. The main metacarbonate mineral is represented by calcite containing up to 94.2 mol. % CaCO3, with minor amounts of Mn, Fe and Mg constituents. The Ba-mineralisation consists of silicates such as cymrite, celsian, Ba-rich muscovite and baryte along with clinochlore, quartz, spessartine and accessory fluorapatite and rutile. Cymrite forms prismatic to tabular aggregates, commonly associated with celsian and Ba-rich muscovite, it displays a stable chemical composition close to the theoretical end-member formula. Celsian (89.0-97.3 mol. % Cls) with minor Na, K, Ca, and Sr contents typically occurs as anhedral grains and is overgrown by cymrite, indicating a possible hydration transformation. Ba-rich muscovite shows complex chemical zoning, suggesting variable Ba incorporation through multiple substitutions predominantly in Ba-enriched zones (up to 0.32 apfu Ba). Clinochlore lacks any Ba and is interpreted as a retrograde phase. Textural, chemical and structural evidence studied by optical microscopy, electron microprobe analyses (EPMA) and Raman spectroscopy indicates a multi-stage development involving baryte or barium enrichment during sedimentation influenced by submarine basic volcanism, subsequently followed by Variscan and Alpine metamorphic events. Metamorphic recrystallisation mobilised Ba, leading to the formation of Ba-rich silicates. The Ba-rich mineral assemblage and associated textures reflect the complex metamorphic evolution of the deposit and highlight cymrite and celsian as a key indicator of low-grade metamorphism in the studied Ba-rich environment. The presence of spessartine (up to 60.0 mol. % Sps) and other accessory phases further illustrates a close relation with associated manganese mineralisation.

The Sieggraben Complex (SC) in Eastern Austria provides comprehensive information on the pre-Permian, Permian, and Alpine (Cretaceous) evolutional stages of the crustal and mantle sections included into the Austroalpine basement HP/UHP belt. The SC in the Sieggraben-Schwarzenbach area consists of three, top-to-bottom tectono-stratigraphic units: (1) the Paragneiss unit, (2) the Marble-Eclogite unit, which contains MORB and OIB types of mafic rocks, and (3) the Micaschist-Calcschist unit. The N-MORB type mafic rocks yield a U-Pb age of 369.7 +/- 2.0 Ma, have epsilon Nd(370) = +8.5 to +7.4 and TDM(2st) of 0.42-0.50 Ga, while the E-MORB types (U-Pb ages around 400 Ma) show epsilon Nd(400) = +9.4 to +5.6 and TDM(2st) of 0.37-0.67 Ga, both indicating rather juvenile mantle sources during the formation of the inferred oceanic Devonian basin. The rocks of these units revealed Cambrian, Proterozoic, and Archean zircon sources. The ages of 285.8 +/- 9.2 and 265.7 +/- 2.1 Ma from eclogite and amphibolite, respectively, and 265.5 +/- 1.4 Ma from paragneiss indicate an important Permian metamorphic overprint. Permian granitic dykes dated from 265 to 260 Ma, exceptionally at 273 and 253 Ma, crosscut the lithological units. A clinopyroxenite dyke, which crosscuts harzburgite of the underlying mantle fragment, yielded a magmatic age of 253.3 +/- 2.9 Ma. Overall, these ages suggest a strong Permian extension, overheating, and melting of the crustal and mantle rocks. The eclogite ages from 100 Ma, but mainly between 92 and 90 Ma, constrain the Late Cretaceous metamorphic event terminated by an 88.4 +/- 0.8 Ma pegmatite intrusion in the Paragneiss unit. The Permian and Cretaceous metamorphic events often caused resetting of the relatively older zircon ages, together with a decrease of zircon epsilon Hf(t) values, and an increase of whole-rock 87Sr/86Sr values. A Carboniferous metamorphic age of 340 Ma was rarely detected. The SC finally represents a part of an early Late Cretaceous intra-continental subduction zone, which formed within a strongly-thinned crystalline basement due to the Devonian and Permian extensions. A similar Cretaceous suture zone with HP amphibolite, dated at 130-100 Ma by white mica Ar-Ar ages (100-90 Ma exhumation), has been described around the Luben & iacute;k line between the Gemeric and Veporic tectonic units of the Inner Western Carpathians in the framework of the Cenozoic AL-CA-PA (Alpine-Carpathian-Pannonian) microplate.

Ophiolitic m & eacute;langes of the Ozren and Borja-Mahnja & ccaron;a massifs comprise Middle Triassic, Lower Jurassic, and Middle Jurassic radiolarites. The Middle Triassic radiolarites from clastic components in the m & eacute;lange of the Ozren ophiolite complex (OOC) predominantly contain the species Annulotriassocampe and Triassocampe species, together with marker species of the Ladinocampe multiperforata Zone, belonging to the Illyrian. These Middle Triassic radiolarites are remnants of the Maliac Ocean, which opened during the Late Anisian. The inferred continuation of the Middle Triassic radiolarian sedimentation to the Early Jurassic is recorded by radiolarites from block-in-matrix in the m & eacute;lange of the Borja-Mahnja & ccaron;a ophiolite complex (BMOC). Their Sinemurian-Pliensbachian age is indicated by species of the genera Canoptum, Katroma, Droltus, Lantus, Gorgasium, Charlottea, Bipetis, Paleosaturnalis and Paroanella. Such Lower Jurassic radiolarites were so far unknown from the Dinaric ophiolite complexes. The Middle Jurassic radiolarites cover the pillow basalts of the OOC. Their microfauna indicates the Bathonian-early Callovian age based on the LADs of Mizukidella kamoensis and Hemicyrtocapsa carpathica and FADs of Transhuum brevicostatum, Cinguloturris cf. carpathica, Loopus venustus and Protunuma turbo within the UAZ 6-7 Zone. The Middle Jurassic radiolarites are also interbedded in the pillow lavas of the BMOC. In addition to common species of the UAZ 6-7 Zone (e.g., Transhuum maxwelli, Eucyrtidiellum unumaense, Unuma gordus), they also contain the species Takemuraella veghae and Eoxitus cf. baloghi, which are limited to the Bathonian. Considering the radiolarites from the pillow basalts, the OOC and BMOC are interpreted as the m & eacute;langes with the reworked clasts of the Middle Triassic to Lower Jurassic radiolarites, but also with the Middle Jurassic radiolarites. The Middle Triassic radiolarites of the OOC and the Lower Jurassic radiolarites of the BMOC represent rare remnants after the closure of the Middle Triassic to Lower Jurassic Maliac Ocean of the Neotethys. The newly-formed Neotethyan oceanic crust was terminated by the Middle Jurassic radiolarian deposition in an inferred fore-arc/back-arc basin until the Bathonian to early Callovian.

The Ozren ophiolite complex (OOC) of the Dinaridic Ophiolite Belt is one of the six ophiolite complexes in Bosnia and Herzegovina. This paper deals with the mineral chemistry of amphiboles determined by electron probe micro-analysis and micro-Raman spectroscopy. The detected amphibole generations and types in mafic, ultramafic, and metamorphic rocks suggest a polystage evolution and are therefore useful petrogenetic indicators of the investigated OOC. Most gabbroic rocks and dolerites contain primary magmatic amphibole1 (magnesio-hornblende to pargasite, occasionally hastingsite) and prismatic to needle-like aggregates of late magmatic amphibole2 (magnesio-hornblende), while plagiogranite contains ferri-winchite and ferro-ferri-winchite as primary magmatic amphibole. Post-magmatic amphiboles were detected in dolerites, troctolites, and lesser in peridotites. The Na-(Ti)-rich amphibole3 (ferri-winchite and ferro-ferri-winchite to katophorite and ferri-katophorite) with amphibole4 (grunerite) rim formed along the grain boundaries of clinopyroxene, amphibole1, and plagioclase in dolerites. A part of these amphiboles grows into amphibole1, 2. Kaersutite to ferri-kaersutite, associated with phlogopite, occur in troctolites and dunites, while Mhbl was detected in harzburgite. The ultramafic rocks (lherzolites, harzburgites, and dunites) and the gabbroic layer are crosscut by clinopyroxene–plagioclase gabbroic and clinopyroxene–plagioclase–amphibole gabbro–dolerite dykes, suggesting ‘dry’ and ‘hydrated’ percolating melts generated in inferred subridge and supra-subduction settings, respectively. The amphibole3 and 4 in gabbros and dolerites and similar amphibole types in ultramafic rocks could be related to inferred arc-type basaltic and plagiogranitic percolating melts and fluids. Low-Al amphibole5 (tremolite and actinolite) and associated chlorite, albite, and clinozoisite represent the ocean-floor alterations in mafic rocks. Amphibole6 (magnesio-hornblende to pargasite) was identified in metamorphic sole amphibolites. Micro-Raman spectroscopy provided typical Raman spectra for the studied amphiboles, highlighting distinct features such as bands related to CMg content, CFe3+ presence, TO4 ring-breathing mode, TiO6 stretching mode, presence > 0.3 apfu of CTi, and TO4 stretching indicating CFe2+ in the structure. Applied amphibole geothermobarometry revealed the formation P–T conditions of amphibole (Amp)1 (avg. 863 °C at 0.23 GPa), Amp2 (avg. 747 °C at 0.17 GPa), Amp in the mantle rocks (avg. 853 °C at 0.64 GPa), Amp5 (avg. 349 °C at 0.03 GPa), and Amp6 (avg. 694 °C at 0.46 GPa).

The Ozren ophiolite complex (OOC) is the second largest ophiolite complex in Bosnia and Herzegovina, and it is a part of the huge Dinaride ophiolite belt [1 and reference therein]. This contribution comprises mineralogical-petrographical descriptions of representative rocks of the OOC which were determined from polished sections by polarized light microscopy and introductory EPMA. The investigated harzburgites are composed of Ol (55%), Opx porphyroclasts with Cpx exsolution lamellae (35%), Cpx with Opx exsolution lamellae (5%) the latter following Ol-Opx boundaries or ingrowing Opx and Ol matrix. Spinel occurs in the form of anhedral grains. Lherzolites contain Ol (55%), Opx (25%) and Cpx (15%). Anhedral Opx porphyroclasts have Cpx exsolution lamellae. Similarly, porphyroclastic Cpx contains Opx exsolution lamellae. Late magmatic Cpx and Opx aggregates are ingrowing the Ol matrix and these are also surrounding deformed Opx porphyroclasts. Spinel is immersed in the Ol matrix. Dunites are rare. A remnant of the gabbroic layer is inferred only from a borehole core. This gabbro has ophitic texture and contains primary magmatic porphyric Pl, Cpx and green Amp1. Pyroxene and Amp1 are partially replaced by Amp2 and Chl. Plagioclase is weakly altered. Moreover, we found cross-cutting dykes of gabbros (micro-gabbros, called dolerites, to gabbro-pegmatites, and dunite-associated troctolite) in peridotite. These dykes have randomly oriented minerals, only locally showing mylonitization signatures. Most dykes have a discordant relationship to the peridotite structures. Dolerites and basalts also occur in the form of relatively thicker lens-like bodies in serpentinites. A basaltic dyke cross-cuts layered gabbro (in borehole). Most dolerites are composed of Cpx, Amp and Pl but we also found an exceptional Ol-dolerite dyke cross-cutting peridotite. It has well preserved magmatic ophitic texture composed of Ol, Opx, Cpx, Amp, Pl, Ilm and Ap. Pyroxenes and amphiboles are weakly chloritized and Ol is serpentinized. Dolerites and basalts have an ophitic texture, defined by fine-grained prismatic Pl, Px and Amp. Secondary Amp2 and Chl follow the grain boundaries of magmatic minerals. Ophiolitic breccias cover some peridotite parts. These breccias contain 1cm – 10m fragments of all lithological sequences of the OOC including reddish radiolarite sediments. Gabbros from ophiolitic breccia have coarse grained Pl and Px. Exsolution lamellae in Px and kink-banding are characteristic features from subsolidus magmatic conditions. A rare plagiogranite intrusion in peridotite is composed of Qz, Pl and needle-like Amp aggregates after Bt. Such an association of ultrabasic and basic rocks may indicate percolating gabbroic magmas through the peridotites. Amphibolites were found only at one locality so far and these are composed of oriented Amp and Pl aggregates in the metamorphic texture, most likely indicating metamorphic sole of an ophiolitic thrust sheet. These preliminary results shed light on the lithology and petrography of the OOC and have arisen problems for further research. References: [1] Babajić E. (2019) Krivaja-Konjuh ophiolite complex – petrology, geochemistry and geotectonics of mafic sequences. (Monograph), MIT-ALEX, Tuzla (Bosnia and Herzegovina) Acknowledgement: APVV Agency Project No. APVV-19-0065 (M.P.) is acknowledged.

The Dinaride Ophiolite Belt formed from the Jurassic part of the Neotethys. The investigated Ozren ophiolite complex in Bosnia and Herzegovina consists of peridotites, plagioclase peridotites, plagiogranites, troctolites and other gabbroic rocks, and fewer basalts. Lherzolites and harzburgites contain corroded ortho- and clinopyroxene1 porphyroclasts enclosed in the olivine matrix. The boundaries between olivine aggregates and pyroxene1 and spinel1 are infilled by medium-grained undeformed aggregates of clinopyroxene2, less orthopyroxene2, spinel2, and often clinopyroxene3-spinel3 symplectites. These textures indicate the final crystallization of peridotite in subsolidus conditions. Partial dissolution of deformed pyroxene1 porphyroclasts and coarse-grained spinel1 most likely occurred due to their reaction with the rest melt present in the grain boundaries. The Al decrease from pyroxene1 to pyroxene2 and 3, or the Cr decrease and Al increase from spinel1 to spinel2 and 3 is characteristic. Peridotites are associated with inferred remnants of a gabbro-dolerite layer, whereas basalts and radiolarites occur as rare dm-size fragments in an ophiolitic breccia. Troctolites display interstitial crystallization of plagioclase, clinopyroxene, less Na-Ti-rich amphiboles, and phlogopite in the olivine-spinel matrix, indicating the replacive character of impregnating melt within the dunite layers. Clinopyroxene-plagioclase-ilmenite-±amphibole gabbroic and fewer basaltic dykes in peridotites formed due to subridge extension, mantle thinning, and the deeper mantle melting. Iron-enriched olivines occur in the peridotite-dyke interfaces and troctolites. Hydrated ultramafics and mafics contain amphiboles, biotite, phlogopite, clinozoisite, epidote, and chlorite aggregates. Estimated magmatic to subsolidus T from peridotite two-pyroxene thermometry are 1000–850 °C, for the spinel facies. Ca-in-orthopyroxene1 thermometry provided T of 1028–1068 °C, and Ca-in-orthopyroxene2 thermometry gave 909–961 °C at estimated P of 1.1–0.9 GPa. However, the gabbroic dyke magmatic crystallization T was constrained to 1200–1100 °C at P of 0.45–0.15 GPa by single clinopyroxene thermobarometry. The obtained P–T conditions constrained the deeper mantle environment for the formation of peridotites than troctolites and crosscutting dykes. The ophiolitic thrust-sheet hanging wall conditions in an obduction-related accretionary wedge were estimated from amphibolites at 620 °C and 0.85 GPa by Ti-in-amphibole thermometry and amphibole-plagioclase thermobarometry. 300 °C and 0.5 GPa were determined from an exhumation shear zone using a combination of chlorite thermometry and Si-in-phengite barometry.

Basaltic rocks from ophiolitic mélanges provide information on geodynamic setting, origin, and later tectonometamorphic conditions. This paper resolves the P–T conditions and timing of high-pressure metamorphism in an accretionary wedge that formed during the Late Jurassic closure of the Neotethyan Meliata Basin. Blueschist-facies metabasites of the Meliatic Bôrka Nappe and the Albian conglomerate pebbles of the Fatric Klape Nappe contain rare assemblages of garnet in association with glaucophane, phengite, rutile, and epidote (±albite). Here, we compare a Lu–Hf garnet age from the Meliatic Bôrka Nappe in the southern margin of the Inner Western Carpathians (IWC) with a garnet age from inferred Meliatic blueschists of the Klape Nappe overlying the IWC northern margin. The Hačava type locality of the Bôrka Nappe hosts calc-alkaline type metabasite (∼VAB-C; εNd(245) = +0.9) embedded within Middle to Upper Triassic marbles of the Neotethyan Meliata Basin northern continental margin. The investigated Klape Nappe island arc tholeiite (∼VAB-T; εNd(240) = +5.9) blueschist pebble, and associated deepwater metasedimentary rock pebbles were found in a conglomerate layer of unmetamorphosed Albian flysch. The garnet ages of 153.95±0.69 Ma and 152.1±1.5 Ma correspond to closure of the Meliata Basin during southward intraoceanic and continental margin subduction. This was followed by the exhumation of HP blocks in serpentinite mélange and the formation of an accretionary wedge with included anchimetamorphosed Jurassic flysch. The P–T conditions of the blueschists were constrained by Perple_X modelling to be 520°C and 1.55 GPa for the Bôrka Nappe, and 490–510°C and 1.68–1.72 GPa for a pebble from the Klape Nappe conglomerate. The similarity of garnet dates and metamorphic conditions between the two samples suggest that the blueschists formed during the Late Jurassic Meliatic subduction. The north-vergent Meliatic nappes are the inferred source of the Albian flysch conglomerates deposited in the foreland Fatric Basin. This material was subsequently transported by the Fatric Klape Nappe to the IWC orogenic front during the Turonian, following the closure of the Fatric Basin.

Studied calcareous phyllites represent a part of Carboniferous Črmeľ Formation of the Northern Gemericum Unit (Western Carpathians, Slovak Republic). The mineral association of calcareous phyllites is composed of quartz, calcite, muscovite, Mg-Fe chlorites, albite and accessory minerals (fluorapatite, titanite, zircon and tourmalines). Chemical composition of analyzed muscovites has higher contents of Si (3.38 - 3.40 apfu) with K (up to 0.94 apfu), Fe2+ (up to 0.18 apfu) and Mg (up to 0.33 apfu). Chlorites contain Mg in range 2.12 - 2.36 apfu and Fe2+ in range 2.12 - 2.36 apfu with Fe/(Fe+Mg) ratio between 0.49 and 0.54. Chemical composition of albites is Ab97.9-99.7 An1.9Or0.5. Content of F- (up to 0.07 apfu) and OH- (up to 0.07 apfu) in titanite is slightly increased with lower amount Ti (0.89 - 0.92 apfu). In titanites not very significant (Al, Fe3+) + (OH, F) ↔ Ti + O substitution was also identified. Zircon consists of Si (up to 1.04 apfu), Zr (up to 0.96 apfu) and very low content of Hf (up to 0.02 apfu). Two types of tourmalines in calcareous phyllites are also present. Zonal tourmalines with central parts composed of schorl (1.95 - 2.47 apfu Fe; 0.93 - 0.97 apfu Mg; 0.45 apfu Na) and peripheral parts composed of dravite (1.09 - 1.19 apfu Fe; 1.66 - 1.93 apfu Mg; Na up to 0.79 apfu) and indistinctly zoned to non-zoned tourmalines were identified as magnesio-foitite (1.01 - 1.34 apfu Fe; 1.23 - 1.70 apfu Mg; 0.52 - 0.67 pfu vacancy). Studies of calcareous phyllites indicated metamorphic pressure-temperature conditions of 8 - 9 kbar at 330 - 340 °C using chlorite geothermometer and phengite geobarometer.

Investigated metacarbonates are located in the Early Paleozoic rocks of Southern Gemericum unit, Slovakia. Metacarbonates are part of Vlachovo Formation (Tichá Voda, Stará Voda) and Bystrý potok Formation (Betliar, Čučma, Malá Hekerová, Smolník - Mária Terézia, Holec). Detailed studies indicated metamorphic pressure-temperature (P-T) conditions of 3 - 7 kbar at 330 - 370 °C for the Gelnica Group. The calculated P-T conditions were verified using chlorite geothermometer and phengite geobarometer. Mineral association of metacarbonates consists of Si rich (3.10 - 3.35 apfu) phengitic micas, Fe-Mg chlorites (clinochlore and chamosite), quartz, K-feldspars and accessory fluorapatite. Micas and Mg-Fe chlorites originated from metamorphic recrystallization of clay material with incorporations of basic pyroclastic material during the regional metamorphosis of pelitic protolith, which sedimented continuously with carbonates. Metacarbonates belong to the upper parts of Gelnica Group, which were metamorphosed under the greenschist facies conditions.

Garnet skarn mineralization was recently studied at the Trohanka locality near Prakovce (Gemeric Unit, Eastern Slovakia). Ca-skarn forms lenticular bodies in green schist environment. It mainly consists of zonal garnets, pyroxenes, amphiboles and magnetite accumulations. Studied garnets are rich in andradite component (up to 89.95 mol. %) with minor grossular component (6.83 - 39.67 mol. %). Strong oscillatory zoning in andradite is caused by substitution of Fe3+ and Al3+. Most pyroxenes are rich in the hedenbergite component. In some cases, euhedral diopside crystals with marginal transition zones (composed of diopside with lower content of Mg2+ and higher content of Fe2+) were found in hedenbergite matrix. Amphiboles are dominantly represented by ferro-actinolite and ferro-hornblende in association with isolated euhedral crystals of ferro-tschermakite and ferro-pargasite. Indistinct chemical zonality of amphibole euhedral crystals is caused by presence of ferro-pargasite in the central parts and ferro-tschermakite in the peripheral parts of crystals.

Analyzed garnets from the Magnet hill area near Tisovec (Slovak Republic) are part of a Ca-skarn mineral association consisting of diopside, clinochlore and calcite. Compositionally they correspond to Ti-rich andradite (Adr50.9-73.7) with minor grossular (Grs3.8-44.5) and schorlomite (Sch0.5-41.5) components. Garnets contain up to 13 wt. % TiO2 and in all of them YFe3+>YTi ratio prevails. Both sector and oscillatory chemical zoning were observed, which is primarily caused by variable distribution of Ti contents within individual garnet crystals. The three principal zones were distinguished in BSE imaging. The brightest are Ti-enriched zones with Ti content ranging from 0.85 to 0.50 apfu. Titanium gradually decreases in transitional zone (0.17 - 0.40 apfu) and reaches the minimum values in the dark zones (0.01 - 0.13 apfu). In the Ti-enriched zones the content of Si4+ and Al3+ is decreased due to substitution of Ti4+ and Fe3+ and assumed hydrogarnet substitution (SiO4)4- ↔ (O4H4)4-.

The composite Albian–Eocene orogenic wedge of the northern part of the Inner Western Carpathians (IWC) comprises the European Variscan basement with the Upper Carboniferous–Triassic cover and the Jurassic to Upper Cretaceous sedimentary successions of a large oceanic–continental Atlantic (Alpine) Tethys basin system. This paper presents an updated evolutionary model for principal structural units of the orogenic wedge (i.e., Fatricum, Tatricum and Infratatricum) based on new and published white mica 40Ar/39Ar geochronology and P–T estimates by Perple_X modeling and geothermobarometry. The north-directed Cretaceous collision led to closure of the Jurassic–Early Cretaceous basins, and incorporation of their sedimentary infill and a thinned basement into the Albian–Cenomanian/Turonian accretionary wedge. During this compressional D1 stage, the subautochthonous Fatric structural units, including the present-day higher Infratatric nappes, achieved the metamorphic conditions of ca. 250–400 °C and 400–700 MPa. The collapse of the Albian–Cenomanian/Turonian wedge and contemporary southward Penninic oceanic subduction enhanced the extensional exhumation of the low-grade metamorphosed structural complexes (D2 stage) and the opening of a fore-arc basin. This basin hemipelagic Coniacian–Campanian Couches-Rouges type marls (C.R.) spread from the northern Tatric edge, throughout the Infratatric Belice Basin, up to the peri-Pieniny Klippen Belt Kysuca Basin, thus tracing the south-Penninic subduction. The ceasing subduction switched to the compressional regime recorded in the trench-like Belice “flysch” trough formation and the lower anchi-metamorphism of the C.R. at ca. 75–65 Ma (D3 stage). The Belice trough closure was followed by the thrusting of the exhumed low-grade metamorphosed higher Infratatric complexes and the anchi-metamorphosed C.R. over the frontal unmetamorphosed to lowest anchi-metamorphosed Upper Campanian–Maastrichtian “flysch” sediments at ca. 65–50 Ma (D4 stage). Phengite from the Infratatric marble sample SRB-1 and meta-marl sample HC-12 produced apparent 40Ar/39Ar step ages clustered around 90 Ma. A mixture interpretation of this age is consistent with the presence of an older metamorphic Ph1 related to the burial (D1) within the Albian–Cenomanian/Turonian accretionary wedge. On the contrary, a younger Ph2 is closely related to the late- to post-Campanian (D3) thrust fault formation over the C.R. Celadonite-enriched muscovite from the subautochthonous Fatric Zobor Nappe meta-quartzite sample ZI-3 yielded a mini-plateau age of 62.21 ± 0.31 Ma which coincides with the closing of the Infratatric foreland Belice “flysch” trough, the accretion of the Infratatricum to the Tatricum, and the formation of the rear subautochthonous Fatricum bivergent structure in the Eocene orogenic wedge.

Crystalline limestones containing fragments of amphibolites from the locality Dobšiná - Kruhová are part of the Klátov complex (Northern Gemericum, Western Carpathians). The colour of studied rocks is light grey with massive texture and granoblastic structure. Inhomogeneous mottled to breccia-like character of a crystalline limestones is caused by the presence of amphiboles in the studied rocks. The identified mineral association of crystalline limestones consists of calcite, amphiboles (pargasite, magnesio-hornblende, actinolite), clinopyroxenes (diopside), albite and titanite. Chemical zonation of amphiboles from the crystalline limestones and fragments of amphibolites have been studied in BSE imaging. Light grey BSE zone is represented by pargasite (with more Fe2+ up to 1.37 apfu and less Mg up to 2.26 apfu) and dark grey BSE zone is represented by magnesio-hornblend and actinolite (less Fe2+ 0.68 apfu in magnesio-hornblende; 0.62 apfu in actinolite and more Mg up to 3.30 apfu in magnesio-hornblende and up to 4.03 apfu in actinolite). Diopside has slightly higher content of Al (up to 0.13 apfu) and low content of Fe2+ (up to 0.17 apfu) with XMg ratio in the range 0.83 - 0.96. Chemical composition of albites is Ab91.12-98.21An1.52-5.12 with ortoclase component in the range 0.22 - 4.49 mol. %. Titanites from the amphibolite fragments and crystalline limestones have identical chemical composition (Ca up do 1.00 apfu, Si up to 0.97 apfu). Lower content of Ti (0.88 - 0.95 apfu) and higher content of F (up to 0.27 wt. %) and H2O (up to 0.38 wt. %) is present. In titanites not very significant (Al, Fe3+) + (OH, F) ↔ Ti + O substitution was also identified. We assume that pargasite and magnesio-hornblende are products of prograde etape of metamorphosis unlike actinolite which is product of retrograde etape of metamorphosis. Diopside was generated by dehydration and decomposition processes of magnesio-hornblende and pargasite in a high-temperature prograde regime of metamorphosis in the conditions of upper amphibolite facies. Calcite is chemically pure, presence of dolomite has not been confirmed.

Atoll garnets in basalt metapyroclastics from the locality Čučma - Vincent (Slovak Republic) consist of relict cores and zonal rings. Research was focused on comparison of chemical changes in these garnet microstructures. Relict cores have composition Sps41.4-45.2Grs40.6-43.0Adr6.4-13.6 Alm1.9-6.1, inner BSE light zone in the rings has composition Grs38.2-44.9Sps39.6-43.7Alm6.3-12.4 Adr6.5-9.6 and outer BSE dark zone in the rings has composition Sps34.3-40.3Grs33.3-38.3Adr8.5-17.3 Alm12.7-17.1. The highest content of Mn2+ in the atoll garnets was observed in the relict cores (1.21 - 1.33 apfu) and subsequent decreasing trend in contents of Mn2+ from the inner parts of the rings (BSE dark zone; 1.16 - 1.29 apfu) to their edge (BSE light zone; 1.02 -1.20 apfu) is present. The opposite trend was observed for Fe2+ content. Inner parts of the garnets are replaced by actinolite and calcite with slightly higher content of Mn (Act up to 0.07 apfu; Cal up to 0.02 apfu). Matrix of basalt metapyroclastics was primarily formed by hedenbergite which was later replaced by actinolite.

Visualization of garnets and their mineral inclusions was performed by X-ray microtomography by reconstructing 3D image from 1800 measured 2D X-ray projections. Visualization procedure of 3D distribution of mineral inclusions was based on the different absorption of X-ray radiation between the host garnet and mineral inclusions. 3D visualization provided a realistic picture of a distribution of the 126 identified mineral inclusions in garnet from rhyolite and rhyodacite Beňatinská voda and 21 inclusions in garnet from Lesné - Potičky (Slovak Republic). Composition of garnet from locality Lesné - Potičky is Alm71.0-73.7Prp8.3-9.0Grs14.7-16.6 and from locality Beňatinská voda is Alm72.1-73.2 Prp5.5-5.9Grs18.3-19.4. Mineral inclusions in garnets from locality Lesné - Potičky are represented by fluorapatite, zircon, ilmenite, annite and magmatic melts preserved in the form of glass inclusions trapped in apatite inclusions. Mineral inclusions in garnets from locality Beňatinská voda are represented by fluorapatite, zircon and plagioclase An78.53-57.12. Chemical composition of zircons and fluorapatites are similar from both localities. Based on the chemical composition, the high-pressure origin of garnets associated with I-type magmas was confirmed.