A. W. A. Rushton, J. K. Ingham, 2000. "Northen England", A revised correlation of Ordovician Rocks in the British Isles, R. A. Fortey, D. A. T. Harpe, J. K. Ingham, A. W Owen, M. A. Parkes, A. W. A. Rushton, N. H. Woodcock
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In northern England Ordovician rocks crop out in the main Lake District inlier and in smaller inliers at Cross Fell, Cautley, Austwick and Teesdale (Fig.1), where they are brought up along the Pennine, Dent and Craven fault systems. The Lake District has a thick lower Ordovician sedimentary succession, the Skiddaw Group, and comparable strata make up much of the Isle of Man. Since the publication of the previous Correlation Chart (Williams et al.1972) fossiliferous Tremadoc rocks have been discovered in the Skiddaw Group (Rushton 1985, 1988).In both the Lake District and Cross Fell the Skiddaw Group successions are followed unconformably by thick arc volcanics, the Eycott and Borrowdale volcanic groups, of possible late Llanvirn to early Caradoc age (Molyneux 1988; Millward & Molyneux 1992).These are overlain, again unconformably, by the Dent Group, neritic marine sediments of mid-Caradoc to Ashgillage. Palaeogeographically, the lower Ordovician rocks of northern England were deposited in a deep shelf or ocean-facing setting, on the SE margin of Iapetus (Bevins et al.1992), and generally they represent a more distal facies than the rocks of the Welsh Basin. The Skiddaw Group is of particular importance as it represents the most complete graptolitic succession in the Arenig, not only in Britain, but anywhere in high palaeogeographical latitudes. It provides a graptolitic zonal standard for the Arenig Series in England and Wales.
Figures & Tables
This Report is revised and expanded from the 1972 publication providing an up-to-the-minute account of the British Ordovician formations and their correlation nationally and internationally. It also includes the most comprehensive treatment of Ireland ever attempted. The reference list of a comprehensive bibliography of papers on the subject published since 1970.
The British sections are the type for the Ordovician System and classical in stratigraphical, tectonic and volcanic studies. The Charts bring together 30 years of research over the period in which plate tectonics has revolutionized our understanding of the Lower Palaeozoic rocks of the British Isles.
This Special Report will be a valuable reference for research and applied geoscientists working with rocks of Ordovician age. It will be of particular interest to those working in, or visiting, the Welsh mountains and the English Lake District.