Geology of Sweden

Complex orogeny mountain building events and other tectonic occurrences built up extensive metamorphic crystalline basement rock that often contains valuable metal deposits throughout much of the country.

Northern Sweden has greenstone belts made up of mafic volcanic rocks with intercalations of komatiite, quartzite, graphite schist and Lapponian marble.

The Svecokarelian Orogeny between 1.95 and 1.85 billion years ago deposited the metavolcanic and metasedimentary Svecofennian-Kalevian rocks, along with calc-alkaline granitoid intrusions.

South of the Skellefte district in north-central Sweden, in the Bothnian Basin, metagrayacke interlayers with metavolcanic rocks and metamorphosed under high pressure to paragneiss and migmatite.

Swarms of mafic dikes are dated to 1.56-1.5, 1.25-1.2 and one billion to 900 million years ago, striking north-northwest in the western part of the Svecokarelian orogen.

Granite, syenite and mafic intrusions are distributed throughout the broader grouping of Sveconorwegian rocks, which intruded before the Gothian event, but before extensive deformation took place.

Aside from a skarn iron oxide and manganese deposit at Langban and some copper, lead and zinc mineralization, the Sveconorwegian rocks tend to be poor in metal resources.

The Swedish Caledonides formed due to an orogeny in the early Paleozoic, along the western margin of Sweden approximately 510 to 400 million years ago.

The complex tectonic evolution of the Caledonides built up lead-zinc sulfides from the Neoproterozoic to the Cambrian in quartz arenite, along with subsequent, more widely distributed zinc, copper, gold and lead deposits.

During the Silurian, Balitca was situated on the equator and the subduction of oceanic crust had closed the gap with Laurentia (proto-North America), beginning the formation of the new supercontinent Pangaea.

Early Paleozoic rocks in this area are up to one kilometer thick, continuing upward into Mesozoic and Cenozoic shale, siltstone and sandstone.

The Skellefte district is known for a massive sulfide deposit hosted in metavolcanic rocks, together with gold mineralization in quartz veins.

Non-metallic resources include Paleozoic limestone extracted on Gotland in the 1100s through the 1500s for use in city walls and house throughout the Hanseatic League.

Geological map of Fennoscandia .
Archean rocks of the Karelia, Belomorian and Kola domains
Proterozoic rocks of the Karelia and Kola domains
Svecofennian Domain
Transscandinavian Igneous Belt
Timanide Orogen
Sveconorwegian Orogen inc. the Western Gneiss Region
Caledonian nappes
Granite, in Smögen (southwestern Sweden), formed during the Sveconorwegian orogeny
Tjakkeli, a mountain in Norrbotten County (northern Sweden), is made of mylonitised syenitoid -granitic igneous rock above quartz arenite sedimentary rock (about 1,880 to 490 million years old), originally formed in another location and transported eastward during the Caledonian orogeny , about 450 million years ago, as part of a large nappe fold, thrust on top of the underlying Svecokarelian basement (about 1,920 to 1,870 million years old) [ 4 ] [ 5 ] [ 6 ]
Iron ore ( hematite and magnetite ) from Gällivare
Map of natural resources - metals are in blue ( Fe , Cu , Zn , As (semi-metal), Ag , W , Au , Pb , U ; PY — pyrite ), fossil fuels are in red (C — coal , OS — oil shale )