Most of Slovakia is situated within the
West Carpathian orogenic belt, except for the east of the country which is in the East Carpathians. However, the geological boundary does not coincide with the geographical one. A large area in the southern part of Slovakia is covered with Miocene sediments of the
Pannonian Basin system. The West Carpathians are Mesozoic to Cenozoic in age. The internal zones were formed on the collapsed
Variscan crust during
Late Paleozoic and
Mesozoic extension.
Outer Western Carpathians The Outer Carpathians form an external
thin-skin thrustbelt around the Inner Carpathian crustal scale
thick-skinned nappes. The two main units are: •
Carpathian Flysch Belt:
Paleogene to
Miocene-age
nappes, made up of folded Cretaceous and Paleogene sedimentary rocks, mostly deep water
turbidites (
flysch). These units are interpreted as a Cretaceous-Miocene
accretionary wedge. The nappes were thrust northward over the
foredeep and the edge of
East European platform. •
Pieniny Klippen Belt: A narrow 10-15 kilometer wide highly compressed zone with relatively rigid Jurassic-Lower Cretaceous limestone "
klippen" surrounded by more plastic Cretaceous
marlstones and
sandstones. Contains rocks of Early Jurassic to Late Cretaceous, locally also Paleogene age. Contains also bodies of
Albian to Late Cretaceous exotic
conglomerates.
Internal Western Carpathians •
Gemericum: the structurally highest thick-skinned crustal scale unit composed of Cambrian or Ordovician through Triassic age
phyllite, metaquartzite,
lydite (black chert) and crystalline limestone partly replaced with
siderite belonging to the
Gelnica and
Rakovec Group. Five to 10 kilometers thick in the
Spišsko-gemerske rudohorie Mountains. Also contains marine rocks from the Carboniferous and Permian volcanic rocks and Permian
granite intrusions. The Gemericum was thrust to the North above the Veporicum unit in mid-Cretaceous. The contact is marked by the
Lubeník-Margecany shear zone. •
Veporicum: middle thick-skinned crustal scale unit formed by Variscan granites and medium- to high-grade metamorphic rocks, mostly gneisses, amphibolites and mica-schists. Also contains Late Paleozoic to Mesozoic sedimentary cover, often with varying degrees of Alpine metamorphism. The contact with the underlying Tatricum is marked by the
Čertovica shear zone. The Veporicum represents the axial zone of West Carpahtian orogen affected by pervasive Alpine metamorphism and exhumation. The complex of Muráň orthogneiss represents one of the oldest rocks in the West Carpathians. •
Tatricum: lower thick-skinned crustal scale unit with similar composition as Veporicum, containing Variscan granites and gneiss, and Mesozoic sedimentary cover. Overlain by the Fatric and Hronic nappes. •
Meliaticum: Represents Jurassic
subduction mélange. Containing Permian gypsum, Triassic limestones and
basalts as well as
serpentinite as blocks in Jurassic claystones and shales. Represents a suture after closure of the
Meliata-Hallstatt ocean. The Melaticum usually occurs in tectonic windows within the Silica Nappe (e.g., at type locality near
Meliata village) and often in hangingwall of Gemericum (e.g., near
Jaklovce village). •
Bôrka Nappe: A narrow belt between Slovak Karst and Gemericum with glaucophanitized, thus affected by HP/LT metamorphism, basic volcanites and other rocks. Most of the protolith formerly belonged to Gemeric rocks. Usually considered as part of Meliaticum. •
Tornaicum: nappe unit in the footwall of Silicium, affected by low pressure metamorphism, containing Triassic metacarbonates of deep water origin. •
Silicicum or Silica Nappe: thin-skinned nappe, with up to 1.2 kilometer thick Triassic
Wetterstein Limestone. The
karst plain of the
Slovak Karst are formed within the Silica Nappe. It did originally include Jurassic rocks, but these have mostly eroded away. The nappe was emplaced in Late Jurassic or earliest Cretaceous. Represents structurally highest nappe unit of the West Carpathians. •
Hronicum or Choč Nappe: thin-skinned nappe system composed of Carboniferous to Lower Cretaceous rocks, mostly limestones (e.g., Wetterstein and
Reifling limestones) and dolomites (
Ramsau and
Wetterstein), locally also thick shales and sandstones of
Lunz Formation. Also includes thick Late Paleozoic volcano-sedimentary
Ipoltica Group. Represents structurally highest nappe above the Tatricum, usually overlying Fatricum. Locally overlain by the Upper Cretaceous
Gosau type basins (e.g.
Brezová Group). •
Fatricum or Krížna Nappe: thin-skinned nappe composed of typical sequence of Triassic to Cretaceous limestones, dolomites, shales (e.g.,
Carpathian Keuper), marlstones (e.g.,
Allgäu Formation), radiolarites (
Ždiar Formation) and sandstones is thrust over the Tatricum in Albian-Turonian. •
Transdanubicum: Mesozoic nappe unit of Austroalpine affinity occurring in the basement of the Danube Basin south of the
Raaba-Hurbanovo-Diosjenő fault zone. •
Zemplinicum: tectonic unit composed of Paleozoic basement and Upper Paleozoic to Mesozoic cover of uncertain tectonic affinity emerging from the basement of the
East Slovak Basin in the
Zemplín Mountains. Important nappe stacking of the Internal Western Carpathians occurred gradually since the early Cretaceous. With peak metamorphism in the core of the internal zones of the orogen at approx. 120 - 80 million years ago. Another
marine transgression flooded the region from the vicinity of the Flysch Belt into the area of the Internal West Carpathians during the middle
Eocene represented by the Sub-Tatra (or Podtatranská) Group or the
Central Carpathian Paleogene Basin. Paleogene sediments are found in the Orava, Liptov, Spiš, Žilina and Podhale depressions. Conglomerates are common as the bottom of the succession, overlain by
flysch (alternating sandstones and claystones). At the edge of the
subducting Flysch Belt, sedimentary rocks are up to four kilometers thick. The Central Carpathian Paleogene Basin rocks are usually not folded, however, local backthrusting was documented.
Molasse deposits laid down in the
Oligocene span into southern Slovakia from the
Pannonian Basin in Hungary. The
back-arc molasse formed several large basins, including the
Vienna Basin,
Danube Basin,
South Slovak Basin and
East Slovak Basin in the
Neogene (the Danube, South Slovak and East Slovak are all subdivisions of the larger
Pannonian Basin). The basins are filled with the sediments associated with the
Paratethys Ocean, up to five kilometers thick. Shales and marls are particularly common, intercalated with sandstone, tuff, conglomerate and algal limestones. Sediments became brackish over time as the Paratethys was isolated from the rest of the world's oceans since Sarmatian to Panonian. Overall, the basins are split up by numerous faults and small grabens, such as the
Trenčín,
Ilava,
Horná Nitra Basin,
Turiec Basin,
Žiar Basin and
Orava Basin, often filled with lake sediments. Geophysical research and boreholes have shed light also on the buried volcanic rocks in the Danube Basin. The buried centers were at Šurany or Kráľová. The volcanic rocks are found throughout the Central Western Carpathians and eastern Slovakia. The volcanism was related to the subduction of the Flysch Belt and back-arc extension of the Pannonian Basin. It is represented by
andesite,
dacite and
rhyolite. Intrusion of granodiorite is known in the area of
Hodruša and
Banská Štiavnica. Youngest late Miocene/Pliocene to Quaternary volcanic activity was represented by alkaline
basalts to
basanites. A swarm of
andesite dikes is also documented in the Pieniny Klippen Belt, however, the Cenozoic volcanic activity in this region was negligible compared to the Central and Eastern Slovakia volcanic field. In the
Upper Pliocene, prior to the Quaternary glaciations Slovakia had a
subtropical climate akin to
Mediterranean climate.
Quaternary The
Quaternary glaciations identified in Slovakia are, from oldest to youngest:
Donau,
Günz,
Mindel,
Riss and
Würm. During these glaciations glaciers extender downhill from the
High Tatras and nonglaciated uplands were subject to
frost weathering and
solifluction.
Deflation of soils is also evident in mountainous locations. Peat, eolian wind-blown sands, fluvial sand and gravel and
loess are all typical
Quaternary sediments, formed in the past 2.5 million years old and dominating the surface of Slovak lowlands. The
loess sheets of Slovakia are named, from the lowest to the highest W1, W2 and W3. In between W1 and W2 lies a layer of
black-earth soil and between W2 and W3 lies an incipient soil which in parts is
gleyed or
cryoturbated. The
Váh River has up to seven terraces of sand and gravel.
Travertine and
tufa is also common, including travertine which preserved a cranial mold of a
Neanderthal from Gánovce.
Moraine formations remain in the high mountains from the
Pleistocene glaciations. ==Economic geology==