Sweden: Lithotectonic Framework, Tectonic Evolution and Mineral Resources
The solid rock mass of Sweden forms a natural field laboratory revealing insight into the westward growth and reworking of one of the planet's ancient continental nuclei. Three major geological units are exposed in different parts of the country: the western part of the Fennoscandian Shield, mainly sedimentary rocks deposited on this crystalline rock mass and the Caledonide orogen. This volume synthesizes the tectonic evolution of Sweden over more than 2500 million years from the Neoarchean to the Neogene. Following an introduction describing the lithotectonic framework of the country and the organization of the volume, the tectonic evolution is addressed essentially chronologically. Different phases of intracratonic rifting, accretionary orogeny, continent–continent collisional orogeny and platformal sedimentation are identified. Sweden is one of Europe's major suppliers of metals, and the country's mineral resources are also presented in the context of the lithotectonic framework. Sweden: Lithotectonic Framework, Tectonic Evolution and Mineral Resources has been designed to interest a professional geoscientific audience and advanced students of Earth Sciences.
Chapter 7: Småland lithotectonic unit dominated by Paleoproterozoic (1.8 Ga) syn-orogenic magmatism, Svecokarelian orogen
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Published:January 03, 2020
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CiteCitation
Carl-Henric Wahlgren, Michael B. Stephens, 2020. "Småland lithotectonic unit dominated by Paleoproterozoic (1.8 Ga) syn-orogenic magmatism, Svecokarelian orogen", Sweden: Lithotectonic Framework, Tectonic Evolution and Mineral Resources, M. B. Stephens, J. Bergman Weihed
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Abstract
The Småland lithotectonic unit in the 2.0−1.8 Ga Svecokarelian orogen, southeastern Sweden, is dominated by a c. 1.81−1.77 Ga alkali–calcic magmatic suite (the Transscandinavian Igneous Belt or TIB-1). At least in its central part, the TIB-1 suite was deposited on, or emplaced into, c. 1.83–1.82 Ga calc-alkaline magmatic rocks with base metal sulphide mineralization and siliciclastic sedimentary rocks (the Oskarshamn–Jönköping Belt). Ductile deformation and metamorphism under low- to medium-grade conditions affected the Oskarshamn–Jönköping Belt prior to c. 1.81 Ga. Both suites were subsequently affected by low-grade ductile deformation, mainly along steeply dipping, east–west to NW–SE shear zones with dip-slip and dextral strike-slip displacement. Sinistral strike-slip NE–SW zones are also present. In the northern part of the lithotectonic unit, 1.9 Ga magmatic rocks, c. 1.87–1.81 Ga siliciclastic sedimentary rocks and basalt, and c. 1.86–1.85 Ga granite show fabric development, folding along steep NW–SE axial surfaces and medium- or high-grade metamorphism prior to c. 1.81 Ga and, at least partly, at c. 1.86–1.85 Ga; base metal sulphide, Fe oxide and U or U–REE mineralizations also occur. Magmatism and siliciclastic sedimentation along an active continental margin associated with subduction-related, accretionary tectonic processes is inferred over about 100 million years.
- Ar/Ar
- deformation
- ductile deformation
- Europe
- faults
- granites
- igneous rocks
- magmatism
- metamorphic rocks
- metamorphism
- mineralization
- nesosilicates
- orogeny
- orthosilicates
- Paleoproterozoic
- plate tectonics
- plutonic rocks
- Precambrian
- Proterozoic
- Scandinavia
- shear zones
- silicates
- Smaland
- Svecofennian Orogeny
- Sweden
- U/Pb
- upper Precambrian
- Western Europe
- zircon
- zircon group