East European craton
Encyclopedia
The East European craton is the core of the Baltica
proto-plate and consists of three crustal regions/segments: Fennoscandia
to the northwest, Volgo-Uralia to the east, and Sarmatia
to the south. Fennoscandia includes the Baltic Shield
(also referred to as the Fennoscandian Shield) and has a diversified accretionary
Archaean and Early Proterozoic
crust
, while Sarmatia has an older Archaean crust. The Volgo-Uralia region has a thick sedimentary cover, however deep drillings have revealed mostly Archaean crust. There are two shields in the East European Craton: the Baltic/Fennoscandian shield and the Ukrainian shield. The Ukrainian Shield
and the Voronezh Massif consists of 3.2-3.8 Ga
Archaean crust in the southwest and east, and 2.3-2.1 Ga Early Proterozoic orogenic belts
.
The Ural Mountains
of central Russia is the eastern margin of the East European craton and marks the Late Paleozoic
orogenic collision of the East European craton with the Siberian craton
s. The southern margin of the craton is where Sarmatia is buried beneath thick Phanerozoic
sediments and the Alpine orogens. The intervening Late Palaeozoic Donbass Fold Belt, also known as part of the Pripyat
-Dniepr-Donets aulacogen
, transects Sarmatia, dividing it into the Ukrainian Shield and the Voronezh Massif. The southwestern boundary is known as the Trans European Suture Zone and separates the East European craton from the Phanerozoic
orogens of Western Europe
. The northwestern margin of the craton is overlaid by the fold-and-thrust Early Paleozoic Caledonian
orogen.
(middle to late Proterozoic) sedimentary cover over its 3000-km-wide platform
area. This is in sharp contrast to the exposed northwest portion of the Baltic Shield
, and the Ukrainian Shield in the southwest. The lithospheric thickness also varies widely from 150–200 km in Ukraine
to 120 km in southern Russia
to over 250 km thick in the NE Baltic Shield, with extremely wide thickness fluctuations of the crustal layers. A shield in any craton
is the area of exposed crystalline crust while the other part of the craton is the “platform
” where the crystalline crust
or basement
is overlaid by younger sedimentary cover. Thus the crustal segments of the East European craton comprise both the Baltic Shield and the Ukrainian shield, and the sedimentary platform basement.
Baltica
Baltica is a name applied by geologists to a late-Proterozoic, early-Palaeozoic continent that now includes the East European craton of northwestern Eurasia. Baltica was created as an entity not earlier than 1.8 billion years ago. Before this time, the three segments/continents that now comprise...
proto-plate and consists of three crustal regions/segments: Fennoscandia
Fennoscandia
Fennoscandia and Fenno-Scandinavia are geographic and geological terms used to describe the Scandinavian Peninsula, the Kola Peninsula, Karelia and Finland...
to the northwest, Volgo-Uralia to the east, and Sarmatia
Sarmatian craton
Sarmatian craton is a geological and tectonics term for the southern segment/region of the East European craton also known as Scythian plateau. The craton contains Archaean rocks 2.8 to 3.7 billion years old. During the Carboniferous Period the craton was rifted apart by the Dneiper Donets rift...
to the south. Fennoscandia includes the Baltic Shield
Baltic Shield
The Baltic Shield is located in Fennoscandia , northwest Russia and under the Baltic Sea. The Baltic Shield is defined as the exposed Precambrian northwest segment of the East European Craton...
(also referred to as the Fennoscandian Shield) and has a diversified accretionary
Accretion (geology)
Accretion is a process by which material is added to a tectonic plate or a landmass. This material may be sediment, volcanic arcs, seamounts or other igneous features.-Description:...
Archaean and Early Proterozoic
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
crust
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
, while Sarmatia has an older Archaean crust. The Volgo-Uralia region has a thick sedimentary cover, however deep drillings have revealed mostly Archaean crust. There are two shields in the East European Craton: the Baltic/Fennoscandian shield and the Ukrainian shield. The Ukrainian Shield
Ukrainian shield
The Ukrainian Shield 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 Early Proterozoic orogenic belts....
and the Voronezh Massif consists of 3.2-3.8 Ga
Gya
In astronomy, geology, and paleontology, Gya or Ga is a year multiplied by one of the SI prefix multipliers. It is often used as a unit of time to denote length of time before the present...
Archaean crust in the southwest and east, and 2.3-2.1 Ga Early Proterozoic orogenic belts
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...
.
The Ural Mountains
Ural Mountains
The Ural Mountains , or simply the Urals, are a mountain range that runs approximately from north to south through western Russia, from the coast of the Arctic Ocean to the Ural River and northwestern Kazakhstan. Their eastern side is usually considered the natural boundary between Europe and Asia...
of central Russia is the eastern margin of the East European craton and marks the Late Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
orogenic collision of the East European craton with the Siberian craton
Siberia (continent)
Siberia is the craton located in the heart of the region of Siberia. Siberia or "Angaraland" is today the Central Siberian Plateau...
s. The southern margin of the craton is where Sarmatia is buried beneath thick Phanerozoic
Phanerozoic
The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 542 million years and goes back to the time when diverse hard-shelled animals first appeared...
sediments and the Alpine orogens. The intervening Late Palaeozoic Donbass Fold Belt, also known as part of the Pripyat
Pripyat River
The Pripyat River or Prypiat River is a river in Eastern Europe, approximately long. It flows east through Ukraine, Belarus, and Ukraine again, draining into the Dnieper....
-Dniepr-Donets aulacogen
Aulacogen
In geology, an aulacogen is a failed arm of a triple junction of a plate tectonics rift system. A triple junction beneath a continental plate initiates a three way breakup of the continental plate. As the continental break-up develops one of the three spreading ridges typically fails or stops...
, transects Sarmatia, dividing it into the Ukrainian Shield and the Voronezh Massif. The southwestern boundary is known as the Trans European Suture Zone and separates the East European craton from the Phanerozoic
Phanerozoic
The Phanerozoic Eon is the current eon in the geologic timescale, and the one during which abundant animal life has existed. It covers roughly 542 million years and goes back to the time when diverse hard-shelled animals first appeared...
orogens of Western Europe
Western Europe
Western Europe is a loose term for the collection of countries in the western most region of the European continents, though this definition is context-dependent and carries cultural and political connotations. One definition describes Western Europe as a geographic entity—the region lying in the...
. The northwestern margin of the craton is overlaid by the fold-and-thrust Early Paleozoic Caledonian
Caledonian
Caledonian is a geographical term used to refer to places, species, or items in or from Scotland, or particularly the Scottish Highlands. It derives from Caledonia, the Roman name for the area of modern Scotland...
orogen.
Platform basement
The most distinguishable physiographic aspect of the East European craton is the extensive 3-km and more-thick RipheanRiphean stage
The Riphean is a stage or age of the geologic timescale from . The name Riphean is used in the Proterozoic stratigraphy of the Siberian Craton in Russia...
(middle to late Proterozoic) sedimentary cover over its 3000-km-wide platform
Platform (geology)
In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation...
area. This is in sharp contrast to the exposed northwest portion of the Baltic Shield
Baltic Shield
The Baltic Shield is located in Fennoscandia , northwest Russia and under the Baltic Sea. The Baltic Shield is defined as the exposed Precambrian northwest segment of the East European Craton...
, and the Ukrainian Shield in the southwest. The lithospheric thickness also varies widely from 150–200 km in Ukraine
Ukraine
Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...
to 120 km in southern Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
to over 250 km thick in the NE Baltic Shield, with extremely wide thickness fluctuations of the crustal layers. A shield in any craton
Craton
A craton is an old and stable part of the continental lithosphere. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by...
is the area of exposed crystalline crust while the other part of the craton is the “platform
Platform (geology)
In geology, a platform is a continental area covered by relatively flat or gently tilted, mainly sedimentary strata, which overlie a basement of consolidated igneous or metamorphic rocks of an earlier deformation...
” where the crystalline crust
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
or basement
Basement (geology)
In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin...
is overlaid by younger sedimentary cover. Thus the crustal segments of the East European craton comprise both the Baltic Shield and the Ukrainian shield, and the sedimentary platform basement.