The White Sea Rift System is a complex of

rift In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben ...

s manifested as numerous individual

graben In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 't ...

s located chiefly in the

White Sea The White Sea (; Karelian language, Karelian and ; ) is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is surrounded by Karelia to the west, the Kola Peninsula to the north, and the Kanin Peninsula to the nort ...

but including onshore areas and a strip of the

Barents Sea The Barents Sea ( , also ; , ; ) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territorial waters.World Wildlife Fund, 2008. It was known earlier among Russi ...

. The rifts run in a subparallel manner from northwest to southeast where the rift system continues under the

East European Platform East European Platform or Russian Platform is a large and flat area of the East European Craton covered by sediments in Eastern Europe spanning from the Ural Mountains to the Tornquist Zone and from the Peri-Caspian Basin to the Barents Sea. O ...

. The system or complex originated due to

extensional tectonics Extensional tectonics is concerned with the structures formed by, and the Tectonics, tectonic processes associated with, the stretching of a planetary body's Crust (geology), crust or lithosphere. Deformation styles The types of structure and the ...

acting during the Middle to Late Riphean in the

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

. This tectonic environment is believed to have been related to the break-up of the ancient

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continent, continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", ...

Palaeopangea. During the Riphean the graben structures were filled by Jotnian sediments. During the Middle Paleozoic the rift system was reactivated resulting in

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

of alkaline magmas. In the Late

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

the rift system was reactivated again resulting in the formation of the modern White Sea. The White Sea Rift System includes the following rifts: *the Onega–Kandalaksha Rift (its northwestern graben is known as the Kandalaksha Trough or Kandalaksha Graben). The Kandalksha graben is about 220 km long and 60 km broad. Its southwestern slopes are steeper than its northwestern slopes. *the Kerets–Leshukonsky Rift (including the Kerets Graben). *the Barents Rift. Many of the grabens are filled with Jotnian sediments.

Notes

References

Geology of European Russia Mesoproterozoic Mesoproterozoic rifts and grabens {{Russia-geo-stub