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-grabe ...
s manifested as numerous individual
graben
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults.
Etymology
''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic contex ...
s located chiefly in the
White Sea
The White Sea (russian: Белое море, ''Béloye móre''; Karelian and fi, Vienanmeri, lit. Dvina Sea; yrk, Сэрако ямʼ, ''Serako yam'') is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is su ...
but including onshore areas and a strip of the
Barents Sea
The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian territo ...
. 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 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. Over geological time the platfor ...
. The system or complex originated due to
extensional tectonics
Extensional tectonics is concerned with the structures formed by, and the tectonic processes associated with, the stretching of a planetary body's crust or lithosphere.
Deformation styles
The types of structure and the geometries formed depend on ...
acting during the Middle to
Late Riphean in 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 ...
. 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
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...
. In the Late
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 ...
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 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
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