Northern Europe I

Advanced tectonics
James S. Aber

Tectonic overview

Northern Europe, including the British Isles, Scandinavia and the Baltic region, has a geologic history similar to that of eastern North America throughout much of the Phanerozoic. This is the tectonically stable portion of Europe, which has seen little in the way of crustal deformation since the Paleozoic. Geologic history of the Precambrian and Paleozoic may be summarized as a sequence of orogenies and intervening stable periods.

Proterozoic Geology

Svaneke Granite exposed on the shoreline of northeastern Bornholm, Denmark. The pink-red granite is coarse grained with crystals up to 2 cm in size and has numerous pegmatites and inclusions of mafic rocks.
Snorrebakken granite quarry, Bornholm, Denmark. Crystalline rocks of Bornholm date from the late Proterozoic--Gothide province of the Fennoscandian Shield. It's said that half the streets in old cities of northern Europe were paved with stone from Bornholm.
Granite cliff at Hammer lighthouse, northwestern Bornholm, Denmark. The Hammer Granite is the youngest and lightest in color on Bornholm. This is a typical situation that younger granites are lighter in color (Jørgart 1977).
Middle Proterozoic crystalline rock (gneiss) of the Fennoscandian Shield, Stockholm, Sweden. See closeup view in next image.
Vertical foliation and diagonal fractures in gneiss, Stockholm, Sweden. This example is part of the extensive middle Proterozoic Svecofennide province of the Fennoscandian Shield.
Glacially scoured Proterozoic granite and granodiorite, Kvaløy, near Tromsø, northern Norway.
Proterozoic amphibolite and metagabbro, Sommarøy, near Tromsø, northern Norway.
Precambrian gneiss exposed in vicinity of the glacier, Nigardsbreen, south-central Norway.
Proterozoic gneiss displayed in the Granvin potholes, south-central Norway.

Paleozoic Geology

Quarry in Nexø sandstone, basal Cambrian strata, Bornholm, Denmark. This terrestrial sandstone lacks fossils and was deposited in a floodplain environment directly on the stable basement rocks of southern Scandinavia (Bruun-Petersen 1977).
The so-called "Orthoceratite limestone" (lower Ordovician) in a small quarry on Bornholm, Denmark. The limestone was deposited in relatively shallow water during a marine transgression of the Baltic region.

Map of bedrock geology of Estonia, eastern Baltic region. The northern portion is underlain mainly by Ordovician limestones (green); Devonian sandstone (brown) is found in the southern portion--see next three photos. The Paleozoic strata rest on crystalline basement and dip gently to the south.

Ordovician limestone on the island of Vormsi, northwestern Estonia. Bedrock occurs at sea level, and the beach is composed of limestone gravel (see next image).
Closeup view of limestone bedrock strand flat with a scattering of glacial erratics, Vormsi, Estonia. Ordovician limestone is found across the central Baltic region, especially on Swedish islands and in Estonia.
Cliff and caves in Devonian sandstone on the shore of Lake Peipsi, eastern Estonia. The sandstone is poorly consolidated and erodes easily. It is an eastern representative of the Old Red Continent.
Tunnel boring machine drilling into granitic gneiss. This Precambrian gneiss was reworked during the Caledonian Orogeny (Devonian). Bergen, western Norway.
Anorthosite section near Indre Arna, vicinity of Bergen, western Norway. Anorthosite is typical of the Grenvillian Orogeny (late Proterozoic), and this rock was reworked during the Caledonian Orogeny (Devonian).
Greenstone (soapstone) architecture at Lyse Kloster, a medieval cloister south of Bergen, western Norway. Caledonian metamorphic rock from the Bergen structural arch.
Phyllite bedrock exposed on the shore at Clogga, south of Dublin, Ireland. This rock was deformed during the Caledonian Orogeny (Devonian).
Glaciated highlands are supported by massive Devonian sandstone, Molls Gap, southwestern Ireland. Thick sandstones resulted from rapid erosion of the Caledonian mountains and sediment accumulation in adjacent basins.
Metamorphic strata exposed in the strand flat at Wembury Bay, southwestern England, United Kingdom. These Devonian strata were deformed during the Variscan Orogeny (Carboniferous).
Granite quarry in Dartmoor, southwestern England, United Kingdom. This region was subjected to the Variscan Orogeny during the Carboniferous.
Red, black, and gray sandstone and shale tilted up in a vertical position, south coast of Ireland. These Devonian strata were deformed during the Variscan Orogeny in the Carboniferous.
Permian dike (red) cuts through Cambro-Ordovician shale and limestone, Oslo Fjord, Norway. Rhyolitic intrusions mark reactivation of the Oslo Graben during the Permian.
Permian dike (red) branches into Cambro-Ordovician shale and limestone, Oslo Fjord, Norway. These intrusions are evidence for crustal tension associated with rifting of the Oslo Graben.

References

Northern Europe II.

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Notice: Advanced tectonics is presented for the use and benefit of students enrolled at Emporia State University. Others are welcome to view the course webpages. Any other use of text, imagery or curriculum materials is prohibited without permission of the instructor. All text and images © J.S. Aber (2014).