|
Article |
1 Department of Geology, University of Western Australia, Nedlands, Perth, WA 6009, Australia
2 Geological Survey of Norway, PB 3006 Lade, N–7002 Trondheim, Norway
Early Wenlock volcanic rocks from the East Mendips inlier, SW England, yield primary palaeomagnetic directions which indicate that southern Britain (Eastern Avalonia) occupied a palaeolatitude of 13 ± 5°S in Mid-Silurian (430 Ma) times.
When combined with coeval data from Laurentia, the southern Laurentian margin (Scottish terranes), and Baltica, the collective data indicate that: (1) the British and Scandinavian sectors of the Iapetus Ocean were closed, to within the limits of the palaeomagnetic resolution, by the Early Wenlock; (2) Acadian deformation across Britain, which culminated in Early Devonian time, post-dated initial docking of Eastern Avalonia and Laurentia; (3) a previous palaeomagnetic requirement for the Tornquist Sea to remain open into Mid-Silurian times is removed, thereby reconciling palaeomagnetic and biogeographical constraints upon the convergence of southern Britain and Baltica.
Recently-acquired palaeomagnetic data from southern Britain and Baltica have facilitated more reliable reconstructions of the early Palaeozoic palaeogeography of Northern Europe (Fig. 1). Palaeomagnetic data now record the progressive drift of southern Britain across the Iapetus Ocean during Ordovician times (Torsvik & Trench 1991; Channell et al. 1992) and a predominant northward drift and counterclockwise rotation of Baltica from Cambrian to Devonian times (Torsvik et al. 1991aTorsvik et al. 1992a; Perroud et al. 1992). Nevertheless, details on the closure history of the Iapetus Ocean and Tornquist Sea (Fig. 1) have remained sketchy due to a sparseness of coeval Late Ordovician–Mid-Silurian data from the bordering continents. These palaeomagnetic uncertainties permit competing geological models.
In this contribution, we address two outstanding problems relating to the closure
This article has been cited by other articles:
 |
|
 |
|
  C. R. CONGREVE and B. S. LIEBERMAN PHYLOGENETIC AND BIOGEOGRAPHIC ANALYSIS OF DEIPHONINE TRILOBITES Journal of Paleontology, 2010; 84: 128 - 136. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. E. BROWN, P. D. RYAN, N. J. SOPER, and N. H. WOODCOCK The Newer Granite problem revisited: a transtensional origin for the Early Devonian Trans-Suture Suite Geological Magazine, 2008; 145: 235 - 256. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. D. Nance, J. B. Murphy, R. A. Strachan, J. D. Keppie, G. Gutierrez-Alonso, J. Fernandez-Suarez, C. Quesada, U. Linnemann, R. D'lemos, and S. A. Pisarevsky Neoproterozoic-early Palaeozoic tectonostratigraphy and palaeogeography of the peri-Gondwanan terranes: Amazonian v. West African connections Geological Society, London, Special Publications, 2008; 297: 345 - 383. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N.H. WOODCOCK, N.J. SOPER, and R.A. STRACHAN A Rheic cause for the Acadian deformation in Europe Journal of the Geological Society, 2007; 164: 1023 - 1036. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. B. Murphy Geological evolution of middle to late Paleozoic rocks in the Avalon terrane of northern mainland Nova Scotia, Canadian Appalachians: A record of tectonothermal activity along the northern margin of the Rheic Ocean in the Appalachian-Caledonide orogen Geological Society of America Special Papers, 2007; 423: 413 - 435. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. C. Pharaoh, J. A. Winchester, J. Verniers, A. Lassen, and A. Seghedi The Western Accretionary Margin of the East European Craton: an overview Geological Society, London, Memoirs, 2006; 32: 291 - 311. [Abstract] [PDF]
|
|
|
|
 |
|
 J. B. Murphy, J. Fernandez-Suarez, and T. E. Jeffries Lithogeochemical and Sm-Nd and U-Pb isotope data from the Silurian-Lower Devonian Arisaig Group clastic rocks, Avalon terrane, Nova Scotia: A record of terrane accretion in the Appalachian-Caledonide orogen Geological Society of America Bulletin, 2004; 116: 1183 - 1201. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. J. Soper, N. J. SOPER, and N. H. WOODCOCK The lost Lower Old Red Sandstone of England and Wales: a record of post-Iapetan flexure or Early Devonian transtension? Geological Magazine, 2003; 140: 627 - 647. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. F. Dewey, J.F. Dewey, and R.A. Strachan Changing Silurian-Devonian relative plate motion in the Caledonides: sinistral transpression to sinistral transtension Journal of the Geological Society, 2003; 160: 219 - 229. [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, 2002; 201: 47 - 93. [Abstract] [PDF]
|
|
|
|
 |
|
 Late Diagenetic Redistribution of Uranium and Disturbance of the U-Pb Whole Rock Isotope System in a Black Shale Journal of Sedimentary Research, 2000; 70: 1234 - 1245.
|
|
|
|
|
|
J. Dewey and M. Mange Petrography of Ordovician and Silurian sediments in the western Irish Caledonides: tracers of a short-lived Ordovician continent-arc collision orogeny and the evolution of the Laurentian Appalachian-Caledonian margin Geological Society, London, Special Publications, 1999; 164: 55 - 107. [Abstract] [PDF]
|
|
|
|
|
|
H. A. ARMSTRONG, A. W. OWEN, C. T. SCRUTTON, E. N. K. CLARKSON, and C. M. TAYLOR Evolution of the Northern Belt, Southern Uplands: implications for the Southern Uplands controversy Journal of the Geological Society, 1996; 153: 197 - 205. [Abstract] [PDF]
|
|
|
|
|
|
H. A. Armstrong Biotic recovery after mass extinction: the role of climate and ocean-state in the post-glacial (Late Ordovician-Early Silurian) recovery of the conodonts Geological Society, London, Special Publications, 1996; 102: 105 - 117. [Abstract] [PDF]
|
|
|
|
|
|
R. A. BATCHELOR and L. JEPPSSON Late Llandovery bentonites from Gotland, Sweden, as chemostratigraphic markers Journal of the Geological Society, 1994; 151: 741 - 746. [Abstract] [PDF]
|
|
