The geology of

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

is the regional study of rocks, minerals, tectonics, natural resources and groundwater in the country. The oldest rocks in the region are part of the Ukrainian Shield and formed more than 2.5 billion years ago in the

Archean The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic. The Earth Earth ...

eon of the

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...

. Extensive tectonic evolution and numerous

orogeny Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

mountain building events fractured the crust into numerous block, horsts, grabens and depressions and Ukraine was intermittently flooded as the crust downwarped during much of the

Paleozoic The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ' ...

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

and early

Cenozoic The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...

, before the formation of the Alps and Carpathians defined much of its current topography and tectonics. Ukraine was impacted by the Pleistocene glaciations within the last several hundred thousand years. The country has numerous metal deposits as well as minerals, building stone and high-quality industrial sands.

Stratigraphy, tectonics & geologic history

In the Early Archean, the oldest granite layer that now form the

crystalline basement rock of Ukraine began to form. These rocks, including

plagioclase Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more prope ...

granite,

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

and

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

, was reworked into

granulite Granulites are a class of high-grade metamorphic rocks of the granulite facies that have experienced high-temperature and moderate-pressure metamorphism. They are medium to coarse–grained and mainly composed of feldspars sometimes associated w ...

belts due to tectonic evolution in the Archean. The Late Archean was marked by the deposition of ancient

greywacke Greywacke or graywacke (German ''grauwacke'', signifying a grey, earthy rock) is a variety of sandstone generally characterized by its hardness, dark color, and poorly sorted angular grains of quartz, feldspar, and small rock fragments or lit ...

charnockite Charnockite () is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies metamorphic regions, ''sensu stricto'' as an endmember of the charnockite series. Charnockite series The ...

and basic eruptions from numerous volcanoes and fumaroles.

Proterozoic (1.5 billion-539 million years ago)

Tectonic forces had fractured the Archean basement rock into sutures, blocks, troughs and depressions by the start of the

Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...

, although new folding began. The evolution of the rock units in the Proterozoic produced the stable

Ukrainian Shield In geology the Ukrainian Shield (or Ukrainian Crystalline Massif) is the southwest shield of the East European craton. The Ukrainian Shield and the Voronezh Massif consist of 3.2-3.8 Ga Archaean crust in the southwest and east, and 2.3-2.1 Ga ...

, which was broken up further into

horst and graben In geology, horst and graben (or range and valley) refers to topography consisting of alternating raised and lowered fault blocks known as horsts and grabens. The features are created by normal faulting and rifting caused by crustal extensio ...

formations by the Baikalian orogeny. During the Riphean period, a delineation of Eastern European stratigraphy, the

Dnieper-Donets Rift The Dnieper-Donets Rift or Pripyat-Dnieper-Donets Rift (also referred as a "paleorift" and "aulacogen") is an east-west running rift in the Sarmatian Craton that developed and was most active in the Paleozoic. The rift extends from the Caspian Depr ...

began to form.

Paleozoic (539-251 million years ago)

In the

, the Volyn-Podolia region and southern Ukraine subsided and were flooded by a

marine transgression A marine transgression is a geologic event during which sea level rises relative to the land and the shoreline moves toward higher ground, which results in flooding. Transgressions can be caused by the land sinking or by the ocean basins filling ...

, which immersed the region until the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

(or until the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleoz ...

further south). Ukraine experienced volcanic activity related to the

Caledonian orogeny The Caledonian orogeny was a mountain-building era recorded in the northern parts of the British Isles, the Scandinavian Mountains, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occ ...

. The Lvov-Volyn Depression developed in the Volyn-Podolia Platform during the Devonian and

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

. Further tectonic changes came about with the

Hercynian orogeny The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes f ...

, beginning the formation of the Prichernomorian Depression. Basalt and alkaline volcanic rocks intruded the Dnieper-Donets rift zone during this time and the Dnieper-Donets Depression and Donets Basin formed. These

syncline In structural geology, a syncline is a fold with younger layers closer to the center of the structure, whereas an anticline is the inverse of a syncline. A synclinorium (plural synclinoriums or synclinoria) is a large syncline with superimpose ...

structures were flooded by the sea in the

Middle Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wher ...

. In the late Paleozoic, from the Permian into the

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

, dry land continental conditions returned.

Mesozoic (251-66 million years ago)

Much of the Ukrainian Shield was flooded during the Cimmerian orogeny as a large

anticline In structural geology, an anticline is a type of fold that is an arch-like shape and has its oldest beds at its core, whereas a syncline is the inverse of an anticline. A typical anticline is convex up in which the hinge or crest is the ...

formed. The crust downwarped in the Dnieper-Donets Depression and Donets Basin and deeper seas penetrated further inland during the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

. Faults formed as the

Alps The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Sw ...

began to build, together with the

Carpathian Mountains The Carpathian Mountains or Carpathians () are a range of mountains forming an arc across Central Europe. Roughly long, it is the third-longest European mountain range after the Urals at and the Scandinavian Mountains at . The range stretches ...

, separating much of Ukraine from the Precarpathian Foredeep and Transcarpathian Depression. The central Ukrainian Shield was flooded during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

Cenozoic (66 million years ago-present)

In the

an overall uplift of the region led to the retreat of seas to the north, with the exception of a transgression during the

Eocene The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...

. Marine basins finally retreated entirely in the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

. A meganticlinorium had formed in Crimea by the end of the Oligocene. During the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

in the recent geologic past, much of Ukraine was covered with glaciers with the exception of areas around the Sea of Azov and Black Sea which were flooded during the time period.

Natural resource geology

The Proterozoic Ukrainian Shield hosts iron ore deposits in the Krivorozhsky Basin, while iron ore is also found in the Neogene Prichernomorian Depression. Manganese ores are known from Oligocene rocks in the south slope of the Ukrainian shield and titanium is found in magmatic and alluvial deposits. Tungsten, molybdenum, vanadium, nickel, cobalt and chromium occur on the shield as well. Mercury deposits in the Donets Basin are hosted in Carboniferous sandstones as well as in the Transcarpathian Trough and Crimea (lead-zinc-gold mineralization are also found, while copper is found in Permian rocks in the Donets Basin). Geologists have discovered oil and gas deposits in the Neogene of the Precarpathian Foredeep, the Paleozoic of the Dnieper-Donets Depression and in the Oligocene of the Prichernomorian Depression. Large coal reserves are situated in the Dnieper Lignite Basin, Donets Basin and Lvov-Volyn Depression. Additionally, Ukraine has combustible black shale and peat deposits. The construction industry often quarries Precambrian granite from the Ukraine Shield, while chemical industries extract rock salt, talc, mica, feldspar and glass-grade sand.

References

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