Late Carboniferous to Triassic reactivation of Variscan basement in the western English Channel; evidence from onshore exposures in South Cornwall

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doi: 10.1144/gsjgs.154.1.0163
Authors:Shail, Robin K.; Alexander, Andrew C.
Author Affiliations:Primary:
University of Exeter, Camborne School of Mines, Redruth, United Kingdom
Other:
University of Durham, United Kingdom
Volume Title:role of basement reactivation in continental deformation
Volume Authors:Butler, R. W. H., editor; Holdsworth, R. E.; Lloyd, G. E.
Source:Journal of the Geological Society of London, Vol.154 (Part 1), p.163-168; Discussion meeting on The role of basement reactivation in continental deformation, Burlington House, United Kingdom, March 6-7, 1996, edited by R. W. H. Butler, R. E. Holdsworth and G. E. Lloyd. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1997
Note:In English. 26 refs.; illus., incl. sketch maps
Summary:S Cornwall represents the westernmost part of the Variscan basement massif in SW England. Field-based investigations of the distribution, geometry, kinematics and relative chronology of post-Variscan deformation in this area, accompanied by preliminary stress analyses, indicate three episodes of basement reactivation. These are: 1) Stephanian to early Permian NNW-SSE extension, 2) early to late Permian strike-slip deformation and 3) late Permian to Triassic ENE-WSW extension. The data have been used to test and refine previously published models, based on seismic and well-data, of late Carboniferous to Triassic basement reactivation and sedimentary basin development within the Western Approaches Trough. It is confirmed that NNW-SSE regional extension and reactivation of ENE-striking Variscan thrusts had been initiated before the latest Carboniferous, and that ENE-WSW regional extension and dip-slip reactivation of NNW-striking high-angle faults occurred during the Triassic. The Permian strike-slip deformation recognized onshore may have contributed to the development of widespread unconformities within the offshore basins. [R.A.H.]
Subjects:Basement; Basement tectonics; Carboniferous; Deformation; Extension tectonics; Faults; Mesozoic; Orogeny; Paleozoic; Reactivation; Tectonics; Triassic; Upper Carboniferous; Variscan Orogeny; Atlantic Ocean; Cornwall England; England; English Channel; Europe; Great Britain; North Atlantic; United Kingdom; Western Europe
Abstract Numbers:97M/3016
Record ID:1997056642
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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100 1 |a Shail, Robin K.  |e analytic author  |u University of Exeter, Camborne School of Mines, Redruth 
245 1 0 |a Late Carboniferous to Triassic reactivation of Variscan basement in the western English Channel; evidence from onshore exposures in South Cornwall 
300 |a p. 163-168 
500 |a In English. 26 refs. 
500 |a Abstract number: 97M/3016 
500 |a Abstractor: R.A.H. 
500 |a Affiliation: University of Exeter, Camborne School of Mines; Redruth; GBR; United Kingdom 
500 |a Affiliation: University of Durham; ; GBR; United Kingdom 
500 |a Key title: Journal of the Geological Society of London 
500 |a Source note: Journal of the Geological Society of London, Vol.154 (Part 1), p.163-168; Discussion meeting on The role of basement reactivation in continental deformation, Burlington House, United Kingdom, March 6-7, 1996, edited by R. W. H. Butler, R. E. Holdsworth and G. E. Lloyd. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649 
500 |a Publication type: conference paper or compendium article 
504 |b 26 refs. 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom 
520 |a S Cornwall represents the westernmost part of the Variscan basement massif in SW England. Field-based investigations of the distribution, geometry, kinematics and relative chronology of post-Variscan deformation in this area, accompanied by preliminary stress analyses, indicate three episodes of basement reactivation. These are: 1) Stephanian to early Permian NNW-SSE extension, 2) early to late Permian strike-slip deformation and 3) late Permian to Triassic ENE-WSW extension. The data have been used to test and refine previously published models, based on seismic and well-data, of late Carboniferous to Triassic basement reactivation and sedimentary basin development within the Western Approaches Trough. It is confirmed that NNW-SSE regional extension and reactivation of ENE-striking Variscan thrusts had been initiated before the latest Carboniferous, and that ENE-WSW regional extension and dip-slip reactivation of NNW-striking high-angle faults occurred during the Triassic. The Permian strike-slip deformation recognized onshore may have contributed to the development of widespread unconformities within the offshore basins. 
650 7 |a Basement  |2 georeft 
650 7 |a Basement tectonics  |2 georeft 
650 7 |a Carboniferous  |2 georeft 
650 7 |a Deformation  |2 georeft 
650 7 |a Extension tectonics  |2 georeft 
650 7 |a Faults  |2 georeft 
650 7 |a Mesozoic  |2 georeft 
650 7 |a Orogeny  |2 georeft 
650 7 |a Paleozoic  |2 georeft 
650 7 |a Reactivation  |2 georeft 
650 7 |a Tectonics  |2 georeft 
650 7 |a Triassic  |2 georeft 
650 7 |a Upper Carboniferous  |2 georeft 
650 7 |a Variscan Orogeny  |2 georeft 
651 7 |a Atlantic Ocean  |2 georeft 
651 7 |a Cornwall England  |2 georeft 
651 7 |a England  |2 georeft 
651 7 |a English Channel  |2 georeft 
651 7 |a Europe  |2 georeft 
651 7 |a Great Britain  |2 georeft 
651 7 |a North Atlantic  |2 georeft 
651 7 |a United Kingdom  |2 georeft 
651 7 |a Western Europe  |2 georeft 
700 1 |a Alexander, Andrew C.,  |e analytic author 
700 1 |a Holdsworth, R. E.,  |e monographic editor 
700 1 |a Lloyd, G. E.,  |e monographic editor 
711 2 |a Discussion meeting on The role of basement reactivation in continental deformation  |d (1996 :  |c Burlington House, United Kingdom)  
773 0 |a Butler, R. W. H., editor  |t role of basement reactivation in continental deformation  |d London : Geological Society of London, Jan. 1997  |k Journal of the Geological Society of London  |x 0016-7649  |y JGSLAS  |n Journal of the Geological Society of London, Vol.154 (Part 1), p.163-168; Discussion meeting on The role of basement reactivation in continental deformation, Burlington House, United Kingdom, March 6-7, 1996, edited by R. W. H. Butler, R. E. Holdsworth and G. E. Lloyd. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649 Publication type: conference paper or compendium article  |g Vol. 154 , Part 1  |h illus., incl. sketch maps 
856 |u urn:doi: 10.1144/gsjgs.154.1.0163