Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Journal of the Geological Society

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by MORRIS, J. H. Search for Related Content GeoRef GeoRef Citation

The Northern Belt of the Longford-Down Inlier, Ireland and Southern Uplands, Scotland: an Ordovician back-arc basin

Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4, Ireland

The Northern Belt of the Southern Uplands/Longford-Down zone contains two compositionally distinct clastic petrofacies suites each ranging from mid- to late Ordovician age. They extend throughout the length of the belt and are generally separated by a strike fault. The northwestern Metaclast Petrofacies suite is characterized by felsic igneous and metamorphic detritus derived from a continental source to the NW, whereas the southeastern Basic Clast Petrofacies suite contains abundant calc-alkaline detritus derived from an island arc and plutonic/metamorphic root zone complex to the S or SE. A similar source, but located to the north, is indicated for younger clastic sequences of similar composition in the northern part of the Central Belt immediately south of a major sinistral shear zone which defines the boundary between the Northern and Central Belts. It is concluded, in light of other facets of regional geology and possible palaeogeographic configurations, that this pattern reflects a back-arc basin in the Northern Belt, margined by a volcanic arc massif which once occupied the space now represented by the shear zone, and a fore-arc basin to the SE (Central and Southern Belts). The Northern Belt back-arc basin is postulated to have been closed and deformed at the end Ordovician and subsequently overthrust northwestward by the allochthonous, thrust stack imbricated Central and Southern Belts fore-arc sequence at the end Silurian. This, in the Northern Belt, resulted in the development of a major recumbent structure, downward facing on regional (end Silurian) cleavage.

This article has been cited by other articles:

				E. R. Phillips, R. A. Smith, P. Stone, V. Pashley, and M. Horstwood Zircon age constraints on the provenance of Llandovery to Wenlock sandstones from the Midland Valley terrane of the Scottish Caledonides Scottish Journal of Geology, October 1, 2009; 45(2): 131 - 146. [Abstract] [Full Text] [PDF]

				J. W.F. Waldron, J. D. Floyd, A. Simonetti, and L. M. Heaman Ancient Laurentian detrital zircon in the closing Iapetus Ocean, Southern Uplands terrane, Scotland Geology, July 1, 2008; 36(7): 527 - 530. [Abstract] [Full Text] [PDF]

				P. Stone, N. Breward, R. J. Merriman, and R. P. Barnes The interpretation and application of regional geochemistry: lessons from the Paratectonic Caledonides Scottish Journal of Geology, April 1, 2006; 42(1): 65 - 76. [Abstract] [PDF]

				V. R. TROLL, J. P. CHADWICK, R. M. ELLAM, S. McDONNELL, C. H. EMELEUS, and I. G. MEIGHAN Sr and Nd isotope evidence for successive crustal contamination of Slieve Gullion ring-dyke magmas, Co. Armagh, Ireland Geological Magazine, November 1, 2005; 142(6): 659 - 668. [Abstract] [Full Text] [PDF]

				P. Stone, P. Stone, and R.J. Merriman Basin thermal history favours an accretionary origin for the Southern Uplands terrane, Scottish Caledonides Journal of the Geological Society, September 1, 2004; 161(5): 829 - 836. [Abstract] [Full Text] [PDF]

				E.R. Phillips, J.A. Evans, P. Stone, M.S.A. Horstwood, J.D. Floyd, R.A. Smith, M.C. Akhurst, and H.F. Barron Detrital Avalonian zircons in the Laurentian Southern Uplands terrane, Scotland Geology, July 1, 2003; 31(7): 625 - 628. [Abstract] [Full Text] [PDF]

				M. W. Williams, M. Williams, J. Zalasiewicz, A. W. A. Rushton, D. K. Loydell, and R. P. Barnes A new, stratigraphically significant Torquigraptus species (Silurian graptolite) from the Southern Uplands Terrane Scottish Journal of Geology, June 1, 2003; 39(1): 17 - 28. [Abstract] [PDF]

				C. E. Everett, C. E. Everett, D. M. Rye, and R. M. Ellam Source or Sink? An Assessment of the Role of the Old Red Sandstone in the Genesis of the Irish Zn-Pb Deposits Economic Geology, January 1, 2003; 98(1): 31 - 50. [Abstract] [Full Text] [PDF]

				H. A. Armstrong, H. A. Armstrong, J. D. Floyd, L. Tingqing, and H. F. Barron Conodont biostratigraphy of the Crawford Group, Southern Uplands, Scotland Scottish Journal of Geology, December 1, 2002; 38(2): 69 - 82. [Abstract] [PDF]

				H. A. Armstrong, H. A. ARMSTRONG, and A. W. OWEN Terrane evolution of the paratectonic Caledonides of northern Britain Journal of the Geological Society, May 1, 2001; 158(3): 475 - 486. [Abstract] [Full Text] [PDF]

				A. W. OWEN, H. A. ARMSTRONG, and J. D. FLOYD Rare earth element geochemistry of upper Ordovician cherts from the Southern Uplands of Scotland Journal of the Geological Society, February 1, 1999; 156(1): 191 - 204. [Abstract] [PDF]

				C. E. Everett, J. J. Wilkinson, and D. M. Rye Fracture-controlled fluid flow in the Lower Palaeozoic basement rocks of Ireland: implications for the genesis of Irish-type Zn-Pb deposits Geological Society, London, Special Publications, January 1, 1999; 155(1): 247 - 276. [Abstract] [PDF]

				R. P. Barnes and P. Stone Trans-Iapetus contrasts in the geological development of southern Scotland (Laurentia) and the Lakesman Terrane (Avalonia) Geological Society, London, Special Publications, January 1, 1999; 160(1): 307 - 323. [Abstract] [PDF]

				Y. OGAWA Tectonostratigraphy of the Glen App area, Southern Uplands, Scotland: anatomy of an Ordovician accretionary complex Journal of the Geological Society, August 1, 1998; 155(4): 651 - 662. [Abstract] [PDF]

				A. R. HUTCHISON and G. J. H. OLIVER Garnet provenance studies, juxtaposition of Laurentian marginal terranes and timing of the Grampian Orogeny in Scotland Journal of the Geological Society, June 1, 1998; 155(3): 541 - 550. [Abstract] [PDF]

				C. R. Van Staal, J. F. Dewey, C. M. Niocaill, and W. S. McKerrow The Cambrian-Silurian tectonic evolution of the northern Appalachians and British Caledonides: history of a complex, west and southwest Pacific-type segment of Iapetus Geological Society, London, Special Publications, January 1, 1998; 143(1): 197 - 242. [Abstract] [PDF]

				D. M. WILLIAMS, J. HARKIN, and A. H. N. RICE Umbers, ocean crust and the Irish Caledonides: terrane transpression and the morphology of the Laurentian margin Journal of the Geological Society, October 1, 1997; 154(5): 829 - 838. [Abstract] [PDF]

				C. BROWN and J.P. WHELAN Terrane boundaries in Ireland inferred from the Irish Magnetotelluric Profile and other geophysical data Journal of the Geological Society, June 1, 1995; 152(3): 523 - 534. [Abstract] [PDF]

				Discussion on the structure of the western part of the Southern Uplands of Scotland Journal of the Geological Society, August 1, 1994; 151(4): 732 - 734. [Abstract] [PDF]

				D.T. NEEDHAM The structure of the western part of the Southern Uplands of Scotland Journal of the Geological Society, April 1, 1993; 150(2): 341 - 354. [Abstract] [PDF]

				A. W. Owen and E. N. K. Clarkson Trilobites from Kilbucho and Wallace's Cast and the location of the Northern Belt of the Southern Uplands during the late Ordovician Scottish Journal of Geology, May 1, 1992; 28(1): 3 - 17. [Abstract] [PDF]

				A. P. M. VAUGHAN and J. D. JOHNSTON Structural constraints on closure geometry across the Iapetus suture in eastern Ireland Journal of the Geological Society, February 1, 1992; 149(1): 65 - 74. [Abstract] [PDF]

				R. E. Bevins, B. J. Bluck, P. J. Brenchley, R. A. Fortey, C. P. Hughes, J. K. Ingham, and A. W. A. Rushton Ordovician Geological Society, London, Memoirs, January 1, 1992; 13(1): 19 - 36. [Abstract] [PDF]

				A. W. A. Rushton and P. Stone Terrigenous input to the Moffat Shale sequence, Southern Uplands Scottish Journal of Geology, December 1, 1991; 27(2): 167 - 169. [Abstract] [PDF]

				W. D. HUFF, T. B. ANDERSON, C. C. RUNDLE, and G. S. ODIN Chemostratigraphy, K-Ar ages and illitization of Silurian K-bentonites from the Central Belt of the Southern Uplands-Down-Longford terrane, British Isles Journal of the Geological Society, October 1, 1991; 148(5): 861 - 868. [Abstract] [PDF]

				S. P. TODD, F. C. MURPHY, and P. S. KENNAN On the trace of the Iapetus suture in Ireland and Britain Journal of the Geological Society, October 1, 1991; 148(5): 869 - 880. [Abstract] [PDF]

				D. M. WILLIAMS and D. A. T. HARPER End-Silurian modifications of Ordovician terranes in western Ireland Journal of the Geological Society, February 1, 1991; 148(1): 165 - 171. [Abstract] [PDF]

				J. A. Evans, P. Stone, and J. D. Floyd Isotopic characteristics of Ordovician greywacke provenance in the Southern Uplands of Scotland Geological Society, London, Special Publications, January 1, 1991; 57(1): 161 - 172. [Abstract] [PDF]

				Discussion on detrital mineral ages from the Southern Uplands using 40Ar-39Ar laser probe Journal of the Geological Society, October 1, 1990; 147(5): 882 - 884. [Abstract] [PDF]

				P. R. DIXON, A. P. LeHURAY, and D. M. RYE Basement geology and tectonic evolution of Ireland as deduced from Pb isotopes Journal of the Geological Society, February 1, 1990; 147(1): 121 - 132. [Abstract] [PDF]

				A. H. G. MITCHELL Short Paper: Arc reversal in the Scottish Southern Uplands? Journal of the Geological Society, October 1, 1989; 146(5): 736 - 737. [Abstract] [PDF]

				M. T. STYLES, P. STONE, and J. D. FLOYD Short Paper: Arc detritus in the Southern Uplands: mineralogical characterization of a 'missing' terrane Journal of the Geological Society, June 1, 1989; 146(3): 397 - 400. [Abstract] [PDF]

				S. KELLEY and B. J. BLUCK Short Paper: Detrital mineral ages from the Southern Uplands using 40Ar-39Ar laser probe Journal of the Geological Society, June 1, 1989; 146(3): 401 - 403. [Abstract] [PDF]

				D. M. Williams, H. A. Armstrong, and D. A. T. Harper The age of the South Connemara Group, Ireland, and its relationship to the Southern Uplands Zone of Scotland and Ireland Scottish Journal of Geology, March 1, 1988; 24(3): 279 - 287. [Abstract] [PDF]

				J. K. LEGGETT The Southern Uplands as an accretionary prism: the importance of analogues in reconstructing palaeogeography Journal of the Geological Society, October 1, 1987; 144(5): 737 - 751. [Abstract] [PDF]

				D. H. W. HUTTON and F. C. MURPHY The Silurian of the Southern Uplands and Ireland as a successor basin to the end-Ordovician closure of Iapetus Journal of the Geological Society, October 1, 1987; 144(5): 765 - 772. [Abstract] [PDF]

				G. KELLING, P. DAVIES, and J. HOLROYD Style, scale and significance of sand bodies in the Northern and Central Belts, southwest Southern Uplands Journal of the Geological Society, October 1, 1987; 144(5): 787 - 805. [Abstract] [PDF]