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Reconstructing the tectonic history of Fennoscandia from its margins: The past 100 million years

Abstract

In the absence of onland late Mesozoic and Cenozoic geological formations the tectonic history of the Baltic Shield over the past 100 million years can be reconstructed from the thick sedimentary basins that surround Fennoscandia on three sides. Tectonic activity around Fennoscandia through this period has been diverse but can be divided into four main periods: a. pre North Atlantic spreading ridge (100-60 Ma) when transpressional deformation on the southern margins of Fennoscandia and transtensional activity to the west was associated with a NNE-SSW maximum compressive stress direction; b. the creation of the spreading ridge (60-45 Ma) when there was rifting along the western margin; c. the re-arrangement of spreading axes (45-25 Ma) when there was a radial compression around Fennoscandia, and d. the re-emergence of the Iceland hot-spot (25-0 Ma) when the stress-field has come to accord with ridge or plume `push`. Since 60 Ma the Alpine plate boundary has had little influence on Fennoscandia. The highest levels of deformation on the margins of Fennoscandia were achieved around 85 Ma, 60-55 Ma, with strain-rates around 10{sup -9}/year. Within the Baltic Shield long term strain rates have been around 10{sup -1}1/year, with little evidence for significant deformations passing into the  More>>
Authors:
Muir Wood, R [1] 
  1. EQE International Ltd (United Kingdom)
Publication Date:
Dec 01, 1995
Product Type:
Technical Report
Report Number:
SKB-TR-95-36
Reference Number:
SCA: 540250; 052002; PA: AIX-28:017559; EDB-97:029182; NTS-97:007370; SN: 97001735523
Resource Relation:
Other Information: PBD: Dec 1995
Subject:
54 ENVIRONMENTAL SCIENCES; 05 NUCLEAR FUELS; SCANDINAVIA; TECTONICS; BASEMENT ROCK; GEOLOGIC STRUCTURES; SEISMICITY; STRESS ANALYSIS; UNDERGROUND DISPOSAL
OSTI ID:
432431
Research Organizations:
Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Journal ID: ISSN 0284-3757; Other: ON: DE97614021; TRN: SE9700003017559
Availability:
INIS; OSTI as DE97614021
Submitting Site:
SWDN
Size:
123 p.
Announcement Date:
Feb 27, 1997

Citation Formats

Muir Wood, R. Reconstructing the tectonic history of Fennoscandia from its margins: The past 100 million years. Sweden: N. p., 1995. Web.
Muir Wood, R. Reconstructing the tectonic history of Fennoscandia from its margins: The past 100 million years. Sweden.
Muir Wood, R. 1995. "Reconstructing the tectonic history of Fennoscandia from its margins: The past 100 million years." Sweden.
@misc{etde_432431,
title = {Reconstructing the tectonic history of Fennoscandia from its margins: The past 100 million years}
author = {Muir Wood, R}
abstractNote = {In the absence of onland late Mesozoic and Cenozoic geological formations the tectonic history of the Baltic Shield over the past 100 million years can be reconstructed from the thick sedimentary basins that surround Fennoscandia on three sides. Tectonic activity around Fennoscandia through this period has been diverse but can be divided into four main periods: a. pre North Atlantic spreading ridge (100-60 Ma) when transpressional deformation on the southern margins of Fennoscandia and transtensional activity to the west was associated with a NNE-SSW maximum compressive stress direction; b. the creation of the spreading ridge (60-45 Ma) when there was rifting along the western margin; c. the re-arrangement of spreading axes (45-25 Ma) when there was a radial compression around Fennoscandia, and d. the re-emergence of the Iceland hot-spot (25-0 Ma) when the stress-field has come to accord with ridge or plume `push`. Since 60 Ma the Alpine plate boundary has had little influence on Fennoscandia. The highest levels of deformation on the margins of Fennoscandia were achieved around 85 Ma, 60-55 Ma, with strain-rates around 10{sup -9}/year. Within the Baltic Shield long term strain rates have been around 10{sup -1}1/year, with little evidence for significant deformations passing into the shield from the margins. Fennoscandian Border Zone activity, which was prominent from 90-60 Ma, was largely abandoned following the creation of the Norwegian Sea spreading ridge, and with the exception of the Lofoten margin, there is subsequently little evidence for deformation passing into Fennoscandia. Renewal of modest compressional deformation in the Voering Basin suggest that the `Current Tectonic Regime` is of Quaternary age although the orientation of the major stress axis has remained consistent since around 10 Ma. The past pattern of changes suggest that in the geological near-future variations are to be anticipated in the magnitude rather than the orientation of stresses.}
place = {Sweden}
year = {1995}
month = {Dec}
}