Style, scale and significance of sand bodies in the Northern and Central Belts, southwest Southern Uplands
- 1 September 1987
- journal article
- Published by Geological Society of London in Journal of the Geological Society
- Vol. 144 (5) , 787-805
- https://doi.org/10.1144/gsjgs.144.5.0787
Abstract
Sedimentological and biostratigraphical data from the Rhinns of Galloway and adjacent areas in SW Scotland confirm that deep-water depositional systems consistently operated along, and were sourced from, the northwestern margin of an asymmetrical basin during the late Ordovician and early Silurian, while pelagic facies accumulated simultaneously to the SE, providing a scenario analogous to many modern trench systems. Most of the observed sedimentological anomalies, with regard to this general model, can be explained within the context of the varied styles of trench-filling depositional systems, briefly reviewed here, and the major stratigraphic and sedimentologic features can be best explained in terms of a geotectonically evolving fore-arc region. Two main phases of development are recognized: (a) Llandeilo-late Ashgill: during this time interval the fore-arc trench region was tectonically juxtaposed against an active continental margin arc. Small- to medium-scale, SE-prograding sand-rich fans were formed within a relatively narrow trench, leading to axial diversion of the fans, initially to NE but later mainly to SW. Simultaneously a coarse volcanilithic sediment apron, flanking the arc, migrated gradually northeastwards, probably in response to relative fault displacement of the arc and trench; (b) Llandovery: during this time interval the fore-arc trench region was dominated by a variety of mainly fan-type depositional systems which were exclusively sourced (at least until the uppermost Llandovery) from the northwestern margin. The juxtaposition of coeval depositional systems differing significantly in sedimentological style and composition strongly suggests that the Llandovery sedimentation in this region occurred in several structurally separated sub-basins within the main trench system.This publication has 20 references indexed in Scilit:
- Along-strike variation in the stratigraphical and structural profile of the Southern Uplands Central Belt in Galloway and DownJournal of the Geological Society, 1987
- Stratigraphy in an accretionary prism: the Ordovician rocks in North Down, IrelandEarth and Environmental Science Transactions of the Royal Society of Edinburgh, 1983
- The Cambro‐Ordovician Cap Enragé Formation, Queébec, Canada: conglomeratic deposits of a braided submarine channel with terracesSedimentology, 1982
- Stratigraphy of a flysch succession: the Ordovician of W Nithsdale, SW ScotlandEarth and Environmental Science Transactions of the Royal Society of Edinburgh, 1982
- Sedimentology, volcanism, structure and metamorphism of the northern margin of a Lower Palaeozoic accretionary complex; Bail Hill-Abington area of the Southern Uplands of ScotlandGeological Society, London, Special Publications, 1982
- Evolution of the Taupo-Hikurangi subduction systemTectonophysics, 1981
- Salt Tectonics and Basement Fractures: Key Controls of Recent Sediment Distribution on the Balearic Rise, Western MediterraneanPublished by Smithsonian Institution ,1979
- The Turbidite Concept in BritainPublished by Elsevier ,1964
- VI.—The Petrology and Sedimentation of Upper Ordovician Rocks in the Rhinns of Galloway, South-west ScotlandTransactions of the Royal Society of Edinburgh, 1962
- THE STRATIGRAPHY AND STRUCTURE OF THE ORDOVICIAN ROCKS OF THE RHINNS OF GALLOWAYQuarterly Journal of the Geological Society, 1961