Formation of a Composite Albian–Eocene Orogenic Wedge in the Inner Western Carpathians: P–T Estimates and 40Ar/39Ar Geochronology from Structural Units

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.


Introduction
Subduction-collision processes and the formation of accretionary wedges [1] are usually related to the closure of oceanic basins. The Inner Western Carpathians (Slovakia, Central Europe) provide an example of a complex accretionary wedge, which in addition to oceanic basins, incorporated a riftogenic continental basin system.
The Inner Western Carpathians (IWC) comprise two principal orogenic wedges: (i) the southern, so-called Meliatic-Gemeric-Veporic wedge of Late Jurassic-Early Cretaceous age, derived from the Neotethys Ocean and its northern passive continental margin, and (ii) the northern, so called Fatric-Tatric-Infratatric wedge derived from the Atlantic Tethys Ocean (Alpine Tethys, sensu [2]) southern (active) continental domain; it formed in two stages during Albian-Cenomanian/Turonian and Eocene times [3,4] and references therein.
A polystage evolution of the northern (Fatric-Tatric-Infratatric, or FTI) wedge is not adequately explained and continues to be a matter of discussion. For example, some authors argued that in the pre-collision stage, a continuous cover succession without any tectono-metamorphic events was formed within the Infratatric Unit (Infratatricum) of the FTI wedge during Triassic to Late Cretaceous times ( [5] and references therein). In contrast, some authors argued that metamorphosed olistolithic to clastogenic material, including the Lower Cretaceous slates found in the Upper Cretaceous "flysch" of the Infratatricum, provide evidence for a tectono-metamorphic event prior to the Late Cretaceous [3,6,7]. This tectono-thermal event was constrained to ca. 100 Ma based on white mica 40 Ar/ 39 Ar geochronology applied to the Infratatricum [3,7].
To address this controversy, we present an updated evolutionary model for the northern FTI wedge. The model is based on the tectono-thermal events recognized in the reappraised basement-cover structural complexes by published and new P-T estimates and white mica 40 Ar/ 39 Ar geochronology from the major shear zones. We focus on the subautochthonous Fatricum (or an inferred tectonically reduced basement-cover structural complexes of the Fatricum) and the Infratatric basement-cover structural complexes which show much more distinct tectono-thermal overprint than the central Tatric sliver.

Review of the Western Carpathians Tectonic Units
The principal tectonic units of the Western Carpathians ( Figure 1) are briefly characterized from north to south as follows: The Pieniny Klippen Belt (PKB) is a Cenozoic structure separating the Outer (OWC) and Inner Western Carpathians (IWC). The OWC are limited by the Neogene Carpathian Foredeep deposits in the North which are overridden by the Cretaceous to Palaeogene flysch rootless nappes of the inner Magura and outer Silesian units. The Stramberk Jurassic-Cretaceous klippen may be a prolongation of the Helveticum, and the Magura Unit is equivalent to the Rhenodanubian Flysch Zone of the northern Penninicum [8].
An intra-continental branch of the Atlantic Tethys (or Alpine Tethys after [2]) called the Fatricum [14] was located between the Tatricum and Veporicum. The Fatric nappes are presumed to have formed from a Jurassic to Lower Cretaceous sedimentary infill of the Fatric (Zliechov) Basin which originated on an extensionally thinned basement (~Variscan crystalline basement with a Permian-Triassic pre-rift cover) in a transitional area of the present-day Tatricum and Veporicum. The Fatric (Zliechov) Basin was closing from the late Albian to Cenomanian at ca.  Ma and the Fatric nappes were thrust onto the Tatricum during the Turonian to Santonian ( [5,8,[13][14][15][16][17] and references therein) and overlain by the Hronic nappes [8]. The Late Cretaceous Čertovica thrust-fault separates the Tatricum and Fatricum (including the so-called north-Veporic area), the structural complexes of which show different grade of the Alpine metamorphic overprint (e.g., [19,20]). The central Tatric sliver consists of the relatively thicker basement rocks with the meso-Variscan granitic plutons intruded in the higher-grade metamorphics, such as gneisses, amphibolites and migmatites [21], and covered by the Triassic platformal and Jurassic-Cretaceous deep-water Šiprúň or shallow-water Tatra successions of the Tatric Basin. The closure of this basin occurred in the Cenomanian to Turonian as documented by the termination of sedimentary successions by pelagic "flysch" sediments (e.g., [8] and references therein).
The Infratatricum developed from the deep-water Middle Jurassic to Lower Cretaceous successions which were deposited on a distant thinned continental margin basement [3,22]. The Infratatric deep-water Orešany Succession appears to have been formed in a transitional area to the south-Penninic oceanic basin. The southward Penninic subduction of Penninic Ocean opened the Infratatric fore-arc Late Cretaceous basin system on the upper plate [3,6].
A wide range of the blastomylonitic white mica 40 Ar/ 39 Ar ages from ca. 100 to 50 Ma have been reported from the northern IWC wedge [3,7,[23][24][25][26][27][28]. The Early Cretaceous zircon fission-track (ZFT) ages of ca. 144-135 Ma and an Eocene age of ca. 45 Ma obtained for basement rocks prove a very low-grade thermal overprinting in the Tatricum during the Early Cretaceous and Eocene extensions [29]. Zircon (U-Th)/He (ZHe) and apatite fission-track (AFT) ages between ca. 50 and 40 Ma are interpreted as erosional and tectonic exhumation of the basement units due to the extensional collapse of the Carpathian orogenic wedge [30].
The IWC southern (Meliatic-Gemeric-Veporic or MGV) wedge formed due to the closure of the Middle Triassic-Late Jurassic Neotethyan oceanic Meliata Basin and southward subduction of its oceanic and continental margin crust at ca. 160-150 Ma [4,23,24,[31][32][33] and references therein. The MGV wedge also comprises a decoupled part of the Gemeric and Veporic thinned continental margin which accreted to the Meliatic subductionrelated accretionary wedge at ca. 140-110 Ma ( [34,35] and references therein). Contemporaneous exhumation and cooling of the overthrusting high-pressure metamorphosed Meliatic fragments is constrained by the zircon (U-Th)/He thermochronology [34] and the monazite in situ EPMA dating in the underlying southern Gemericum [36,37]. The Meliaticum overlies the Gemericum and is overlain by Silicic nappes [8] and references therein.

Allochthonous vs. Subautochthonous Fatricum
The Tatric Unit (Tatricum) appears to have weaker Alpine tectono-metamorphic overprinting than the Veporic Unit (Veporicum). Internally, the marginal Tatric domains show a more distinct tectono-metamorphic overprinting grade than its central, mostly unmetamorphosed sliver. These marginal zones were defined by [22] as individual structural units of the Tatricum, termed Infratatricum and Supratatricum. For example, the north-Tatric low-grade tectono-metamorphosed structural units in the Považský Inovec Mts., underlying the unmetamorphosed central Tatricum were called "Infratatricum".
Similarly, the greenschist facies tectono-metamorphosed basement-cover structural units in the area south of the central Tatricum (i.e., between the Čertovica and Pohorelá lines) in the Tribeč Mts. and the eastern Nízke Tatry Mts. were called "Supratatricum" and were considered the root zone of the Mesozoic Fatric nappes ("Fatricum" after [14]) overriding the Tatricum. However, the compressed basement of the Fatricum root zone south of the Čertovica line is also traditionally termed "Northern Veporicum" in the eastern Nízke Tatry Mts. or "Tatricum" in the Tribeč Mts. Zobor block (e.g., [5,8,18,38]). To remove duplicate terminology of Fatricum/Northern Veporicum/Supratatricum, we choose to use the following principal Late Cretaceous structural units of the IWC with the Variscan basement participation: Infratatricum (N of Hrádok-Zlatníky line), Tatricum (between Hrádok-Zlatníky and Čertovica lines), Fatricum (between Čertovica and Pohorelá lines), Veporicum (between Pohorelá and Lubeník lines), Gemericum (between Lubeník and Rozňava lines) and the Hronicum, Meliaticum and Silicicum as Upper Paleozoic-Mesozoic rootless nappes. The Fatricum [14] has an allochthonous supratatric position presented by the Krížna nappe system, and this was introduced approximately 20 years before the introduction of Supratatricum [22], therefore, we prefer Fatricum to Supratatricum although the latter would be an equivalent term to the Infratatricum from a structural viewpoint.
An important question is-what was the basement of the detached Mesozoic Fatric nappes finally bivergently overriding the Tatricum and Veporicum? Paleogeographically, there was a large domain of the Jurassic-Lower Cretaceous basement extension and the basin formation in the northern part of the IWC which, after the inversion, transformed into the main Late Cretaceous structural units such as the Infratatricum, Tatricum and Fatricum, including the newly defined subautochthonous Fatricum in this paper. We do not overlap a pre-Fatricum with the pre-Tatricum or pre-Veporicum but consider it as an individual paleogeographic domain that developed during the Jurassic-Early Cretaceous intracontinental extension. It is inferred that the central deep-water Middle Jurassic to Lower Cretaceous Fatric Basin Zliechov Succession formed on a strongly thinned pre-rift basin basement, while the laterally shallowing successions formed toward partly thinned continental margins. Thus, the south-Fatric continental margin is represented by the Veľký Bok, Lučatín and Veľké Pole type successions, and the north-Fatric margin by the Vysoká, Manín and Veľký Tribeč type successions of a large at least first-hundred-km wide Fatric Basin [8,13,14,39].
Following the Fatric Basin closure, the thinned basin basement and a part of the sedimentary infill underwent compressional southward underthrusting below the Veporicum in the front of the Neotethyan wedge. The exhumed tectono-metamorphosed basement-cover structural units from this suture zone are termed here the subautochthonous Fatricum to stress their close relationship to allochthonous or detached Fatric Mesozoic cover nappes sensu [14]. This area of the Fatricum is the homeland or the root zone of the Fatric nappes, finally bivergently overriding the Tatricum and Infratatricum, and the Veporicum. The southeast-vergent part of the subautochthonous Fatricum is represented by the Vápenica Nappe [21,40,41] with the Veľký Bok type Permian-Lower Cretaceous cover succession in the eastern Nízke Tatry Mts. (Figures 2 and 3). This nappe with a high-angle discordance is overlying the compressed south-Fatric (called also north-Veporic) structural units, such as the Ľubietová and Krakľová after [42]. The Staré Hory Nappe in the western Nízke Tatry Mts., and the Razdiel (an equivalent of the Vápenica Nappe) and Zobor nappes in the Tribeč Mts. of subautochthonous Fatricum are north-vergently overlying the Tatric sliver, and thus the Čertovica thrust fault is inferred to the north of the Tribeč Mts., although covered by the Cenozoic sediments.
The flat-lying Vápenica Nappe on the compressed WSW-ESE striking and mostly steeply south-dipping structure of the south-Fatric (former north-Veporic) phyllonite zones indicates postponed back-thrusting in relationship to the northward Fatric nappe formation. The Late Cretaceous sinistral transpression zone between the Tatricum and newly defined Veporicum (i.e., former southern Veporicum) or between the Čertovica and Pohorelá thrust faults formed after the expulsion of the Fatric nappes over the Tatricum.
The Vápenica Nappe consists of metamorphosed Veľký Bok type Permian-Lower Cretaceous succession overlying the tectonically reduced and sheared-off 100-300 m thick granitoid basement. Blastomylonitized granodiorites to tonalites and the sedimentary cover show the same low-grade tectono-metamorphic overprinting in the whole area of the eastern Nízke Tatry Mts. and the Upper Hron Valley. The thrust plane of the Vápenica Nappe may be a reactivated originally north-dipping extensional fault of the southern Fatric Basin continental margin. The SE/ESE-vergency of the Vápenica Nappe still under ductile conditions over the south-Fatric Ľubietová and Krakľová nappes is indicated by the WNW-ESE to E striking stretching lineation of granitoid blastomylonites. Similarly, the Krakľová Nappe is back-thrust over the Veporic front in the Kráľova Hoľa Massif also with a southvergent duplex structure [40,41,43,44] and Geological Map 1:50,000, and Figure 2.
A sheet of the blastomylonitized granitoids and the Triassic to Lower Cretaceous metamorphosed cover, exposed at the surface in the Zobor Nappe is terminated by the Skýcov NW-SE striking fault zone in the middle of the mountains. The Razdiel Nappe behind the Skýcov fault zone reveals the core of an open NW merging antiform composed of the phyllonitized micaschists and amphibolites. The limbs of this structure are formed by a blastomylonitized granitoid sheet composed of granodiorites to tonalites on the top, and the porphyric granites to fine-grained granites and leucogranites at the bottom. The SW part of the antiform at the Skýcov fault zone is compressed and the granitoids and the Permian cover rocks are underthrust below the micaschists and amphibolites of the antiform core.  [41]). 1a-Quaternary and Cenozoic deposits; Outer Western Carpathians Flysch Belt (OWC-FB); 1b-Neogene andesites; 2-Choč Nappe (Hronicum); 3-Triassic-Lower Cretaceous Veľké Pole (Veľký Bok type) Succession [45] of the Razdiel Nappe; 4-Permian volcano-sedimentary succession of the Razdiel Nappe; 5-Lower Triassic quartzites of the Zobor Nappe (a part of the Veľký Tribeč Massif Triassic-Lower Cretaceous Succession); Variscan basement of the Razdiel and Zobor nappes: 6-Tonalites to granodiorites; 7-Granites mostly leucocratic; 8-Amphibolites; 9-Micaschists; 6-8-Variscan Upper Unit; 9-Variscan Middle Unit. Structural elements: 10-Thrust plane of the Hronic Choč Nappe; 11-Cretaceous thrust fault of the Razdiel Nappe over the Zobor Nappe in the subautochthonous Fatricum; 12-Detached fragments of the Mesozoic cover; 13-Important thrust planes after subhorizontal nappe thrusting; 14-Faults, strike-slips (a) and geological boundaries (b); 15-Pre-Alpine metamorphic schistosity/foliation (a) or lineation (b), Alpine schistosity (a) or stretching lineation (b).
The sedimentary Permian to Lower Cretaceous metamorphosed cover rocks is systematically on top of the upper granitoid sheet, and this situation indicates partly preserved Variscan basement tectono-stratigraphy in the core of the Razdiel Nappe Alpine structure [22,[46][47][48]. The upper part of the Razdiel Nappe granitoid sheet, composed of the 300-400 thick blastomylonitized granitoids and the Permian-Lower Cretaceous cover of the Veľký Bok type Veľké Pole Succession [45], resembles the structure of the Vápenica Nappe in the eastern Nízke Tatry Mts. (Figure 3).
The NW-ward vergency of the Zobor Nappe was determined from the asymmetry of the S-C structures and NW-SE striking and mostly shallowly SE-dipping stretching lineation of the tonalite blastomylonites in the Nitra and Zlatno areas. The last extensional meso-structures indicate an opposite SE-vergent sliding. The same meso-and micro-structures and shear-sense were observed in the Razdiel Nappe granitoid blastomylonites which occur, for example, in the Chudá Valley and Kamenná Hill areas (see also the Section 4.1.2.).

The Infratatricum
The Selec Block in the Považský Inovec Mts. north of the Hrádok-Zlatníky thrustfault was called "Carpathian Penninic" by [49] because of the Alpine tectono-metamorphic overprinting [50,51] and submerging below the central Považský Inovec Mts. Bojná Block of a typical unmetamorphosed Tatricum. The latter is considered analogous to the Lower Austroalpine Unit of the eastern Alps (e.g., [9,12,13]). The Selec Block structure was redefined by [22] as the Infratatricum, directly underlying the Tatricum ( Figure 5). The general orogenic structure is documented in an interpretative reflection seismic cross-section by Tomek in [3].
The reconstructed deep-water Middle Jurassic to Lower Cretaceous Humienec Succession in the northern part of the Považský Inovec Mts. was considered a representative of the Penninic Ocean distal continental margin [3,6,52]. In contrast, [8,53] and Plašienka [5,54] considered that this succession, including the Upper Cretaceous sediments [55], exposed oceanic Váhicum [9] or the oceanic southern Penninicum pendant. However, the calc-alkaline meta-basalt fragments in the Upper Cretaceous "flysch" were derived from the Permian volcano-sedimentary succession of the higher Infratatric Inovec Nappe, and the inferred oceanic crust was not confirmed [3,6,51,52,56,57]. Because of the absence of Jurassic-Cretaceous ophiolites, we consider that this Jurassic-Lower Cretaceous continental margin Humienec Succession, the remnants of which were discovered in the lower Infratatric Humienec thrust sheet, is either an integrated part of the south-Penninic Realm [3,6] or an unknown basin, probably of the Fatric Realm (this paper, and the reasons see in the Discussion Section 5.2.). In contrast, the higher Infratatric Inovec Nappe and the Tatric Panská Javorina Nappe are considered pendants of the Lower Austroalpine units s.l.
The micaschist-gneiss basement and the cover rocks of the higher Infratatric Inovec Nappe show distinct Alpine tectono-metamorphic overprinting in the higher anchi-metamorphic to lower greenschist facies [3,50,51,56]. These overlie the lower Infratatric Humienec thrust sheet which also incorporates Upper Cretaceous Couches-Rouges-type (C.R.) reddish marlstones and "flysch" pelagites ( Figure 5). The stratigraphic extent of the marls at least up to the Santonian was confirmed by Marginotruncana coronata Bolli foraminifera [6,52]. These sediments contain thin fine-grained detrital layers which are most likely turbiditic in origin. The extent of the C.R. was significant, from the Tatric edge up to the peri-PKB (see also [17,58,59]).
The inferred Penninic subduction (ca. 90-75 Ma) termination and the change from an extension to compression regime is recorded in the lower anchi-metamorphic overprinting of the C.R. during the D3 stage inferred at ca. 75-65 Ma, when the Belice Basin rebuilt to a trench-like "flysch" trough infilled by the Late Campanian(?)-Maastrichtian siliciclastic and calciclastic pelagites. Contemporarily, the C.R. underthrust below the Inovec Nappe. Most of the lower Infratatric frontal Humienec thrust sheet members occur in the "flysch", often in the form of olistoliths and scarp breccias which shaded southwards in the basin [3,6]. In contrast, the "flysch" sources from the higher Infratatric Inovec Nappe were derived from the south, or from the exhumed rear Inovec Nappe as a part of the collapsing Albian-Cenomanian/Turonian wedge front ( Figure 6A,B).  [3,6,50]; higher Mesozoic Krížna and Choč nappes from [60]. TA-Tatricum, IFTA-Infratatricum.
Part of the Infratatric structure is also exposed in the relatively small Hlohovec Block in the southern part of the Považský Inovec Mts. [39,61]. While the Selec Block structural units were described in more detail by [3] and references therein, the structure of the Hlohovec Block ( Figure 7) is less known, and it will therefore be described here in greater detail and include our new field observations.
The HPJ-1 Jašter structural-geological drill-hole at Hlohovec revealed steeper 50-70° direct tectonic contact of the Upper Cretaceous Couches-Rouges-type reddish marls (C.R.) with the deformed granodioritic basement. This situation was interpreted as marls sliding into the adjoining Neogene basin along an extension fault, and contemporary exhumation of the basement granodiorite and the Triassic-Jurassic cover of the Tatricum [62].
Although the large area of the Hlohovec Block is under the Quaternary sediments [60], the deeply eroded valleys and quarries yield sufficient information on the geological structure. The Soroš quarry near Hlohovec township reveals direct tectonic contact or the thrust plane of the Middle Triassic marble sheet over the anchi-metamorphosed C.R. (Figures 7  and 8A). The metamorphosed hemipelagic marly limestone (Lower Cretaceous?) in association with the recrystalized Jurassic sandy crinoidal limestones, Middle Triassic marbles and Lower Triassic meta-arkoses and meta-quartzites complete the cover succession of a small granodiorite massif near Hlohovec. While the Lower Triassic rocks are closely bound to the underlying granodiorite, the Middle Triassic-Lower Cretaceous(?) marble sheet was detached from the basement and thrust over the C.R. as an independent tectonic body. This is assigned here as the higher Infratatric Hlohovec Nappe, with equivalent structural position to the higher Infratatric Inovec Nappe in the northern Selec Block, particularly the Hradisko Hill thrust sheet of this nappe ( Figures 5 and 7).
The laminated grey calcitic and calcitic-dolomitic marbles have metamorphic schistosity covered with clearly visible white mica aggregates. The schistosity planes (S1) are shallowly ESE dipping. The stretching lineation on the S1 planes is WNW-ESE striking and 10-15° ESE dipping. Dark-gray marbles are transformed into yellow white carbonatic schists at the C.R contact (D3 stage). These new dense schistosity planes (S2) contain newly formed very fine-grained white-mica aggregates. The secondary schistosity of the marble mylonites/ultramylonites (S2) is equivalent to the anchi-metamorphic schistosity (S1) of the underlying C.R. The intrafolial folds of the C.R. marls are cosscut with the secondary cleavage S2 which may be related to the later (D4) thrusting of the marly slates over the "flysch" sediments in the foreland.
A younger recrystalized fine-grained white-mica2 aggregates formed in the hanging wall marble ultramylonites of the Triassic-Jurassic-Early Cretaceous(?) marble thrustsheet, most likely during the underthrusting of the footwall C.R. type reddish marls during the D3 compression stage. This may explain the differences in the metamorphic overprinting compared to the C.R. slates with "flysch" sediments after the D4 stage at ca. 65-50 Ma when the whole Infratatric Upper Cretaceous sedimentary succession was included in the IWC Eocene accretionary/orogenic wedge [3]. Although the fold-cleavage structures also occur in the "flysch" sediments, they exhibit negligible metamorphic overprinting at the boundary of the diagenesis and lower anchi-metamorphism (see the Section 4.1.1.).
The advanced D4 stage occurred in the brittle-ductile regime. Kink folds with NE-SW axis and SE-ward vergency occur in the C.R. slates directly below the marble thrustplane in the Soroš quarry. Moreover, the marble thrust sheet hanging wall contains cataclasite and rauhwacke layers which may have formed during overthrusting of the almost unmetamorphosed "flysch" sediments ( Figure 7). Steepened thrust-faults and backthrusts are typical in the NW part of the Selec Block ( Figure 5), thus indicating an important collision-transpression event most likely related to the PKB Cenozoic structure formation. Part of the rugged Albian-Cenomanian/Turonian wedge basement, including the tectonized granodiorites, were tectonically emplaced in the anchi-metamorphosed C.R. sediments forming a mélange. Similarly, the distinctly tectono-metamorphosed marble fragments of the Hlohove Nappe thrust sheet in the form of lensoidal blocks (xm-x10m) were infolded into the soft reddish marly slates and this mélange-like structure is also documented in the Soroš quarry near Hlohovec ( Figure 8B).

Tatricum
The Tatric Basin shallow-(Tatra) and deep-water (Šiprúň) Mesozoic cover successions terminate with the Albian-Cenomanian flyschoid Poruba Formation (e.g., [8,39]). Turonian age of the formation was confirmed only in the Tatra and Veľká Fatra Mts. [64,65]. The youngest Turonian-Santonian age of the Tatric Mesozoic cover was determined in the Hubina Formation which discordantly overlies the Poruba Formation in the Bojná Block of the Považský Inovec Mts. [17]. This formation partly resembles the Infratatric Upper Cretaceous succession of the Selec and Hlohovec blocks in the Považský Inovec Mts.
The phyllonite zone of the Tatricum's western margin in the Lúčanská Malá Fatra Mts. merges SE-wards below the crystalline massif and appears in the Valča and Bystrička valleys tectonic windows [7]. The newly formed white mica yielded 72.4 ± 2.7 Ma 40 Ar/ 39 Ar plateau age [26], and a similar 40 Ar/ 39 Ar step age cluster was obtained by [7]. The newly formed white mica of Ms to Ph composition from the phyllonites and underthrust marble mylonites ( Figure 9) yielded higher anchi-metamorphic to lower greenschist facies temperatures at lower to medium pressures [69] (Table 1).  The most typical are common fold and thrust structures of the basement and the cover rocks in the Tatra and Nízke Tatry Mts. which formed under brittle-ductile conditions. Despite very low-temperature deformation conditions, the Upper Variscan Unit granodiorite kalifeldspar at Velické Pleso Lake in the Tatra Mts. yielded minimum measured 40 Ar/ 39 Ar step-heating ages of ca. 48-36 Ma [28]. This documents basement overheating before Paleogene sedimentation, and this was most likely due to the late Eocene basement extension and exhumation.
The zircon (U-Th)/He thermo-chronology ages of 48-22 Ma in the Tatra Mts. are consistent with the extension and the Paleogene fore-arc sedimentation [74,75]. The apatite fission track ages range from 20 to 15 Ma, and apatite (U-Th)/He ages range from 18 to 14 Ma (l.c.). These ages overlap with the cooling ages of Tatricum and Infratatricum in the Považský Inovec and Malá Fatra Mts. [29,76,77].
The kalifeldspar 40 Ar/ 39 Ar age of 48 Ma from the Tatra Mts. [28] is compatible with 48 ± 2 Ma white mica plateau age from the Tatricum hanging wall blastomylonites in the Hrádok-Zlatníky shear zone ( Figure 5) at the contact of the Tatric Bojná and the Infratatric Selec blocks in the Považský Inovec Mts. [3,7]. Granodiorite blastomylonites at the Žiarska Valley pass in Tatra Mts., at the reactivated contact of the Upper and Middle Variscan units, could be of similar age. These 40 Ar/ 39 Ar ages of ca. 48-36 Ma [28] suggest final Tatricum and Infratatricum structuring in the Eocene.

Penninic, Infratatric and Tatric Units of the Malé Karpaty Mts.
The extremely compressed tectonic structure of the Malé Karpaty Mts. units resembles mélange type zones along the contact of the Penninic and Austroalpine units in the Eastern Alps; for example, from the Engadine and High Taurs tectonic windows (cf. [11] and references therein).
The south-western Malé Karpaty Mts. reveal the bottom Borinka Unit, likely representing a marginal part of the oceanic southern Penninicum (~Váhicum, after [8,9,78]). The northern-most inferred higher Infratatric Bratislava-Modra basement-cover nappe overlies the Penninic Borinka and the inferred lower Infratatric Orešany units, and in turn is overlain by the Fatric and Hronic nappes ( [16,79], and 1:50,000 Geological Map). Tatricum presence is not clear. Therefore, the Hainburg/Bratislava-Modra Nappe may be a part of the SW termination of the extended Tatric sliver, or this is already part of the higher Infratatricum. The structural position of the Borinka Unit partly resembles the Matrei Zone Penninic margin in the Tauern Window (cf. [11]]. The inferred Penninic oceanic rift likely continued along the front of the present-day Infratatricum [22]. The continental margin material occurs in the Jurassic scarp-breccias of the Borinka Succession [78]. The Infratatricum of the Malé Karpaty Mts. thus appears to have had the closest paleogeographic position to the oceanic southern Penninicum (~Váhicum after [9]).
The internal structure reveals the Hainburg/Bratislava and Modra-Orešany nappe units, including their deep-water cover successions (Devín and Kuchyňa or Solírov-Orešany, respectively), which overlie the Jurassic succession of the inferred Penninicum oceanic margin ( Figure 10). The higher, likely Tatric Kadlubka Succession is attached to the Fatric Nappe hanging wall. The general orogenic nappe structure was reported from deep reflection seismic cross-sections through the Malé Karpaty Mts. by [80].
Phengitic white mica from quartzitic meta-sandstones from the Hrubá Dolina Valley quarry near Pezinok township was 40 Ar/ 39 Ar-dated at ca. 73 Ma from the upper overturned limb of a recumbent fold in Figure 10. The dynamically recrystalized Qtz aggregates indicate a minimum temperature of around 250-300 °C for this common fold-thrust basement-cover structure [82]. This implies the closure of this inferred southern Penninic branch at ca. 90-80 Ma, followed by the north-Infratatric accretionary wedge formation.

Materials and Methods
The field investigation focused on the Infratatric, marginal Tatric and the inferred subautochthonous Fatric basement-cover structural complexes. Meso-and microstructures of representative rock-types which showed tectono-metamorphic overprinting were subjected to more detailed petrological and geochronological investigations.
The mineral composition and textures of the studied rocks were first investigated in polished sections by polarised light microscope. The mineral element compositions were measured by electron probe micro-analysis (EPMA) on a Cameca SX-100 electron microprobe at the State Geological Institute of Dionýz Štúr in Bratislava, and by JEOL Superprobe JXA 8100 at the Earth Science Institute of Slovak Academy of Sciences in Banská Bystrica (Slovakia). The EPMA was applied on white micas, chlorite, actinolite, epidote, apatite, titanite and albite. The voltage was accelerated by 15 kV, with a beam current of 20 nA focused to 3-5 μm, and the following standards and measured lines were used: Si Chlorite crystal formulae calculation was based on 14 anions and performed by Windows program WinCcac [83]. Micas were re-calculated based on 11 oxygens. The Chlorite and Mica classification is according to [84] and [85], respectively. Amphibole analyses were re-calculated by Excel Spreadsheet of [86] based on the classification of [87]. The metamorphic overprinting conditions were estimated by chlorite and paragonite-muscovite thermometers [70,71,73,88] and chlorite-phengite [73] and phengite [72] barometers combined with Perple_X pseudosection modeling.
Three meta-basite samples were used in the Perple_X modeling: One from the Infratatricum of the Považský Inovec Mts. Selec Block, and two from the subautochthonous Fatricum; one from the Tribeč Mts. Razdiel Nappe and one from the eastern Nízke Tatry Mts. Vápenica Nappe.
The studied rocks' original compositions were slightly modified to fit this 9-component system, as follows: (1) CaO was reduced according to bulk-rock phosphorous content, and assuming these elements were bound exclusively to ideally composed apatite and (2) the H2O contents were set in excess to enable free hydrous fluid phase formation at relatively low P-T. The pseudosections were contoured with isoplets for Mica and Chl chemical parameters using Perple_X werami and pstable sub-programs to supply raw data. The whole-rock composition of samples used for thermodynamic modeling are in Table S1 (Supplementary Materials).
Three samples and five mineral fractions were selected for the 40 Ar/ 39 Ar dating: Metaquartzite sample (ZI-3) containing a homogeneous aggregate of metamorphic white mica in recrystalized quartz aggregate; metamorphosed marly limestone (HC-12) containing white-mica rich layers in recrystallized calcite aggregates; schistose marble (SRB-1) containing two grain-size generations of white mica and one biotite generation in the recrystalized calcite matrix. Phengitic white mica aggregates of samples ZI-3, HC-12 and SRB-1 were chosen for constraining the age of Alpine metamorphism and related deformation stages. Muscovite and biotite fractions from sample SRB-1 were used for dating the inferred basement rocks' sources.
Optically fresh, unaltered and homogeneous grains of muscovite, biotite and phengite for 40 Ar/ 39 Ar dating were hand-picked from a 125-212 μm-size fraction under a stereomicroscope, then ultrasonicated and thoroughly rinsed in MilliQ water to remove impurities from the grains. 40 Ar/ 39 Ar dating was performed at the Western Australian Argon Isotope Facility at John de Laeter Centre (Curtin University, Perth). Multi-grain aliquots of the samples were loaded on an aluminium disc, with the GA1550 biotite standard (99.738 ± 0.100 Ma; [97] used as a flux monitor and irradiated for 40 h in the Oregon State University nuclear reactor (USA). All samples were unpacked after cooling for several weeks and individually loaded into copper (Cu) planchettes for analysis on the ARGUS-VI multi-collector mass spectrometer outfitted with four Faraday collectors and an ioncounting CuBe electron multiplier (CDD) at Curtin University. All analyses were conducted on single-grain aliquots, and this enabled direct determination of 40 Ar concentrations in single grains and prevented mixing of different age populations. Mica grains were analysed by incremental heating using a continuous 100 W PhotonMachine© CO2 laser GA1550. After heating, reactive gases were purified in an extra low-volume stainless steel extraction line of 240cc volume, using one SAES AP10 and one GP50 getter. The Ar isotopes were measured in static mode using a low volume 600cc Thermofisher© ARGUS VI mass spectrometer set with a permanent resolution of around 200 [98]. Measurements were performed in multi-collection mode using 4 Faraday cups with 1,012ohm resistors to measure 40, 38 and 37 masses and a 1,013-ohm resistor to measure the 39 mass. The 36 mass was then measured by ultra-low background compact discrete dynode ion counter. The relative abundance of each mass was measured simultaneously using 10 cycles of peak-hopping and 16 s integration time for each mass. Raw mass-spectrometer data were reduced using the Argus program written by M.O. McWilliams and run under a LabView environment. The raw data were processed using the ArArCALC software [99] and the ages were calculated using the decay constants of [97]. A neutron fluence parameter Jvalue (0.0109134 ± 0.06%) was calculated from standard grains within the disc. Mass discrimination was monitored regularly through the analysis using an automated air pipette, and this provided mean values of 0.993719 (±0.05%) per Dalton atomic mass unit relative to an atmospheric or trapped 40 Ar/ 36 Ar ratio of 298.56 ± 0.31 [100]. The correction factors for interfering isotopes were ( 39 Ar/ 37 Ar) Ca = 6.95 × 10 −4 (±1.3%), ( 36 Ar/ 37 Ar) Ca = 2.65 × 10 −4 (±0.84%) and ( 40 Ar/ 39 Ar) K = 7.30 × 10 −4 (±12.4%; [101]. All parameters and relative abundance values are provided in Table S2 following the recommendations of [102], and corrected for blank, mass discrimination and radioactive decay. The most distinct metamorphic textures were observed in the basement and cover rocks of the higher Infratatric Inovec Nappe. The more or less schistose Permian metabasalts are composed of Ep, Czo, Chl, Act, Ab, Cal, Ttn (leucoxene), Ap, Rt-sagenite, Mag and Cel-rich Ms (Ph). They have relics of magmatic Hbl, Cpx and Cr-Spl ( Figure 12A). Equivalent metamorphic textures, rich in newly formed white mica (mostly Ph), occur in Permian meta-rhyolites ( Figure 12B), meta-dacites ( Figure 12C), arkosic meta-sandstones ( Figure 12D) and Upper Carboniferous meta-sandstones ( Figure 12E).

Petrography, Mineral Chemistry and Tectono-Metamorphic P-T Conditions
The signatures of a low-temperature tectono-thermal overprinting are also visible in the Tatricum hanging wall granite blastomylonites according to newly formed aggregates of dynamically recrystalized Qzt, Ab, Chl and fine-grained white mica ( Figure 12F).
Less distinct but clear metamorphic textures were observable in Middle to Upper Jurassic cherty slates to meta-radiolarites and Lower Cretaceous cherty-clayey slates of the reconstructed deep-water Humienec Succession. These occur as clast-to-olistolith or tectonic fragments in the Upper Campanian to Maastrichtian "flysch" and they may have been derived from the frontal lower Infratatric Humienec thrust sheet. The very fine-grained white mica (Ilt-Ph) aggregates define S1 metamorphic schistosity planes which are often crenulated and crosscut with the S2 cleavage planes ( Figure 13A,B). Relic radiolarians are flattened and replaced by Qtz aggregates surrounded by newly formed white-mica (Ilt-Ph) aggregates in metamorphic S1 schistosity planes ( Figure 13C,D). Flattened and stretched coarse-grained Cal grains of Lower Jurassic crinoidal limestones are separated by the dynamically recrystalized Cal aggregates which contain newly formed metamorphic Ab and Qtz ( Figure 13E,F).
Similar distinct metamorphic textures were found in Couches-Rouges type marly slates. The samples were taken from a tectonic slice overlying the "flysch" in the Humienec thrust sheet directly in the footwall of the higher Infratatric Inovec Nappe. The Cal rich layers show dynamic recrystalization and newly formed Ab ( Figure 14A). Despite recrystalization and deformation, the foraminifers were preserved in some places ( Figure 14B). The presence of partly regenerated clastogenic Ms is characteristic in the newly formed finegrained white mica (Ilt-Ph) aggregates in the siliciclastic layers ( Figure 14C,D).   The transitional sedimentary-metamorphic textures are typical of the Upper Cretaceous flysch sediments hosting the clast to olistolithic fragments derived from the frontal Humienec thrust sheet and the rear Inovec Nappe, respectively. The "flysch" shales, sandstones and conglomerates are weakly deformed (Figures 11H,I and 15A-C). The Ms, Bt, Qtz, Kfs, Pl, Ch and Zrn clastogenic material in shales, sandstones and conglomerates is well preserved; for example, Bt is pleochroic and not chloritized ( Figure 15C). Rarely, foldcleavage structure formed ( Figure 15D). Calciclastic layers contain carbonatic clasts of variable grain-size and the well preserved clastogenic texture shows negligible Cal recrystalization ( Figure 15D). Newly formed very fine-grained white mica (Ilt to Ilt-Ph) aggregates are rarely observable ( Figure 15E). The "flysch" sandstone layers contain pebbles of micaschists and Middle-Upper Jurassic to Lower Cretaceous slates ( Figure 15F). BSE images, mineral chemistry and P-T estimates BSE images of investigated rock textures ( Figure 16) document newly formed metamorphic phases which were used for the P-T estimates from the higher Infratatric Inovec Nappe and the lower Infratatric Humienec thrust sheet.
Lower Cretaceous cherty-clayey slates of the lower Infratatric Humienec thrust sheet show crenulated S1 schistosity planes crosscut by S2 syn-metamorphic cleavage planes, and both plane systems are defined by newly formed Ilt-Ph and Chl fine-grained aggregates ( Figure 16F).
Upper Cretaceous flysch shales and sandstones of the Humienec thrust sheet show negligible metamorphic overprinting compared to the rocks of the higher Infratatric Inovec Nappe or the Jurassic-Lower Cretaceous clastogenic to olistolith fragments of the Humienec thrust sheet within the "flysch" matrix. There are observable mico-crenulated shales in some places, and these are composed of very fine-grained white-mica (Ilt to Ilt-Ph) aggregates ( Figure 16G). Well-preserved sedimentary structures of calciclastic and siliciclastic layers with Ms, Chl, Bt, Qtz, Fsp, Cal and Dol porphyroclasts are typical ( Figure 16H).  The results of geothermobarometric methods are based on metamorphic Chl and Ph or Chl-Ph pairs. The chemical composition of minerals including those used in Perple_X pseudosection modeling are available in Table S3.
Perple_X pseudosection modeling was used to estimate D1 stage P-T conditions of the Permian meta-basalts in the greenschist-facies metamorphic overprinting at 330-345 °C and 460-580 MPa pressure ( Figure 21, Table 2). These estimates also apply to the metabasalt olistoliths of the higher Infratatric Inovec Nappe in the Upper Cretaceous "flysch", and they agree with the results obtained by conventional Chl and Ph geothermometry within the given error.  Table S1.  Považský Inovec Mts. Hlohovec Block (Hlohovec Nappe and Jašter Thrust Sheet)
The most distinct metamorphic textures were observed in the higher Infratatric Hlohovec Nappe basement and cover rocks. The meta-aplite vein in granodiorite to tonalite is weakly deformed, with book-shelf structures of chloritized Bt, recrystalized Qtz and albitized feldspars ( Figure 22A). Newly formed white mica aggregates (Ph) occur in Lower Triassic meta-arkoses ( Figure 22B) and meta-quartzites ( Figure 22C). The Middle Triassic marble mylonites to ultramylonites contain very fine-grained white-mica (Ph) and partly recrystalized Dol porphyroclasts ( Figure 22D-E). The microfold core of inferred Lower Cretaceous marly marble contains white mica (Ph)-rich layers alternating with Cal layers, where the mechanical twins are oriented in axial-plane cleavage ( Figure  22G).
Couches-Rouges type marly slates of the lower Infratatric Jašter thrust sheet contain fine-grained siliciclastic layers composed of fine-grained aggregates of newly formed white mica (Ilt-Ph) and rarely Chl ( Figure 22H). BSE images, mineral chemistry and P-T estimates BSE images of the investigated rock textures (Figure 23) document the newly formed metamorphic phases used in P-T estimates.
The higher Infratatric Hlohovec Nappe Lower Triassic arkosic meta-sandstones show newly formed fine-grained aggregates of Ph and relics of clastogenic coarse-grained Ms ( Figure 23A). Lower Triassic meta-quartzite contains newly formed Ph, but also Ms clasts recrystalized into Ph + Pg aggregates ( Figure 23B). Middle Triassic marble mylonites contain coarse-grained Ph1 in the first S1 metamorphic schistosity planes. These planes with the segmented Ph1 are rotated in shear bands and crosscut by the mylonitic shear (C) planes defined with the recrystalized fine-grained Ph2 aggregates ( Figure 23C). Inferred Lower Cretaceous marly marbles are rich in one generation of metamorphic Ph aggregates with tiny relics of Ms. Fold-cleavage structure is characteristic ( Figure 23D).
Upper Cretaceous Couches Rouges marly slates of the lower Infratatric Jašter thrust sheet show less distinct metamorphic overprinting than the higher Infratatric Hlohovec Nappe rock group. However, the secondary very fine-grained white mica generation of the Hlohovec Nappe hanging wall marble mylonites appears comparable to the newly formed white micas of the underlying Jašter thrust sheet Couches-Rouges marly slates ( Figure 23E-G).
The geothermobarometric methods are applied to metamorphic Chl and Ph or Chl-Ph, and Ph-Pg pairs. The chemical analyses of representative minerals from the higher Infratatric Hlohovec Nappe and the lower Infratatric Jašter thrust sheet of the Hlohovec Block are available in Table S4.   (Table S4). Chlorite from the Hlohovec Nappe was not identified.  Figure 25B mostly fall within the higher anchi-metamorphism to lower greenschist facies fields with alkalis content of 0.9-1.0 K + Na p.f.u. and K2O up to 8.7-11.6 wt.%. Exceptions and marbles (SRB-1) cross both the lower and higher-T field with 0.77-0.95 K + Na p.f.u. This diagram compositionally displays two Ph generations in sample SRB-1 ( Figure 23C), and this is consistent with petrographic observations. The metamorphosed rocks of the Jašter thrust sheet contain Ilt-Ph. The compositions of the white micas in these rocks project along the muscovite-celadonite mixing-line in the classification diagram ( Figure 26A). SiO2 content in white micas from the Upper Cretaceous Couches-Rouges marly slates varies from 46.7 to 52.  (Table S4). Analyses of the Jašter thrust-sheet phengitic white mica mostly show values between 0.7 and 0.9 K+Na p.f.u. in Figure 26B, typical of lower anchi-metamorphism.  The geothermobarometry methods yield very similar P-T values ( Table 3). The temperature for Infratatric Hlohovec Nappe Lower Triassic quartzites (HC-14) was determined by Ms-Pg thermometry [88] and this yielded 280-283 °C at 600 MPa. Figure 27A (and Table 3) highlights pressure of 600 MPa (HC-14 and HC-15) at estimated temperature of 280-300 °C using Si-in-Ph geobarometry [72].The inferred recrystalization temperature of 220-250 °C for Jašter thrust-sheet Upper Cretaceous Couches-Rouges marly slates (HC-2, SRB-3) yields the pressures of 650-750 MPa based on Si-in-Ph geobarometry ( Figure 27B; Table 3). Upper Cretaceous "flysch" sandstone (JS-5) yields undistinct metamorphic overprint at inferred temperature below 200 °C. Figure 28A highlights that the metamorphic P-T conditions of the aplite vein (HC-19) in the Variscan granodiorite to tonalite in the higher Infratatric Hlohovec Nappe achieved 245 °C and 500 MPa using Chl-Ph pairs. Figure 28B constrains the Jašter thrustsheet Upper Cretaceous Couches-Rouges type marly slates (JS-2) P-T conditions to 269-278 °C and 510-620 MPa. This was accomplished with multi-equilibria Chl-Ph-Qtz-H2O geothermobarometry [73]. This temperature is consistent with an average temperature estimated by Chl geothermometry (Table 3).  [70,71,73] or estimated from mechanics of quartz dynamic recrystalization [105] in case of missing Chl in sample.

Petrography
The Zobor Nappe granitoid basement has varied deformation recrystalization from macroscopically undeformed or protomylonitic ( Figure 29A) to intensively mylonitized zones, with developed S-C structures indicating the NW-ward thrusting and top-to SE extensional sliding ( Figure 29B,C). Mylonitic foliation is covered by fine-grained aggregates of white mica and Chl, and the Qtz-Fsp porphyroclasts are prolongated in the NW-SE striking stretching lineation.
The sedimentary cover rocks are distinctly metamorphosed, and the schistosity planes are covered by white mica (Ms to Ph) and Chl. Schistose Middle Triassic marbles ( Figure 29D), and Lower Triassic meta-quartzites ( Figure 29E-G) are often re-folded with the basement mylonites.
The distinct metamorphic textures were observable in both the basement and cover rocks. Granodiorite to tonalite blastomylonites contain newly formed dynamically recrystalized Qtz, white mica (Ph), Chl, Ab, ±Ep, Czo, Cal ( Figure 30A-C). Albitized Fsp porphyroclasts are stretched and the fractures are healed by Qtz, Chl and Ph. Middle Triassic marbles have thin very fine-grained white-mica layers (Figure 30 D). Lower Triassic metaquartzites to quartzitic schists are rich in metamorphic white mica ( Figure 30E-H). The S1 metamorphic schistosity planes are often folded with developed S2 micro-fold axial-plane cleavage ( Figure 30E,F). Quartz porphyroclasts are dynamically recrystalized ( Figure  30H). BSE images, mineral chemistry and P-T estimates BSE images of investigated rock textures ( Figure 31) document newly formed metamorphic phases which were used for the P-T estimates.
Quartz, albitized Fsp, chloritized Bt and rare Ms porphyroclasts are surrounded by phengitic white mica and Chl aggregates oriented in schistosity planes of tonalite blastomylonites ( Figure 31A-C). Middle Triassic marble mylonites contain segmented Ph-rich layers and individual flakes disappeared in recrystalized Cal aggregates ( Figure 31D). Lower Triassic meta-quartzites to quartzitic schists and meta-sandstones contain fine-grained newly formed Ph less Cel-Ms in recrystalized Qtz aggregates ( Figure 31E-H). Folded quartzitic schists show syn-metamorphic cleavage planes S2 ( Figure 31E,F). Arkosic lithologies contain deformed Ms and Fsp porphyroclasts ( Figure 31H).   The applied geothermobarometric methods are based on the metamorphic Chl and Ph or Chl-Ph pairs. The chemical analyses of representative minerals from the Zobor Nappe are available in Table S5.

Petrography
The Razdiel Nappe shows distinct tectono-metamorphic overprinting of the basement and cover rock. Our research focused on the Alpine metamorphic overprinting textures in: (1) meta-granites to meta-tonalites ( Figure 36A  The Razdiel Nappe granitic rocks underwent varied deformational recrystalization to protomylonites and mylonites ( Figure 36A,B). Their blastomylonitic schistosity is defined by fine-grained aggregates of white mica (Ph), Chl, Ab, ±Ep, Czo and Cal and the Qtz-Fsp porphyroclasts are prolongated in the NW-SE striking stretching lineation. Quartz, Fsp and rare mica (Ms and chloritized Bt) porphyroclasts are stretched and fractured, and the fractures are infilled with the afore-mentioned newly formed phases. Phyllonitized micaschists are rich in fine-grain aggregates of Chl and white mica, and rotated Ab porphyroblasts ( Figure 36C).
The Permian meta-basalt intercalations have greenschist facies mineral assemblages of Chl, Ab, Act, Ep, Czo, ±Ph and Cal ( Figure 36D), and the meta-rhyolite consists of newly formed Ph, Chl, Ab, with relics of hypidiomorphic Qtz and sericitized Fsp. The schistosity planes of the Permian meta-sediments are covered by newly formed white mica (Ms to Ph) and Chl ( Figure 36E-G). A characteristic feature is the S2 syn-metamorphic crenulation cleavage crosscutting the S1 metamorphic schistosity ( Figure 36F). Crenulated metamorphic schistosity is also typical in the Lower Cretaceous slates ( Figure 36H). BSE images, mineral chemistry and P-T estimates BSE images of the rock textures ( Figure 37) document the newly formed metamorphic phases used for P-T estimates.
Tonalite protomylonites to blastomylonites ( Figure 37A,B) contain relics of albitized magmatic Fsp porphyroclasts, Qtz, chloritized Bt and rare Ms which are surrounded by oriented phengitic white mica and Chl aggregates in the schistosity planes. Phyllonitized micaschists are mostly composed of Qtz, Ph, Chl and Ab ( Figure 37C). Layered amphibolites are recrystalized to Act-Ph greenschists and still contain Hbl relics.
The Permian meta-basalts have a greenschist-facies mineral assemblage of Chl, Ab, Act, Ep, Czo, ±Ph, Cal and magmatic Hbl relics ( Figure 37D). Permian meta-sediments are rich in newly formed metamorphic Ph and Chl associated with Ab, Qtz and rare Cal (Figure 37E-G). Some of these exhibit S2 syn-metamorphic cleavage ( Figure 37F). Similar metamorphic textures also occur in the Lower Cretaceous slates ( Figure 37H), with relics of tiny Ms clasts in the newly formed anchi-metamorphic Ilt-Phe matrix.
The geothermobarometric methods were applied to Chl and Ph or Chl-Ph pairs. The compositions of representative minerals are available in Table S6.
The metamorphosed basement and cover rocks of the Tribeč Mts. Razdiel Nappe contain Cel-Ms. Figure 39A (Table S6). TiO2 content reaches 1.2 wt.%. Analyses of the white micas in Figure 39B mostly fall within higher anchi-metamorphism to lower greenschist facies with alkalis content of 0.9-1.0 K + Na p.f.u. and K2O up to 8.9-11.0 wt. %. Some samples are exceptions and cross both the lower and higher-T field down to the 0.86 K + Na p.f.u. level (Table S6).   The geothermobarometry applied to the basement tonalite to blastomylonites of the Razdiel Nappe yielded a relatively narrow pressure interval of 400-550 MPa at calculated average Chl temperatures of 308-365 °C ( Figure 40; Table 5). Micaschist phyllonites yield 400 MPa pressure at an average 342 °C temperature. Similar pressures were achieved by meta-sediments at 400 MPa and approximately 300 °C temperature (Table 5) based on Siin-Ph barometry [72]. Chl-Ph pairs in Permian meta-basalt (TRI-35, TR-33) generally yield higher P-T estimates at 700-750 MPa and average Chl temperatures 303-323 °C. Figure 41A-C highlights the metamorphic P-T conditions of meta-granodiorite (KAM-1) and meta-tonalite (LAM-1, CHD-2) of the Razdiel Nappe according to Chl-Ph pairs at 249-270 °C and 400-600 MPa. Micaschist phyllonites (NES-2, Figure 41E) were constrained at 252 °C and 400 MPa.  Figure 41G shows the inferred Low Cretaceous slate peak at 337 °C and 400 MPa. This was accomplished by multi-equilibria Chl-Ph-Qtz-H2O geothermobarometry [73].  [72] from the subautochthonous Fatricum of the Tribeč Mts. Razdiel Nappe. Temperatures derived from Chl thermometry by [70,71,73] or estimated from mechanics of quartz dynamic recrystalization [105] in case of missing Chl in sample.   Whole-rock composition used for modeling can be found in Table S1.  [105] in case of missing Chl.

Petrography
The inferred subautochthonous Fatric Vápenica Nappe is composed of thinned granodiorite-tonalite basement and the Permian-Lower Cretaceous cover rocks with distinct tectono-metamorphic overprinting. Our research focused on (1) mylonitized meta-granodiorites to meta-tonalites ( Figure 43A) and (2) the Permian meta-sediments and metavolcanics ( Figure 43B-D). The Vápenica Nappe sheared and strongly tectonically thickness-reduced granitic sole macroscopically exhibits a variable extent of deformational recrystalization in the granodiorite to tonalite protomylonites, mylonites and schistose blastomylonites ( Figure 43A), often with developed S-C structures indicating top-to-SE thrusting over the Veporic front. Blastomylonitic schistosity is covered by macroscopic fine-grained aggregates of white mica, Chl, Qtz, Pl/Ab, ±Ep and Cal and the Qtz-Fsp porphyroclasts prolongation is parallel to the (W)NW-(E)SE striking stretching lineation.
Tonalite and granodiorite mylonites of the Vápenica Nappe ( Figure 44A-D) show mylonitic/blastomylonitic schistosity defined by fine-grained aggregates of white mica (Ph), Chl, Ab, Qtz, Ep-Czo, ±Cld and Cal surrounding the porphyroclasts of relic magmatic Pl, Qtz, Ttn and Bt. The Qtz and Fsp porphyroclasts are stretched and fractured, and the fractures are infilled with the afore-mentioned newly formed phases. The brittle-ductile Fsp behaviour contrasts with ductile flow in the dynamically recrystalized Qtz aggregates.

BSE images, mineral chemistry and P-T estimates
Examples of BSE images of the investigated rock textures (Figure 45) document the newly formed metamorphic phases used for P-T estimates.
Granodiorite to tonalite blastomylonites ( Figure 45A) contains relics of albitized magmatic Fsp porphyroclasts, Qtz, chloritized Bt and rare Ms within the planar schistose domains defined by newly formed Ph-Chl aggregates associated with Qtz, Ab and Ep-Czo. The Permian meta-basalt shows the greenschist-facies mineral assemblage is composed of Chl, Ab, Act, Ep-Czo, Ph and Cal ( Figure 45B).
The applied geothermobarometric methods are based on using the metamorphic Chl and Ph or Chl-Ph pairs. The chemical analyses of representative minerals from the Vápenica Nappe are available in Table S6.
Perple_X pseudosection was used to estimate D1 stage P-T conditions of the Permian meta-basalts in the greenschist-facies metamorphic overprinting at 350-410 °C and 375-480 MPa pressure ( Figure 50; Table 6). The calculated equilibrium mineral assemblage is Chl-Ms-Ep-Bt-Ttn-Ab. These estimates coincide with results obtained by conventional Chl and Ph geothermometry within the given error.  Table S1. Table 6. Estimated P-T conditions from subautochthonous Fatricum basement and cover rocks in the eastern Nízke Tatry Mts. Vápenica Nappe.

Sample
Sample Description GPS Coordinates   The phyllonite S1 schistosity planes are refolded and crosscut by steeply south-dipping S2 axial plane cleavage ( Figure 51A). Crenulated metamorphic schistosity is observable in Permian meta-dacite ( Figure 51B). Staurolite-garnet micaschists show a gradual transition to Cld-Ph-Chl-Ab schists in phyllonite zones with distinct axial-plane cleavage of syn-metamorphic microfolds ( Figure 51C,D). Metamorphic schistosity of the Permian meta-volcanics and meta-granites is defined by greenschist facies minerals such as Chl, Ms and Ph, with Ab and less Ep group ( Figure 51E,F).

BSE images, mineral chemistry and P-T estimates
Examples of BSE images of the investigated rock textures (Figure 52) document the newly formed metamorphic phases used for P-T estimates.
Micaschist phyllonites ( Figure 52A,B) may contain relics of albitized Pl porphyroclasts, Qtz, chloritized Bt and phengitized St and Ms in the schistosity planes defined by newly formed Ph-Chl-Cld-Ab-Qtz aggregates. The Permian meta-dacite and metagranite contain the greenschist-facies mineral assemblage of Chl, Ab, Act, Ep-Czo, Ph and Cal ( Figure 52C,D). The applied geothermobarometric methods are based on the metamorphic Chl and Ph or Chl-Ph pairs. The chemical analyses of representative minerals from the Krakľová Nappe are available in Table S7.

Figure 55.
Pressure estimates diagram after [72] from subautochthonous southern Fatricum Krakľová Nappe in the eastern Nízke Tatry Mts. Temperatures derived from Chl thermometry by [70,71,73] or estimated from mechanics of quartz dynamic recrystalization [105] in case of missing Chl in sample.

New Mica 40 Ar/ 39 Ar Age Data from Subautochthonous Fatricum and Infratatricum and Their Interpretation
Grains of Ph (HC-12 and SRB-1), Cel-Ms (ZI-3), Ms (SRB-1) and Bt (SRB-1) for 40 Ar/ 39 Ar dating were hand-picked from a 125-212 μm-size fraction (see the Section 3.). Cel-Ms in sample ZI-3 seems to represent one deformation/recrystalization event or a Dstage ( Figure 56A). Similarly, homogeneous Ph aggregates in sample HC-12 appear to be products of one event or a D-stage ( Figure 56B). However, there are also visible dark 10-20 μm relic Ms flakes in the BSE image ( Figure 56B). Sample SRB-1 from the hanging wall of a marble thrust sheet overlying C.R. type marly slates ( Figure 8A) contains two grainsize Ph aggregates with most likely different ages. The dated coarse-grained Ph1 generation in the S1 schistosity is crosscut by shear bands with fine-grained Ph2 generation along the C-planes ( Figure 56C,D). The 40 Ar/ 39 Ar geochronology results from all dated samples are shown in Figure 57A-E, Table 8, and detailed in Table S2.
White mica of Cel-Ms composition from the ZI-3 meta-quartzite sample yielded a mini-plateau age (with 57% of the total 39 Ar released) of 62.21 ± 0.31 Ma (MSWD = 0.43, p = 0.95) which is interpreted to constrain the growth of the mica or complete recrystalization of the D1 Ph to Cel-Ms during the D2 to D3 exhumation stages ( Figure 57A). Lower Triassic meta-quartzite with Cel-Ms aggregates oriented in metamorphic schistosity S1. The subautochthonou Fatricum Zobor Nappe; (B) HC-12 Lower Cretaceous(?) meta-marly carbonates with homogeneous, often refolded Ph aggregates in the S1 schistosity crosscut by the S2 micro-cleavage. The higher Infratatric Hlohohec Nappe; (C,D) SRB-1 Middle Triassic schistose marble mylonite with two Ph grain size aggregates. Ph1 oriented in the main S1 schistosity; Ph2 occurs in shear bands parallel to the C-planes. The higher Infratatric Hlohohec Nappe.
Phengite from the HC-12 meta-marl sample failed to produce a plateau age and yielded a stair-shaped 40 Ar/ 39 Ar age spectrum with step ages around 85 and 125 Ma ( Figure 57B). The sample resolved an initial age of approximately 84 Ma before a gradual increase to around 96 Ma, with 79% 39 Ar released in 13 continuous steps. The step ages do not overlap because of precise errors resolved from high precision measurement. However, repeatable step ages ranging from 85 to 96 Ma from this sample show a consistency with the argon step ages produced from phengite sample SRB-1 (cf. below), before gradually increasing to an age of ca. 125 Ma in the last 6 steps with 12% of 39 Ar released. This type of spectrum is typical in mixed argon gas from different reservoirs, and it may suggest two distinct mica generations, or two distinct tectono-thermal events recorded by a single mica generation.
Phengite from the SRB-1 marble mylonite sample did not yield a plateau age, but produced consistent apparent ages clustered around 90 Ma with 74% 39 Ar released in 10 continuous steps ( Figure 57C) which can be tentatively interpreted as recording the phengite growth age. This sample's failure to produce a plateau age is due to the high precision of each step-age analysis and a little overlapping of the precise age errors. The step-ages gradually increased in the last 7 steps with 8% 39 Ar released and produced a stair-shaped 40 Ar/ 39 Ar age spectrum reaching approximately 110 Ma. It can be considered that the failure to reveal a plateau with >70% of the total 39 Ar released was due to the presence of excess Ar and/or alteration, or alternatively, the apparent age spectrum may be a mixture between two age members of ca. 110 and 70 Ma which would be removing any geological significance to the ~90 Ma apparent cluster of step age around ~90 Ma. Furthermore, it is important to note that experimental works have shown that mixture of components with two different ages tend to produce sigmoidal-shape age spectrum such as this one [106]. A mixture interpretation is consistent with the presence of an older metamorphic Ph1 most likely related to the burial (D1) within the Albian-Cenomanian/Turonian accretionary wedge. On the contrary, a younger Ph2 is closely related to the lateto post-Campanian thrust fault formation over the C.R. of the Santonian to Early Campanian age (Figures 8A and 56C,D).  Biotite and Ms from sample SRB-1 yielded complex, irregular apparent age spectra with no well-defined plateau ages typical for argon mixed from multiple reservoirs during step-heating experiments (e.g., [107]). Although these results prevent robust interpretation and may be disregarded, the apparent age spectra range from ca. 350 Ma (Bt) and ca. 270 Ma (Ms) to ca. 45 Ma. This range may suggest that the analysed samples contained multiple generations (i.e., partial recrystalization) of mica formed during the Variscan to Alpine orogenies. Most likely clastogenic relics of Ms and Bt in SRB-1 marble mylonites may indicate their origin from the Variscan basement rocks such as granites and gneisses. These micas then have young ages due to Alpine tectono-metamorphic events registered in the Infratatricum.

Applied Methods for Metamorphic P-T Estimates
Determining the P-T condition in low-grade metamorphic rocks (up to "epizone" T < 350 °C) is challenging because of the lack of indexing minerals and other factors (e.g., Bourdelle, 2021). This has mostly been achieved in the past decades by several calibrations of chlorite thermometers and phengite barometers (e.g., [70][71][72]108]). LT-LP chlorite thermometry, however, is still open to debate [109][110][111]. Two main approaches are still used today.
The conventional approach using Al IV increase, and octahedral vacancy decrease with increasing temperature originally described by [108] and several re-calibrations using different corrective factors based on the Fe/Mg ratio (e.g., [70,71,112]). A new thermodynamic approach has also been developed for low-grade metamorphic rocks [73], and this mostly involves a chlorite thermometer which enables XFe 3+ Chl estimation at fixed pressure [73,113]. This approach is most rigorous, but it has problems with lacking thermodynamic data for Si-rich members which limits its use to chlorites with Si under 3 p.f.u.
A similar development is described for pressure estimates. Widening the miscibility gap between muscovite and celadonite with either rising pressure or decreasing temperature was initially reported by Velde [114,115], thus confirming the pressure dependency of Si 4+ in Ph used in the geothermobarometry of phengite-bearing metamorphic rocks [72,116,117]. The reaction of this barometer (3Qtz + 2Kfs + Phl + 2H2O = 3AlCel) depends on the coexistence of Ph with Phl, Kfs and Qtz and water activity (Ptot = PH2O). We assume that the H2O = 1 condition was met for the studied samples because they all contain a greater number of water-bearing minerals. The required assemblage was not present in all samples. However, according to [72], we can derive at least minimum pressures from the Ph that coexists with other Fe, Mg silicates such as Chl, and not with this limiting assemblage [72]. We selected the samples that seemingly follow both requirements for Siin-Ph barometry. This method appears satisfactory for most of our studied samples with reasonably calculated pressures (Figures 19,27,34,40,48 and 55; Tables 2-7). However, some meta-sandstones (i.e., VV-82, VV-23) and clayey-rich layers in C.R. type marly slates (i.e., HC-2, PI-39) exhibit systematically very high or overestimated pressures (Figures  19,27 and 48, Tables 2,3,6,S4,S5 and S7). We assume that this can be caused by the composition deviating from the barometer calibration or the very Si-rich nature of the protoliths which could cause additional Si-enrichment of the Cel-Ms (Ph) in some samples. Like chlorite, a thermodynamic approach on K-white mica thermobarometry was employed by [91] which enabled P-T derivation by combining the Chl-Qtz-H2O thermometer and K-white mica Qtz-H2O barometer [73].
We therefore employed a combination of the described methods to avoid the limitations in these approaches and obtain the biggest possible dataset of P-T estimates. All the studied chlorites have the low Al IV typical for low-temperature crystalization [108] and all results from conventional thermometry are consistent within error (±50 °C) with the multiequlibria thermometry by [73]. The results in Tables 2-5 show that some temperatures calculated by Chl-Qtz-H2O (Chl V ) equilibria give different temperature interval (usually lower) than the combination of Chl-Phg-Qtz-H2O (Chl-Ms (V) ) equilibria. We assume that this is due to the following: (1) The Chl-Qtz equilibrium is constrained by two independent equilibria while the Chl-Ph-Qtz equilibria are constrained by four equilibria. Hence, when we combine these minerals, we increase P-T estimate robustness but simultaneously increase result-error. (2) The Chl-Qtz equilibrium is at lower temperatures than Chl-Ph-Qtz equilibria. This method was primarily calibrated for meta-pelitic rocks, so it is reasonable to assume that it is best for samples such as meta-sandstones, meta-arkoses and flysch slates and samples that are compositionally close to these lithotypes ( Figures  18,28 and 41); we were mostly unable to get realistic results, or none, when we used this method for other samples. Moreover, the pressure estimates calculated by Chl-Ph-Qtz-H2O geothermobarometry appear more reasonable if we expect the [72] barometry results to reflect maximum pressures for the studied samples mostly within 200 MPa error and greater than minimum pressure.
The achieved anchi-metamorphic to low-greenschist condition of the studied samples is further confirmed by typical transitional Ilt-Ph composition with decreased (K + Na) and K2O contents (Figures 18,25,26,33,39 and 47, Tables S3-S8) [69,104]. Since many samples lack Chl, this and dynamical recrystalization of Qtz [105] were the only options to obtain at least estimated temperatures. The correlation between illite crystallinity and mica K2O content was described from the diagenetic grade to the epizone by [103], where the occupancy of the interlayer position of the micas gradually increases and the (K + Na) content of the illite-muscovite increases [118][119][120]. In the sample SRB-1 with the two Ph generations ( Figure 56C,D) the coarse-grained Ph1 shows the higher Si (3.4-3.5 p.f.u.) and Na + K values in comparison with the deformed Ph1 porphyroclasts and the recrystalized fine-grained Ph2 in the shear bands which show a decrease in Si to ca. 3.2 p.f.u. and Na + K ( Figure 25). An increase of Fe + Mg in Ph2 ( Figure 25) is likely also related to the deformational recrystalization (e.g., [121]).
Perple_X pseudosection modeling of the Považský Inovec Mts. Permian meta-basalt sample (PI-B3) was published by [3]. However, the changes in database and related solution models can produce smaller to larger differences in the calculated pseudosections e.g., [122], therefore we decided to update the pseudosection modeling with [95,96] solution models and the related [94] database to keep it in par with other modelled samples (HEL-1-1, TR-35, Figures 42 and 50). The calculated results of 330-345 °C and 460-580 MPa ( Figure 21) overlap within the given errors with conditions of 308-315 °C and 490-610 MPa reported in [3]. Calculated stable mineral assemblages also match (Amp-Chl-Ms-Ab-Pu-Bt) except for Cpx which often tended to be over stabilised (especially in metabasic rocks) when the older Cpx(HP) model was used [92,123]. This then caused most of the changes in the topology of both pseudosections.
The metamorphic conditions were most precisely estimated by Perple_X pseudosection modeling and these, however, are related only to the D1 syn-collision burial stage of the three chosen structural units, one from the Infratatricum (PI-B3, Figures 21,58) and two from the subautochthonous Fatricum (TR-35 and HEL-1-1, Figures 42,50,58) to provide evidence on their participation in the inferred Albian-Cenomanian/Turonian accretionary wedge constrained by the new 40 Ar/ 39 Ar geochronology data ( Figure 57B-C). The estimated P-T conditions of the many remaining structural units using the various geothermobarometry methods discussed above are reviewed in Tables 1-7, and here we recommend considering the average values within the error.
The medium-pressure lower-temperature greenschist-facies metamorphic conditions were determined from the deepest buried fragments of the basement and the Upper Paleozoic cover rocks with similar mechanical behaviour. Some Lower Triassic quartzite fragments with newly formed Ph show similar burial depths compared to those containing metamorphic Ms instead of higher-pressure Ph. Similarly, most of the Middle Triassic marbles are Ph bearing. These rocks may record the D1 stage metamorphic conditions constrained by several white mica (Ph) plateau ages at ca. 100-90 Ma [3,7], including the newly obtained ages from the HC-12 and SRB-1 Infratatric samples. In contrast, most of the Jurassic to Cretaceous slates contain newly formed Ilt-Ph in addition to remnants of Ms microclasts, thus indicating relatively shallower burial depths and maximum higher anchi-metamorphic conditions. However, the Upper Cretaceous "flysch" sediments contain only Ilt to Ilt-Ph and reflect only the boundary diagenetic/lowest anchi-metamorphic conditions ( Figure 58A-H).  [88], T*-average of calculated T or estimated T from mechanics of quartz dynamic recrystalization [105] in case of missing Chl.
We focused mainly on structural units exhibiting the metamorphic structures representative of the D1 stage ( Figure 58A-E), although we locally could document also the metamorphic or mylonitic textures of the D2 exhumation. Despite some overlapping the P/T we can conclude that the pressure is decreasing from the wedge rear subautochthonous Fatricum to the Infratatricum wedge front. Cel-Ms from ZI-3 meta-quartzite of the subautochthonous Fatricum Zobor Nappe may document D1 shallower burial depths, while Ph from HR-1 meta-quartzite indicates much deeper part of this nappe. However, the age of the ZI-3 sample Cel-Ms of ca. 62 Ma does not fit to the D1 stage and may record a late D3 exhumation stage. Similar trend of the decreasing temperature towards the front is also characteristic of the accretionary wedges. This trend indicates a relatively deeper burial of the subautochthonous Fatricum due to inferred distinctly thinned a pre-metamorphic basement. Moreover, the exhuming ductilely deformed Veporic basement was a more effective overload in the rear part of the D1 wedge in comparison with thicker and mechanically harder Tatric sliver overthrusting the Infratatricum later, in the D3 stage ( Figure 60, cross-section D). Thus, Figure 58F highlights partly overlapping P/T conditions of all accretionary wedge structural units for the D1-D2 stages. The C.R. marly slates record the D3 stage at higher anchi-metamorphic temperatures and medium pressures ( Figure 58G). They occur as individual tectonic bodies of the lower Infratatric thrust sheets ( Figures 5-8) due to inferred thinned rugged basement detachment and underthrusting below the higher Infratatric nappes. Figure 58H highlights indistinct metamorphic overprinting of a frontal "flysch" basin infill during the D4 stage.

Fatric-Tatric-Infratatric Evolutionary Stages Constrained by Published and New 40 Ar/ 39 Ar Ages
The Fatricum in our model also includes the so-called "northern Veporicum" area, and these terms are synonymous for the same Late Cretaceous structural zone. We therefore recommend avoiding the use of "northern Veporicum" and substitute it by Fatricum as a structural unit equivalent to the Infratatricum, Tatricum, Veporicum and Gemericum which are composed of basement-cover structural units such as nappes, structural complexes or thrust sheets. We can distinguish these IWC northern zones paleogeographically with the following Jurassic-Cretaceous basin cover successions: Borinka Succession of the inferred southern Penninic oceanic margin, Orešany Succession of the Infratatricum continental margin facing the Penninic Realm, intra-continental Tatra and Šiprúň basin successions of the Tatricum and Vysoká, Manín, Zliechov, Veľký Bok and Humienec(?) type successions of the intra-continental Fatric Basin which transformed into a number of structural complexes described in this paper.
In addition, this "northern Veporicum" term does not fit with the mountain geography being part of the Nízke Tatry (Low Tatra) Mts., and the Veporicum occurs between the Late Cretaceous Pohorelá and Lubeník thrust faults in the Vepor Mts. The Foederata cover of the Veporicum is different to that of the Fatricum/"northern Veporicum" in the missing Jurassic-Cretaceous succession, most likely due to the commencing Jurassic compression and the formation of the southern Neotethyan wedge. Even the Upper Triassic successions are different (e.g., [8]). However, the typical allochthonous Fatricum occurs in the form of the Krížna Nappe system overlying the Tatricum; typically, in the Veľká and Malá Fatra Mts.
There is no lithostratigraphic or geochronologic evidence for "northern Veporicum" (~Fatricum) participation in the southern Neotethyan wedge with the Veporicum south of the Pohorelá line. In direct contrast, participation of the southern Veporicum in the Neotethyan Meliatic-Gemeric-Veporic wedge [4 and references therein] is constrained by the phyllonite white mica 40 Ar/ 39 Ar plateau age of ca. 124 Ma (124.2 ± 3.6 Ma; [7]) and the Permian meta-rhyolite in situ EPMA monazite age of ca. 130 Ma from the Vepor Mts. Fabova Hoľa Massif [35]. These ages suggest that only the Veporicum south of the Cretaceous Pohorelá thrust fault was incorporated in the southern wedge contemporaneously with the growing Fatric Basin towards the north. The formation of the southern Neotethyan wedge terminated at ca. 100 Ma [3,4,7,34], and the compression-deformation regime moved northwards to the Fatricum. Consequently, the Fatric Basin's extensionally thinned basement was underthrust beneath the Veporicum, thus initiating Veporic exhumation between approximately 100 and 85 Ma according to the white-mica 40 Ar/ 39 Ar plateau ages reported from the "southern" Veporicum [7,24]. The underthrust Fatricum may have blocked inferred an orthogonal N-ward collision which changed to a sinistral transpression in the exhuming south-Fatric rear (e.g., [41,124,125]), while the Veporicum south of the Pohorelá line underwent top-to-ESE(SE) structural unroofing [125,126]. Moreover, this important tectonic boundary indicates a change from the Early Cretaceous thickskinned tectonics in the newly defined Veporicum to the Late Cretaceous thin-skinned tectonics in the Fatricum [41,43,125,127]. Thus, the Pohorelá (master) thrust fault is one of the major tectonic boundaries of the IWC separating the southern Neotethyan and the northern Atlantic (Alpine) Tethys wedges or continental microplates. Consequently, the whole zone between the Pohorelá and Čertovica thrust faults can be considered the root zone of huge Fatric nappe system.
The maximum (D1) white mica 40 Ar/ 39 Ar plateau ages of 93.2 ± 1.5 and 91.9 ± 2.3 Ma [7] in the newly defined Fatricum of the eastern Nízke Tatry Mts. north of the Pohorelá line overlap with the exhumation (D2) ages of the Veporicum south of the Pohorelá line, and these 40 Ar/ 39 Ar ages are consistent with the Fatric Basin closure and the Fatric nappe formation. Therefore, the Veporicum may have acted as a "back-stop" domain during the closure of the Fatric Basin and the southward underthrusting of the Fatric basement-cover complexes underneath the Veporicum.
Both the Tribeč Mts. Zobor and Razdiel nappes could be the exhumed subautochthonous Fatricum. The Razdiel Nappe, composed of the strongly blastomylonitized basement and the Veľký Bok type Veľké Pole Permian-Mesozoic cover [45] most likely derived from the southern basin margin, resembling the Fatric, although finally south-vergently thrust Vápenica Nappe over the south-Fatric Ľubietová and Krakľová nappes. In contrast, the variably deformed protomylonitic to blastomylonitic granitic basement, with the metamorphosed shallow-water Mesozoic cover of the Tribeč Mts. Zobor Nappe, may be the northern basin margin, facially resembling the south-Tatric swell. The central deep-water Zliechov Succession was transformed into the superficial Fatric Krížna Nappe system because the strongly thinned central Fatric basement was almost completely underthrust below the Veporicum. An approximately 10-km thick reflection horizon of this underthrust inferred strongly blastomylonitized basement was recorded in reflection seismic cross-Section 2T [127].
Both Tribeč nappes achieved a similar medium pressure greenschist facies tectonometamorphic overprinting grade, with the 40 Ar/ 39 Ar white mica plateau ages of ca. 80-70 Ma [7,27]. The 40 Ar/ 39 Ar plateau age of 80.2 ± 1.1 Ma of Ph from the Razdiel Nappe blastomylonitized tonalites (CHD-1; [7]) is younger than the white mica plateau ages from the south-Fatric Krakľová Nappe (ca. 93-84 Ma; [7]), but older than the white mica plateau age from the blastomylonitized granitoids of the Zobor Nappe (71.4 ± 0.7 Ma; [27]). The age sequence between ca. 90 and 70 Ma may document gradual exhumation (D2 to D3) of the subautochthonous Fatricum, most likely in a transtensional regime and general SEward Veporicum sliding. The Zobor Nappe thus resembles an exhumed core-like complex from below the Razdiel Nappe which slid with the inferred Veporicum above them. Although the small Razdiel Nappe Mesozoic cover thrust sheets overlie the Zobor Nappe, the typical detached unmetamorphosed Fatric nappes generally overlie only the Tatricum towards the north ( [18]; Map 1:50,000).
The new Cel-Ms 40 Ar/ 39 Ar mini-plateau age of ca. 62 Ma from the Zobor Nappe (ZI-3 sample of Lower Triassic meta-quartzite from Žirany quarry in the Tribeč Mts.) is the youngest age reported so far for the subautochthonous Fatricum. This age may suggest the wedge rear Fatricum tectono-thermal reactivation contemporary with the Infratatric trench-like Belice "flysch" trough closure, and the Infratatricum accretion to the Tatricum (Figures 59 and 60). The overall compression/transpression regime finally led to the (late-D3) fan-like structure formation of the subautochthonous Fatricum rear which bivergently overthrust the Tatricum and Veporicum. However, the ductile regime of the Vápenica Nappe back-thrusting towards the SE/ESE is limited by the ZFT ages of the southern Fatricum (former northern Veporicum) at ca. 75-65 Ma [77,128], the latter ages indicating the already advanced exhumation and cooling of the northern wedge hinterland.
The extensional exhumation (D2) of the subautochthonous Fatricum at ca. 90/85-75 Ma constrained by white mica 40 Ar/ 39 Ar data occurred during the collapse of the Albian-Cenomanian/Turonian accretionary wedge front, contemporary with the start of the south-Penninic subduction beneath the Infratatricum in the north. This agrees with the widespread regional extension related to Gosauian basin formation in the Eastern Alps (e.g., [24,129]) and it is most likely that this type of basin, including the Belice Basin, also formed in the IWC above the inferred Penninic-Váhic subduction zone.
The Tribeč Mts. ZFT and AFT ages are in the 70-55 Ma and 45-35 Ma intervals, respectively [76,77]. The pseudotachylytes in granodiorite from the Tribeč Mts. Zobor Nappe, dated at 58 and 46 Ma by 40 Ar/ 39 Ar document a significant Eocene seismogenic event [130] which we relate to the collapse of the IWC Eocene orogenic wedge.
The central Tatric sliver north of the subautochthonous Fatricum has weak tectonothermal overprinting according to the typical ductile-brittle deformation structures. An older apparent ZFT age of ca. 102 Ma was determined from deformed granitoids of the Žiar Mts. [131]. A similar 40 Ar/ 39 Ar step age cluster of ca. 100 Ma was determined from the hanging wall blastomylonites of the Tatric Panská Javorina Nappe overlying the higher Infratatric Inovec Nappe in the middle part of the Považský Inovec Mts. [7]. These rare apparent ages may indicate burial of some parts of the central Tatricum sliver below the overthrusting early Fatric nappes in the forming Albian-Cenomanian/Turonian wedge. In contrast, the approximately 80-73 Ma 40 Ar/ 39 Ar plateau ages from the Infratatricum of the Malé Karpaty Mts. [7] may indicate the formation of the frontal Infratatric edge adjoining the inferred subducted south-Penninic (Borinka Unit) oceanic margin.
A similar D1 stage at 101 ± 2.9 Ma plateau 40 Ar/ 39 Ar and 102 ± 4 Ma ZFT ages were found from Permian meta-sandstone of the higher Infratatric Inovec Nappe [3] in the central part of the Považský Inovec Mts. The increased 40 Ar/ 39 Ar plateau age of 114 ± 2.4 Ma determined from a Lower Cretaceous slate olistolith in the Upper Cretaceous "flysch" of the lower Infratatric Humienec thrust sheet most likely reflects recoil effect (l.c.).
The two new white mica samples with apparent 40 Ar/ 39 Ar ages clustering at ca. 90 Ma from the higher Infratatric Hlohovec Nappe marble thrust sheet (HC-12 and SRB-1; Figures 56B,C and 57B,C) may still belong to the D1 stage, indicating the present-day Infratatricum participation in the Albian-Cenomanian/Turonian wedge. This age is however, interpretable as a mixture from the D1 and D3 tectono-metamorphic stages recorded in the Ph-bearing D1 and D3 microstructures ( Figure 56C,D). The 40 Ar/ 39 Ar plateau ages of ca. 100-90 Ma [3,7] are consistent with termination of the Jurassic to Lower Cretaceous inferred Fatric Humienec Succession and stratigraphic hiatus before the Upper Cretaceous C.R. type marls and "flysch" deposition already in the Tatricum foreland Infratatricum. Moreover, metamorphosed olistolithic and tectonic fragments of the basement micaschists and the Permian to Lower Cretaceous cover rocks occur in almost unmetamorphosed "flysch" pelagites [3,57,132].
The formation of a fore-arc type Infratatric Belice Basin (D2) may suggest the southward subduction of the southern Penninicum beneath the Albian-Cenomanian/Turonian wedge at ca. 90-75 Ma that is the time of the Belice Basin formation. The change in hemipelagic sedimentation of the Couches-Rouges type marls (C.R.) to deep-water calciclastic and siliciclastic "flysch" sediments most likely indicates the change from an extension to compression regime in the latest Cretaceous and the transformation (D3) of the Belice Basin to a "flysch" trough. The D3 compression may have been accompanied by underthrusting of the C.R. marls underneath the higher Infratatric Inovec and Hlohovec nappe system and the lower anchi-metamorphic slaty cleavage formation in the C.R. This deformation regime change might have been related to ceasing foreland Penninic subduction, and thus the supra-subduction extension termination. However, direct superposition of the "flysch" on the C.R. type marls was not observed, and the marble thrust sheet of the Hlohovec Nappe, for example, directly overlies (D3) the C.R. anchi-metamorphosed marls. Similarly, the Inovec Nappe Hradisko Hill Triassic cover thrust sheet overlies the "flysch" and the lower anchi-metamorphosed C.R. marls fragments north of Humienec Hill (Figures 5-8). In addition, the differences in the metamorphic overprinting may indicate different burial ages of these Upper Cretaceous successions: the late Campanian to Maastrichtian at ca. 75-65 Ma for the C.R. marls (D3), and the Paleocene to Eocene at ca. 65-50 Ma for the "flysch" (D4). A lower anchi-metamorphic overprinting of the C.R. contrasts with the diagenesis to lowest anchi-metamorphic overprinting of the "flysch".
Finally, during the D4 stage, the higher anchi-metamorphic to low-grade basement and cover rocks of the higher Infratatric Inovec and Hlohovec nappes and the hanging wall Upper Cretaceous anchi-metamorphosed C.R. overthrust "flysch" sediments. The rugged basement fragments of the lower Infratatric Humienec and Jašter thrust sheets often occur directly in the Upper Cretaceous sediments, and the whole arrangement thus has a mélange character after the D4 stage, observable for example, in the Hlohovec Block and north of the Humienec and Hradisko hills in the Selec Block (Figures 5-8).
The Infratatricum exhumation at ca. 50-40 Ma (D5) was determined by the 48.3 ± 2.2 Ma Cel-Ms 40 Ar/ 39 Ar plateau age from the Tatricum hanging wall leucogranitic blastomylonites (PI-17HZ; [7]), and the 57-37 Ma ZFT ages from the Infratatricum footwall [3]. The latter event is most likely related to collapse of the Eocene wedge and development of wedge-top basins in response to subduction of the north-Penninic Magura Basin of the Outer Western Carpathians underneath the IWC (cf. [133]). The main interval of ZFT ages of ca. 77] suggests the D5 Eocene exhumation and cooling of the Infratatricum in the Selec Block. The AFT ages of 21-13 Ma [76,77] indicate final Miocene exhumation and cooling of the Infratatricum and the overlying Tatricum of the Bojná Block. ZFT ages are missing in the Hlohovec Block, and the AFT ages are in the 50-40 Ma interval [76,77].
Characteristic fold-and-thrust tectonic style is observable in the Infratricum and subautochthonous Fatricum with variable metamorphic overprinting grade (Section 4.1) of structural units (Figure 58). The lower-temperature thin-skinned tectonics [134,135] is typical of the Albian-Cenomanian/Turonian accretionary wedge. It is inferred that the syncollisional burial (D1) was accompanied by detachment faulting and decoupling of the basement and cover rocks due to different mechanical behaviour and buoyancy. Moreover, several mechanically weak lithological zones may have been utilized at the formation of the Mesozoic Fatric nappes [15]. Blastomylonitic zones in the basement rocks are indicators of such zones typically developed in the subautochthonous Fatricum, Infratatricum and the base of the Tatricum (Sections 2 and 4). The Infratatricum resembles the "supratatric" subautochthonous Fatricum in many aspects, especially for example when considering the similarities in the tectonic structures set out in the Sections 2. and 4., and the D1 stage metamorphic conditions depicted in Figure 58. Such close relationships between the Infratatricum and subautochthonous Fatricum could be evidence of a close tectonic position of the higher Infratatric and subautochthonous Fatric basement-cover nappes in the Albian-Cenomanian/Turonian wedge during the D1 stage. So far geological interpretations could not explain the older ca. 100 Ma Ar/Ar ages in the north (in the higher Infratatric nappes) within this N-ward progressing accretionary wedge. Moreover, considering Tatricum overload on the Infratricum at ca. 100 Ma contradicts the stratigraphic extent of the northern Tatricum autochthonous Mesozoic cover up to the Turonian in the Tatra and Veľká Fatra Mts. [64,65]. In addition, the central Tatricum sliver as mechanically strong and internally without a distinct tectono-metamorphic overprint could hardly been separating two domains of similar but much more distinct overprint in the wedge D1 stage. This is fact that the D1 Ph ages: 101.2 ± 2.9 Ma plateau age (with 94% 39 Ar released) determined from the higher Infratatric Inovec Nappe Permian meta-sandstone and 106.2 ± 3.7 Ma plateau age (with 81% 39 Ar released) from the Inovec Nappe Lower Cretaceous slate olistolith in Upper Cretaceous "flysch" of the lower Infratatric Humienec thrust sheet are about 10 Ma older than the approximate 90 Ma ages determined from the Krakľová Nappe in the south [3,7]. This may indicate that the present-day higher Infratatric nappes and the Klape nappe with the Albian-Cenomanian "flysch" containing the Neotethyan wedge material [3,5,13] both derived from the area south of the Tatricum (Figure 59). Although the Albian-Cenomanian "flysch" in the Infratatricum of the Považský Inovec Mts. is missing, it occurs in the close Infratatric foreland Klape Unit (Figure 60), and these inferred early Fatric nappes must have overthrust the Tatric sliver terminated edges before the Belice Basin opening in the late Turonian/Coniacian. Evidence for this is provided by the C.R. type marls occurring only north of the Tatricum which secondarily overthrust the Infratatricum in the D3 stage (Figures 59 and 60). This is also suggested by the (pre-D3) deep-water Turonian-Santonian succession [17] deposited at the Tatricum northern edge which is now exposed in the middle part of the Považský Inovec Mts. Bojná Block. Therefore, a separated (Humienectype?) part of the Fatric Basin s.l. in direct proximity to the Neotethyan wedge cannot be excluded. The Pohorelá thrust fault may be a suture zone which formed after this basin closure and expulsion of the present-day higher Infratatric and the Klape nappes. The Humienec Basin may then have been part of a more complex intracontinental Fatric riftogenic basin system along the Tatricum southern margin, while an oceanic Váhic-S-Penninic riftogenic basin ran around the Tatricum northern margin, and both basin systems formed part of the Atlantic (Alpine) Tethys. Although, this paragraph´s speculations of the first author may be not soundly based at this investigation stage, this is an alternative interpretation of the very close structural, metamorphic, and geochronological relationships between the Infratatricum and the "supratatric" subautochthonous Fatricum in the proposed evolutionary model depicted in Figure 60.


Thermodynamic modeling, geothermobarometry and white mica 40 Ar/ 39 Ar dating constrain the metamorphic conditions and evolutionary (D) stages of the structural units which formed due to closure of the Jurassic-Cretaceous Atlantic (Alpine) Tethys basin system and subsequent opening and closure the Upper Cretaceous basin system in the northern part of the IWC (Figures 58-60).  The metamorphic conditions determined from the Permian meta-basalts of the Infratatricum and subautochthonous Fatricum by Perple_X modeling are very similar (within the error of the applied methods), indicating the D1 stage or syn-collisional burial in the Albian-Cenomanian/Turonian accretional wedge. The subautochthonous Fatric structural units provided the pressures of 400-700 MPa at 250-410 °C by the Perple_X modeling (Razdiel and Vápenica nappes), Chl-Ph geothermobarometry, Chl geothermometry and Ph geobarometry. The higher Infratatric nappes achieved 400-600 MPa at 250-350 °C that was constrained by the Perple_X modeling (Inovec Nappe), Chl-Ph geothermobarometry, Chl and Ph-Pg geothermometry and Ph geobarometry. Such small differences in the estimated P/T conditions for most of the nappes after the D1 stage indicate their neighbouring position in the Albian-Cenomanian/Turonian wedge, in general, south of the Tatricum and beneath the Veporicum ( Figure 60, cross-section C). The present-day higher Infratatric Inovec and Hlohovec nappes and the Manín-Klape nappe units achieved the Infratatric position in the D1 wedge front by the overthrusting the Tatricum terminated edges yet before the opening of the Belice Basin. The Infratatric nappes were secondarily overthrust by the Tatricum during the D3 stage (Figures 59 and 60, cross-section D).  The D1 event was 40 Ar/ 39 Ar dated on phengitic white mica to two ca. 90 Ma apparent step ages from the higher Infratatric Hlohovec Nappe marble thrust sheet (SRB-1 and HC-12 samples). We interprete this age of ca. 90 Ma as a mixture of Ph ages from the D1 and the D3 tectono-metamorphic stages. A Cel-Ms age of ca. 62 Ma from the subautochthonous Fatric Zobor Nappe (ZI-3 meta-quartzite sample) indicates advanced (late-D3) exhumation of the D1 wedge rear.  The average metamorphic conditions determined from the lower Infratatric Humienec and Jašter thrust sheets C.R. type marly slates with newly formed Ilt-Ph are ca. 220-270 °C and 600-750 MPa by the Chl-Ph geothermobarometry and Ph geobarometry. These conditions are related to the compressional D3 stage or burial of the C.R. underneath the exhumed (D2) higher Infratatric nappes at ca. 75-65 Ma. The newly formed Ilt to Ilt-Ph in the "flysch" pelagites indicates the lowest anchi-metamorphic conditions of the D4 stage.  The lower Infratatric Humienec and Jašter thrust sheets with the C.R. slates, incorporating the rugged thinned basement (micaschists or granitoids with the cover rocks), underlie the higher Infratatric Inovec and Hlohovec nappes after the D3 stage. The Belice "flysch" trough closure at 65-50 Ma was followed by the Infratatricum accretion to the Tatricum and the rear bivergently structured subautochthonous Fatricum in the Eocene orogenic wedge.

Supplementary Materials:
The following are available online at www.mdpi.com/article/10.3390/min11090988/s1. Table S1: Bulk-rock composition of PI-B3, HEL-1-1 and TR-35 in oxide weight percentages.  Table S5: Representative analyses of chlorites and white micas from the Tribeč Mts. Zobor Nappe. Table S6: Representative analyses of chlorites and white micas of the Tribeč Mts. Razdiel Nappe. Table S7: Representative analyses of chlorites and white micas from the Fatricum basement and cover rocks in the eastern Nízke Tatry Mts. Vápenica Nappe. Table S8: Representative analyses of chlorites and white micas from subautochthonous southern Fatricum Krakľová Nappe in the eastern Nízke Tatry Mts.