|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| Journal of the Geological Society |  |
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Article |
1 Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
2 Department of Geology, University College, Cardiff, Cardiff CF1 1XL, UK
The Welsh Borderland Fault System forms one of the most prominent tectonic lines in Southern Britain and, along with the Menai Straits and Malverns Fault Systems, is a candidate for a terrane boundry. A review of stratigraphic linkage across the system reveals significant contrasts in pre-Ashgill sequences. These contrasts occur particularly across its north-west edge, the Pontesford and Tywi Lineaments, rather than across the Church Stretton Lineament. The Ashgill event produced strike-slip dominated structure and an unconformity that expands from the Welsh Basin towards the platform. An important linkage sequence was produced by the subsequent late Ashgill to Llandovery marine transgression across the fault system. Silurian facies changes are marked but gradational, and no more than expected across a basin margin from stable to thinned crust.
Devonian (Acadian) sinistral transpression, and later Phanerozoic movements, reactivated the fault system but did not engineer major terrane amalgamation across it. This reactivation has obscured the early history of the fault system. The remaining evidence admits, though does not prove, major Ashgill or earlier transcurrent movements. Broader considerations suggest that the Welsh Borderland Fault System originated either as a Cambro-Ordovician extensional system on the south-eastern margin of the Welsh Basin or during Late Precambrian-Early Cambrian transcurrent movements occurring within Avalonia, inboard from the Menai Strait line.
This article has been cited by other articles:
|
|
 |
|
  T. R. A. VANDENBROUCKE, A. ANCILLETTA, R. A. FORTEY, and J. VERNIERS A modern assessment of Ordovician chitinozoans from the Shelve and Caradoc areas, Shropshire, and their significance for correlation Geological Magazine, March 1, 2009; 146(2): 216 - 236. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Verniers, T. Pharaoh, L. Andre, T.N. Debacker, W. De Vos, M. Everaerts, A. Herbosch, J. Samuellson, M. Sintubin, and M. Vecoli The Cambrian to mid Devonian basin development and deformation history of Eastern Avalonia, east of the Midlands Microcraton: new data and a review Geological Society, London, Special Publications, January 1, 2002; 201(1): 47 - 93. [Abstract] [PDF]
|
|
|
|
|
|
P. F. Friend, B. P. J. Williams, M. Ford, and E. A. Williams Kinematics and dynamics of Old Red Sandstone basins Geological Society, London, Special Publications, January 1, 2000; 180(1): 29 - 60. [Abstract] [PDF]
|
|
|
|
|
|
R. D. Hillier Silurian marginal marine sedimentation and the anatomy of the marine-Old Red Sandstone transition in Pembrokeshire, SW Wales Geological Society, London, Special Publications, January 1, 2000; 180(1): 343 - 354. [Abstract] [PDF]
|
|
|
|
|
|
G. Owen and D. Hawley Depositional setting of the Lower Old Red Sandstone at Pantymaes Quarry, central South Wales: new perspectives on the significance and occurrence of 'Senni Beds' facies Geological Society, London, Special Publications, January 1, 2000; 180(1): 389 - 400. [Abstract] [PDF]
|
|
|
|
|
|
G. S. Kimbell and D. G. Quirk Crustal magnetic structure of the Irish Sea region: evidence for a major basement boundary beneath the Isle of Man Geological Society, London, Special Publications, January 1, 1999; 160(1): 227 - 238. [Abstract] [PDF]
|
|
|
|
 |
|
 A. J. Butler, A. J. BUTLER, N. H. WOODCOCK, and D. M. STEWART The Woolhope and Usk Basins: Silurian rift basins revealed by subsurface mapping of the southern Welsh Borderland Journal of the Geological Society, January 1, 1997; 154(2): 209 - 223. [Abstract] [PDF]
|
|
|
|
 |
|
 D. B. Thompson and J. A. Winchester Field relationships, geochemistry, and tectonic context of the Tertiary dyke suites in Staffordshire and Shropshire, central England Proceedings of the Yorkshire Geological Society, June 1, 1995; 50(3): 191 - 208. [Abstract] [PDF]
|
|
|
|
|
|
J. H. McD. WHITAKER Silurian basin slope sedimentation and mass movement in the Wigmore Rolls area, central Welsh Borderland Journal of the Geological Society, February 1, 1994; 151(1): 27 - 40. [Abstract] [PDF]
|
|
|
|
 |
|
 B. J. Bluck, W. Gibbons, and J. K. Ingham Terranes Geological Society, London, Memoirs, January 1, 1992; 13(1): 1 - 4. [Abstract] [PDF]
|
|
|
|
|
|
R. D. TUCKER and T. C. PHARAOH U-Pb zircon ages for Late Precambrian igneous rocks in southern Britain Journal of the Geological Society, June 1, 1991; 148(3): 435 - 443. [Abstract] [PDF]
|
|
|
|
|
|
N. H. WOODCOCK Sequence stratigraphy of the Palaeozoic Welsh Basin Journal of the Geological Society, June 1, 1990; 147(3): 537 - 547. [Abstract] [PDF]
|
|
|
|
|
|
W. Gibbons and J. Horak Contrasting metamorphic terranes in northwest Wales Geological Society, London, Special Publications, January 1, 1990; 51(1): 315 - 327. [Abstract] [PDF]
|
|
|
|
|
|
J. C. Pauley Sedimentology, structural evolution and tectonic setting of the late Precambrian Longmyndian Supergroup of the Welsh Borderland, UK Geological Society, London, Special Publications, January 1, 1990; 51(1): 341 - 351. [Abstract] [PDF]
|
|
|
|
|
|
W. Gibbons Transcurrent ductile shear zones and the dispersal of the Avalon superterrane Geological Society, London, Special Publications, January 1, 1990; 51(1): 407 - 423. [Abstract] [PDF]
|
|
|
|
|
|
N. H. WOODCOCK Strike-slip faulting along the Church Stretton Lineament, Old Radnor Inlier, Wales Journal of the Geological Society, December 1, 1988; 145(6): 925 - 933. [Abstract] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
