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Figure
1.1
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Palaeogeography (palaeocoastline) of (a) the Early Triassic (InduanOlenekian) world c. 250 Ma, showing Pangaea, which had been assembled from Laurasia and Gondwanaland, and (b) the Late Triassic (Rhaetian) world c. 200 Ma. At the end of the Triassic Period Pangaea began to rift apart. The maps show the main areas of land and mountains, with ‘modern’ coastlines superimposed for reference (after Smith et al., 1994).
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Figure
1.2
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The fates of many animal groups in the sea were determined dramatically by the end-Permian mass extinction event, some suffering major restrictions in diversity, others being entirely wiped out. (Based on the work of J.J. Sepkoski, Jr.) The width of the bands is proportional to the number of contemporary families present.
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Figure
1.3
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Permian stratigraphy, showing the international scale (Jin Yugan et al., 1997), and main equivalent divisions from successions in Germany and central Europe, Russia, and North America. The Illawarra magnetic reversal event (IR) is documented in the top Wordian Stage, and high in the Rotliegendes, so the ‘Zechstein’ lithostratigraphical unit falls in the Capitanian Stage or higher. (Based on Jin Yugan et al., 1997 and Wardlaw, 2000.)
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Figure
1.4
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The Triassic stratigraphy of the English Midlands and the southern North Sea, showing modern terminology (Warrington et al., 1980) and classic terminology (Hull, 1869) of the major divisions.
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Figure
1.5
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The principal PermoTriassic sedimentary basins and syndepositional normal faults in England. Intensity of stippling indicates sediment thicknesses. Abbreviations: CB, Cheshire Basin; CF, Clopton Fault system; DB, Dorset Basin; EMF, East Malvern Fault; IF, Inkberrow Fault; KB, Knowle Basin; LBB, Lyme Bay Basin; NB, Needwood Basin; PeB, Pewsey Basin; SB, Stafford Basin; SoB, Solway Basin; WaB, Wardour Basin; WB, Worcester Basin; WRRF, Wem-Red Rock Fault system.
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Figure
1.6
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Structural cross-sections through the Worcester Basin (a), and Cheshire Basin (b). Vertical exaggeration is × 2.5. (After Chadwick and Evans, 1995.)
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Figure
1.7
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The PermoTriassic basins in the Southern Uplands of Scotland and the LongfordDown region of Ireland. The Permian outcrop north-west of the Southern Uplands Fault and south-east of the Iapetus Suture are not shown see Figure 2.1. (After Anderson et al., 1995.)
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Figure
1.8
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The major tectonic elements of the Inner Moray Firth Basin. (After Andrews et al., 1990.)
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Figure
1.9
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Palaeogeography of Britain and the North Sea in the Permian Period. (a) Palaeogeography of Britain and adjacent areas during the Early and Mid Permian epochs. (b, c) Lithofacies and environments in the Southern North Sea Basin, during the Mid Permian epoch (Upper Rotliegendes), map (b) and northsouth cross-section (c). The Southern North Sea Basin and North German basin together make up the ‘Rotliegendes Basin’. Based on Glennie (1972), Marie (1975), and Anderton et al. (1979).
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Figure
1.10
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Palaeogeography of Britain in (a) the Anisian Age (Mid Triassic; c. 245 Ma). (After Warrington and Ivimey-Cook, 1992) Figure 1.10contd. Palaeogeography of Britain in (b) NorianRhaetian times (Late Triassic; c. 205 Ma).
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Figure
1.11
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Deserts today provide excellent analogues for understanding the ancient desert sedimentary systems of the British PermoTriassic red beds. (a) Deserts derive sediment from mountain chains, first as coarse-grained alluvial fans (intermittent, braided streams build up ‘cones’ of material (breccias and conglomerates) at the point where they discharge onto a plain). Farther from source, the sediment is broken down into finer-grained sands and muds mainly through aeolian processes (abrasion through wind transport, weathering etc.). Perennial lakes develop during the wet season, and may produce evaporites as they dry out. (b) Dune fields develop by the accumulation of sand carried by prevailing wind and small ephemeral streams; the material tends to accumulate as sand dunes. (c) The principal forms of dune.
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Figure
2.1
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Map showing the outcrop of Permian rocks in Great Britain. Some major basinal areas are indicated. GCR Permian red-bed sites are numbered as follows: (1) ClashachCovesea; (2) Masonshaugh Quarries; (3) Corrie Shore; (4) Hapland Burn; (5) Locharbriggs North Quarry; (6) Crime Rigg Quarry; (7) Saltom Bay; (8) Burrells Quarry; (9) Cowraik Quarry; (10) George Gill; (11) Hilton Beck; (12) Stenkrith Beck; (13) River Belah; (14) Sling Common; (15) Osebury Rock; (16) Kinver Edge; (17) Shoalstone; (18) Saltern Cove; (19) Roundham Head; (20) Oddicombe Beach; (21) Coryton’s Cove; (22) Dawlish; (23) Orcombe Rocks.
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Figure
2.2
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The distribution of PermoTriassic sediments around Elgin, Morayshire. GCR sites are: (1) ClashachCovesea (Permian); (2) Masonshaugh Quarries (Permian); (3) Burghead (Triassic); (4) Lossiemouth (Triassic). Based on Peacock et al. (1968) and Benton and Walker (1985).
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Figure
2.3
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The Permian Hopeman Sandstone Formation in the cliffs between Clashach and Covesea. (a) Cliff section (looking east) showing cross-bed dune sets representing a complex star dune. (b) Sand dune deposits north of Covesea Quarry, showing localized synsedimentary deformation; part of dune No. 5 on Figure 2.4 (Photos: (a) C. J. MacFadyen, (b) P. Turner.)
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Figure
2.4
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Reconstruction of the large-scale star dunes shown by outcrops in the ClashachCovesea section. Numbers (1) to (9) are the individual dunes, as referred to in the text. (After Clemmensen, 1987.)
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Figure
2.5
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The Hopeman Sandstone Formation at Masonshaugh. (a) Detail of the faulted contact between the Burghead Sandstone Formation (Triassic in age) and the Hopeman Sandstone Formation (Permian), showing the major fault zone, western termination of the Lossiemouth Fault. (b) The regional zonation of barite, fluorspar, and silica cements in the Hopeman Sandstone Formation along the north coast of Morayshire. (c) Details of the cement zone around the Lossiemouth Fault as it cuts across the beach at Masonshaugh at NJ 131 693, showing zones of fluorite and silicified cements in the sandstone. (After Edwards et al.,1993.)
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Figure
2.6
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The Lossiemouth Fault cutting across the foreshore at Masonshaugh Quarry, bringing the Hopeman Sandstone Formation (HSF) into contact with the Burghead Sandstone Formation (BSF). The sandstone is heavily mineralized around the fault zone, and it weathers slowly. (Photo: M. J. Benton.)
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Figure
2.7
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Aeolian deposits at Corrie Shore, Arran. (a) Coastal exposure showing cross-bedding indicative of aeolian dunes. (Photo: C. MacFadyen.) Figure 2.7contd. Aeolian deposits at Corrie Shore, Arran. (b) A fulgurite, top view of the site of a lightning strike. (c) Dune cross-bedded Corrie Sandstone overlain unconformably by the Brodick Breccia. The compass is 100 mm long. (Photos b,c: D.E.G. Briggs.)
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Figure
2.8
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The aeolian and fluvial successions at Corrie Shore, Arran. (a) Generalized succession through the aeolian Corrie Sandstone, showing proposed division into seven erg megacycles (IVII), and 34 superimposed units. (b) Detail of part of a dune sequence from low in the succession, showing dune foresets and interdune strata. (c) Succession of breccia units in the Brodick Beds at Corrie Shore; m, mudcracks. Based on Astin and MacDonald (1983), Clemmensen and Abrahamsen (1983), and Clemmensen and Hegner (1991).
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Figure
2.9
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Palaeoenvironmental reconstruction for the Corrie Sandstone erg. Mainly slipfaceless draas with superimposed crescentic dunes alternated with interdune flats, the latter associated with small barchans. (From Clemmensen and Abrahamsen, 1983.)
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Figure
2.10
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Sedimentology of the Hapland Burn locality. (a) Generalized sedimentary log, with palaeoenvironmental interpretations. Either Ordovician or Carboniferous rocks are present beneath the unconformity at different parts of the site. (b) Reconstructed cross-section of the main units through the east side of the Thornhill Basin. In (b), main palaeoenvironments are numbered: 1, braided stream, sandy breccia, and trough cross-beds; 2, sheet flood; 3, ephemeral stream; 4, temporary lake/siltstone; 5, aeolian sand. (After Brookfield 1980, 1984.)
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Figure
2.11
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Sedimentology of the Locharbriggs Sandstone Formation in the Locharbriggs Quarries. (a) The Dumfries Basin, showing location of the Locharbriggs Quarries (arrow). (b) Plan view of the three quarries, the middle one of which is the GCR site. (c) Sketches of the exposures of the cross-bed sets and bounding surfaces in the three quarries; (A) to (F) correspond to the faces marked on the plan views in (b). (All from Brookfield, 1977.)
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Figure
2.12
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The working area of Locharbriggs North Quarry (see also Figure 2.11b). (Photo: C. MacFadyen.)
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Figure
2.13
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The sequence of the Yellow Sands and overlying Zechstein deposits in the western part of Sherburn Hill Sand Pit, Crime Rigg. (a) General overview and (b) close up. The face in (b) shows a transverse section through a linear mound or draa. Foresets dip to the left and right, and there are numerous third-order bounding surfaces. Exposed thickness of the Yellow Sands here is about 25 m. (Photo: L. B. Clemmensen.)
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Figure
2.14
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Sedimentology of the Yellow Sands at Crime Rigg. (a) Summary log through the sequence; (b) drawing of the west face at Sherburn Hill Sand Pit (NZ 344 417), showing a trough-cross-bedded dune set, with part of the face (from 0 to 50 m) transverse to the palaeocurrent, and the other part (from 60 to 140 m) sub-parallel to the palaeocurrent. (From Clemmensen, 1989).
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Figure
2.15
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Palaeogeographical map of north-east England during the time of deposition of the Yellow Sands, showing the position of the nine major SWNE-trending draa ridges. These ridges are wider and more closely spaced than in modern examples of parallel draa ridges, possibly because of the coarse-grain size of the Yellow Sands. (Based on Steele, 1983; and Clemmensen, 1989.)
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Figure
2.16
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Proposed structure of the Yellow Sands draas and dunes, showing two stages in their evolution, (a) initial lateral migration, followed by (b) vertical accretion. The vertical scale is exaggerated for illustrative purposes. (After Clemmensen, 1989).
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Figure
2.17
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Simplified sedimentary log of the succession at Saltom Bay, with the Permian Brockram resting unconformably on the Carboniferous Whitehaven Sandstone Formation and succeeded by the St Bees Evaporite and St Bees Shale formations. A graphical facies log of the Basal Breccia is shown. Note the deep, weathered fissure in the top of the sandstone filled with brockram. (After Macchi and Meadows, 1987.)
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Figure
2.18
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The Saltom Dolomite of the St Bees Evaporite Formation resting on the uneven top surface of the Brockram, at the south-west end of Barrowmouth Beach, Saltom Bay. The hammer is 0.33 m long. (Photo: D. B. Smith.)
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Figure
2.19
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Diagram of stratigraphical relationships of the sub-Permian strata, and the Permian Brockram and higher breccia facies and basinal marine deposits in the Appleby and Cumbrian Coast groups, west Cumbria. (After Akhurst et al., 1997.)
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Figure
2.20
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Block reconstructions of major sedimentary environments represented by (a) the Brockram, and (b) the St Bees Shale Formation. (From Akhurst et al., 1997.)
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Figure
2.21
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Simplified geological map of the Vale of Eden and the surrounding area, including palaeowind directions for the Penrith Sandstone. GCR localities are: (1) Burrells Quarry; (2) Cowraik Quarry; (3) George Gill; (4) Hilton Beck; (5) Stenkrith Beck; (6) River Belah. Based on Waugh (1970b), Burgess and Holliday (1974), and Younger and Milne (1997).
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Figure
2.22
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Diagrammatic NWSE section through the Vale of Eden basin, showing the Permian succession. The section is about 55 km long. (After Arthurton et al., 1978.)
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Figure
2.23
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Penrith Brockram at Burrells Quarry; a poorly sorted, clast-supported breccio-conglomerate. (Photo: P. Turner.)
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Figure
2.24
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The Penrith Sandstone at George Gill, showing aeolian dune cross-bedding (lighter line) and bounding surfaces (heavier line), as exposed in crags on the southern side of the valley. Dune foreset orientations are indicated (dip in degrees/dip direction, degrees from north). (After Macchi and Meadows, 1987.)
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Figure
2.25
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The geology of the Eden Shales. (a) Sedimentary log taken in Hilton Beck. (b) Palaeogeography of the southern end of the Vale of Eden during deposition of the Hilton Plant Beds. (After Clarke, 1965b, and Burgess and Holliday, 1979.)
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Figure
2.26
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The Stenkrith Brockram, recorded in a series of logs from High Stenkrith to Stenkrith Park, along Stenkrith Beck. (After Macchi and Meadows, 1987.)
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Figure
2.27
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Sections through the Penrith Sandstone exposed between Belah Bridge (1) and Belah Scar (4). (After Macchi and Meadows, 1987.)
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Figure
2.28
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Permian sediments on Belah Scar: Penrith Sandstone with brockram lenses cut by an extensional fault downthrowing to the west. The cliff is about 6 m high. (Photo: P. Turner.)
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Figure
2.29
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The Bridgnorth Sandstone at Kinver Edge, showing (a) large-scale barchanoid aeolian dune bedding, and (b) a close up of the aeolian bounding surfaces. The hammer is about 300 mm long. (Photos: P. Turner.)
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Figure
2.30
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Stratigraphy of the Permian successions of the East and South Devon basins. Formal divisions for the Crediton Trough and Exeter area are from Edwards et al. (1997), and the successions around Torquay and Teignmouth are updated tentatively from Smith et al. (1974), Selwood et al. (1984), and Warrington and Scrivener (1990).
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Figure
2.31
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Depositional basins and sediment transport trends in the Permian of Devon. GCR sites are: (1) Shoalstone; (2) Saltern Cove; (3) Roundham Head; (4) Oddicombe Beach; (5) Coryton’s Cove; (6) Dawlish; (7) Orcombe Rocks. (After Laming, 1982.)
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Figure
2.32
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Large-scale map of the sets of PermoTriassic sandstone fissure fills (Neptunian dykes) on Shoalstone Beach, showing older and younger generations of dykes. (After Richter, 1966.)
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Figure
2.33
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The Tor Bay Breccia in Saltern Cove. (Photo: D. Evans.)
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Figure
2.34
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Burrows from the Tor Bay Breccia of Waterside Cove, shown as a reconstruction (a), in vertical section, with meniscate packing structures (b), and in horizontal section, with oriented clasts (c). (After Ridgeway, 1974.)
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Figure
2.35
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The Tor Bay Breccia at Roundham Head. (a) Contact between sandstone and breccia. (Photo: P. Turner.) Figure 2.35contd. The Tor Bay Breccia at Roundham Head. (b) Coarse, imbricated, red, sandy fan breccia composed of locally derived angular clasts of Devonian rocks, mainly limestone. (c) Crudely stratified gravels interbedded with finer-grained cross-stratified gravel. In both (b) and (c) the palaeoflow direction is to the right (west). (Photos: P. Turner.)
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Figure
2.36
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Rose diagrams of palaeowind directions from aeolian foreset orientations for the Tor Bay Breccia and the Dawlish Sandstone Formation. (From Laming, 1982.)
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Figure
2.37
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The cliff section at Petitor and Oddicombe, showing the three faults that bring the Devonian and the Permian sediments into direct contact. (From Laming, 1982.)
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Figure
2.38
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The Oddicombe Breccia at Oddicombe Beach, showing intercalated coarse sands and breccias, with imbrication of the pebbles. (Photo: P. Turner.)
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Figure
2.39
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Palaeogeography of South Devon during the EarlyMid Permian epochs, showing the mountainous hinterland of uplifted Devonian and Carboniferous sediments, the main depositional basins, and the present-day coastline. (After Laming, 1982.)
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Figure
2.40
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Debris flow in the Teignmouth Breccia at Coryton’s Cove. Near the top of the photograph is a sharp transition to an overlying sheetflood deposit. (Photo: P. Turner.)
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Figure
2.41
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Aeolian dune sands in the Dawlish Sandstone Formation. The large-scale cross-bedded unit in the middle of the section represents an eastwardly migrating barchanoid draa. It is interbedded with fluvial sheetflood sands and gravels (Photo: P. Turner.)
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Figure
2.42
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Summary log through the Exmouth Mudstone and Sandstone Formation in the coast section between Orcombe Point and Straight Point, east of Exmouth. (From Selwood et al., 1984.)
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Figure
2.43
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Sandstones of the Exmouth Mudstone and Sandstone Formation at Orcombe Point, showing a transition from planar to tabular cross beds. Prominent laminae are cemented with calcite. Note the deformed foresets, upper left (arrowed). The hammer is 0.3 m long. (Photo: P. Turner.)
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Figure
3.1
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Map showing the distribution of Triassic rocks in Great Britain. GCR Triassic red-bed sites are indicated: (1) Burghead; (2) Lossiemouth; (3) Gruinard Bay; (4) Eyre Burn; (5) Gribun; (6) King’s Cave to Drumadoon; (7) Fleswick to St Bees; (8) Burton Point; (9) Hilbre Island; (10) Thurstaston; (11) The Dungeon; (12) Dee Cliffs; (13) Bickerton Hill; (14) Frodsham; (15) Red Brow; (16) Grinshill; (17) Nottingham Castle; (18) Styrrup Quarry; (19) Scrooby Top Quarry; (20) Colwick; (21) Hulme Quarry; (22) Brocton; (23) Wollaston Ridge; (24) Claverley Road Cutting; (25) Burcot; (26) Shrewley; (27) Sutton Flats; (28) Barry Island; (29) Hayes Point to Bendrick Rock; (30) Sully Island; (31) Aust Cliff (see Chapter 4); (32) Budleigh Salterton; (33) Ladram Bay to Sidmouth. TheTriassic red-bed/Penarth Group sites described in Chapter 4 are shown on Figure 4.5.
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Figure
3.2
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Measured sections at four sites in the Burghead GCR site, showing characteristic sequences and lateral relationships. (After Frostick et al., 1988.)
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Figure
3.3
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The Burghead Sandstone Formation in Burghead Cliffs, Masonshaugh site. The cross-bedding in the sand dune deposits of the Hopeman Sandstone Formation is of a much larger scale than the cross-bedding in these water-lain deposits. (Photo: C. MacFadyen.)
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Figure
3.4
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Occurrence of the Lossiemouth Sandstone Formation in its type location, in Lossiemouth, and on the foreshore north of the town.
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Figure
3.5
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Lossiemouth East Quarry, showing water-laid Burghead Sandstone Formation at the base, and large aeolian cross-bedded sandstone sets in the Lossiemouth Sandstone Formation above. The face is about 9 m high.(Photo: C. MacFadyen.)
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Figure
3.6
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Lossiemouth East Quarry: view of heavily jointed, dune cross-bedded sandstones at the eastern end of the site. (Photo: M. J. Benton.)
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Figure
3.7
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The Cherty Rock on the foreshore north of Lossiemouth, a close-up showing its fractured nature. (Photo: C. MacFadyen.)
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Figure
3.8
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‘New Red Sandstone’ (including Triassic) outcrops on the west coast of Scotland, the Hebridean islands and Arran. GCR sites are numbered: (1) Gruinard Bay; (2) Eyre Burn; (3) Gribun.; (4) Kings Cave to Drumadoon. There are possible occurrences on Islay and the Kintyre Peninsula. (After Warrington et al., 1980.)
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Figure
3.9
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Stratigraphical columns for the ‘New Red Sandstone’ (including Triassic) of the western Highlands, the Hebrides, and Arran. (*The Penarth Group is known only on Mull and Morvern). M, macrofossils; m, microfossils. (After Warrington et al., 1980.)
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Figure
3.10
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Stornoway Formation sediments at Gruinard Bay, with geological hammer for scale (arrowed). (Photo: C. MacFadyen.)
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Figure
3.11
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The calcrete (‘cornstone’) facies at Gruinard Bay. Stages 1 to 4 represent informal measures of palaeosol maturity based on depth of palaeosol and intensity of palaeosol formation. (After Steel, 1974b.)
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Figure
3.12
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Close-up of a vertical nodular structure interpreted as a large rhizocretion, within a palaeosol at Gruinard Bay. (Photo: P. Turner.)
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Figure
3.13
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Triassic sediments at the Eyre Burn GCR site; (a) a conglomerate deposited as a sheet flood on an alluvial fan; and (b) a palaeosol, comprising a siltstone with calcretes. (Photos: C. MacFadyen.)
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Figure
3.14
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The Triassic section in the GCR site at Eyre Burn (left), and through the neighbouring site at Rudha na’ Leac (right), showing the transition upwards from conglomerates deposited by braided rivers in alluvial fans at the base, through fine sandstones and palaeosols. (After Bruck et al., 1967.)
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Figure
3.15
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The Stornoway Formation at Gribun: (a) the unconformable junction between the banded and tilted Moine basement and the Stornoway Formation, marked by a hammer; and (b) a palaeosol horizon within beds of coarse sandstone. (Photos: C. MacFadyen.)
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Figure
3.16
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Outcrop of red sandstones of the Lamlash Sandstone Formation on the wave-cut platform on the foreshore at Drumadoon, looking south. (Photo: C. MacFadyen.)
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Figure
3.17
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The Triassic sediments between King’s Cave and Drumadoon: (a) succession of siltstones and mudstones of the Auchenhew Mudstone Formation; and (b) burrows, cf. Cylindricum, on the surface of a ripple-marked, fine-grained sandstone. (Photos: C. MacFadyen.)
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Figure
3.18
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(a) Map of the west coast of Arran; (b) sedimentary logs through the King’s Cave to Drumadoon Triassic succession, and (c) diagrammatic NWSE cross-section of the foreshore and cliffs (see map (a) for location). The logs are composed from measurements made in seven locations shown on the map. (After Pollard and Steel, 1978.)
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Figure
3.19
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Stratigraphical columns for the Triassic successions of southern Scotland and Cumbria, and the East Irish Sea and Cheshire Basin areas. M, macrofossils; m, microfossils. Based on Warrington et al. (1980), Jackson et al. (1987), Wilson (1993) and Ivimey-Cook et al. (1995), Jackson and Johnson (1996), Akhurst et al. (1997) and Warrington (1997b).
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Figure
3.20
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The Lower Triassic St Bees Sandstone Formation at St Bees Head on the Cumbrian coast showing vertical profiles through transverse bars. (a) Plane-bedded sandstones (pbs) overlain by planar/tabular cross-bedded sandstones (p/t, cbs), and then more plane-bedded and cross-bedded sandstones (pbs, cbs) with multiple erosion surfaces; rucksack for scale. (b) Multiple cross-bedded units and a large sinusoidal bedform with re-activation surfaces. (Photos: P. Turner.)
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Figure
3.21
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The Lower Triassic St Bees Sandstone Formation at St Bees Head on the Cumbrian coast. (a) Cross-bedded sandstones that have been distorted shortly after deposition. (b) A scour-and-fill structure, in which cross-bedded sandstones occupy a hollow eroded into the underlying sandstones. (Photos: P. Turner.)
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Figure
3.22
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Depositional models for the St Bees Shale and the St Bees Sandstone formations, showing major sediment types, and proposed sedimentary environments. (After Akhurst et al., 1997.)
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Figure
3.23
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Two sedimentary logs through the Kinnerton Sandstone Formation, recorded at two localities at Burton Point, showing a mix of fluvial styles. (After Macchi and Meadows, 1987.)
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Figure
3.24
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(a) Cross-bedded units in the Kinnerton Sandstone Formation at Burton Point, with major synsedimentary slumping. (b) Pebbly sandstones with large-scale planar-tabular cross-bedding in the lower part of the Chester Pebble Beds Formation. (Photos: P. Turner.)
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Figure
3.25
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The Ormskirk Sandstone Formation on the southern point of Hilbre Island, showing planar-bedded and cross-bedded sandstone units. (Photo: M. J. King.)
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Figure
3.26
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The Ormskirk Sandstone Formation on the southern point of Hilbre Island, close to the site that yielded trace fossils, including vertebrate footprints. (Photo: M. J. King.)
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Figure
3.27
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Simplified graphic sedimentary log through the Ormskirk Sandstone Formation at the southern tip of Hilbre Island. (After King and Thompson, 2000a.)
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Figure
3.28
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Contorted bedding in the Thurstaston Soft Sandstone Member. The area of Figure 3.29a is at the far north-western end of the section shown here. (After Rice, 1939b.)
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Figure
3.29
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Thurstaston Common road cut. (a) The lower bounding erosion surface of the Thurstaston Hard Sandstone Member, overlying the Wilmslow Sandstone Formation. (b) Deformed cross-bedding in contortion unit 1 in the Thurstaston Soft Sandstone Member. Field of view of (b) is about 5 m. (Photos: (a) M. J. Benton, (b) P. Turner.)
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Figure
3.30
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Sedimentary log of the Wilmslow Sandstone and Tarporley Siltstone formations in the stream section at The Dungeon. (P. Turner, unpublished information.)
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Figure
3.31
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a The geology of the Cheshire Basin, shown as a simplified geological map. See also Figure 3.31b. The key feature is the Wem-Red Rock fault system to the east, and major subsidence against that system during deposition of the Triassic successions. This explains why the sequences are thicker in the east and south-east than in the hinge zone to the north-west. Based on Wilson (1993), Evans et al. (1993), and Plant et al. (1999).
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Figure
3.31
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b The geology of the Cheshire Basin, shown as a schematic cross-section. Based on Wilson (1993), Evans et al. (1993), and Plant et al. (1999).
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Figure
3.32
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Diagrammatic section at the Dee Cliffs GCR site, showing the range of fluvial styles in the Chester Pebble Beds Formation. Logged by P. Turner. Figure 3.33 The Chester Pebble Beds Formation at Dee Cliff, (a) the lower planar-tabular cross-bedded sets at the picnic site; (b) stratigraphically higher plane-bedded sandstones with thin (upper left) scour fills. The height of the section in (b) is about 10 m. (Photos: P. Turner.)
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Figure
3.34
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West side of the Peckforton Hills, looking north, as shown in a classic view by Hull (1869).
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Figure
3.35
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The geology of Bickerton Hill; (a) a map of the outcrop of the main divisions of the Triassic System; (b) cross-section (XY), showing the faulted contact of the Wilmslow Sandstone Formation and the Tarporley Siltstone Formation, with associated mineralization. (From Naylor et al., 1989b.)
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Figure
3.36
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The Frodsham site displays (a) aeolian dune cross-bedding in the railway cutting and (b) a spectacular dome-shaped structure in an adjacent quarry. (Photos: D.B. Thompson.)
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Figure
3.37
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Sections through the aeolian Frodsham Soft Sandstone Member on the north side of the railway cutting at Frodsham. Sections (a) to (d) fit together as a continuous strip running from WSW (a) to ENE (d). These diagrams show the main dune (No. 3) throughout, while dunes No. 4 and No. 5 appear at the right-hand end of strip (d). Joints are omitted. (After Thompson, 1969.)
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Figure
3.38
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Aeolian dune cross-bedding in a section of the Frodsham Soft Sandstone Member on the High Street of Frodsham village. (Photo: D. B. Thompson.)
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Figure
3.39
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The section at Red Brow, showing the succession of red sandstones and mudstones. (Photo: M. J. Benton.)
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Figure
3.40
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Sedimentary logs measured through the Red Brow section, showing the interplay of facies AE. (From Ireland et al., 1978.)
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Figure
3.41
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Sedimentary structures and trace fossils from the Red Brow section, indicative of an intertidal depositional regime. (a) Mud cracks viewed from above, with the cracks filled with overlying sandstone. (Photo: M. J. Benton.) Figure 3.41 contd. Sedimentary structures and trace fossils from the Red Brow section, indicative of an intertidal depositional regime. (b) Symmetrical ripple marks. (c) Numerous scattered burrows (Planolites), on the lower surface of a mudstone bed. (Photos: M. J. Benton.)
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Figure
3.42
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The Grinshill localities. The map is based on published maps of the British Geological Survey (BGS 1:63 3000 scale Geological Sheet 138, Wem), and on field observations by M.J.B.
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Figure
3.43
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The operational quarry at Grinshill: view of the north face, showing the massive cross-bedded Helsby Sandstone Formation at the base, and the softer, more thinly bedded Tarporley Siltstone Formation above. (Photo: M. J. Benton.)
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Figure
3.44
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Sedimentary structures in the Grinshill quarries. (a) Lower portions of large-scale aeolian cross-beds in the Helsby Sandstone Formation. The section is about 10 m high. (b) Ripple marks on the surface of a fine-grained sandstone unit in the Tarporley Siltstone Formation. (Photos: M. J. Benton.)
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Figure
3.45
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Stratigraphical columns for the Triassic of central Nottinghamshire and for the southern North Sea. Based on Warrington et al. (1980), Cameron et al. (1992), and Johnson et al. (1994).
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Figure
3.46
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Cross-section through the Sherwood Sandstone Group and lower Mercia Mudstone Group, showing onshore deposits of eastern England around Derby, Nottingham, and Doncaster, and offshore in the Southern North Sea Basin. Based on Warrington (1974c) and Cameron et al. (1992).
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Figure
3.47
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Field sketches of the Triassic channel systems in the Nottingham Castle Formation at Styrrup Quarry, viewed roughly transverse to flow. Based on unpublished work by S. D. Burley.
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Figure
3.48
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Field sketches of the Triassic channel systems in the Nottingham Castle Formation at Scrooby Top Quarry. Major erosional bounding surfaces are shown in bold, and six successive bar systems are distinguished. Based on unpublished work by S. D. Burley.
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Figure
3.49
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Stratigraphical columns for the Triassic successions of the northern and southern Central Midlands regions of England. M, macrofossils; m, microfossils. (After Warrington et al., 1980, Charsley et al., 1990 and Barclay et al., 1997.)
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Figure
3.50
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Early Triassic palaeogeography of Central England, showing postulated major river systems, based on palaeocurrent measurements and studies of clast provenance. 1, Hulme Quarry; 2. Brockton Quarry; 3, Wollaston Ridge; 4, Claverley Road Cutting; 5, Burcot; 6, Shrewley. (After Wills, 1948.)
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Figure
3.51
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Sedimentary log recorded in the Hulme quarries, showing the five lithofacies in the succession of the Cannock Chase Formation. (After Steel and Thompson, 1983.)
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Figure
3.52
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Sedimentary log recorded at Brocton Quarry, showing the lithofacies A, B, C and E in the Cannock Chase Formation, as defined by Steel and Thompson (1983).
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Figure
3.53
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The Kidderminster Formation (KF) resting unconformably upon Bridgnorth Sandstone Formation (BSF) in Wollaston Ridge Quarry; (a) as seen in the 1930s, (b) an interpretive sketch. (After Whitehead and Pocock, 1947.)
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Figure
3.54
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The Claverley Road Cutting section through the Wildmoor Sandstone Formation, general view of the steep-sided cutting. (Photo: English Nature/Peter Wakely.)
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Figure
3.55
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The Burcot section (a) Bromsgrove sandstone overlying mudstones of the Wildmoor Sandstone (boundary marked with arrows) (b) Detail of the base of the sandstone body shown in (a) showing cross bedding. This is a distinct pebbly sandstone and it marks a major change from the red-brown sandstones and marls of the Wildmoor Sandstone Formation (Photo: English Nature/R. Cottle.)
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Figure
3.56
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The Shrewley canal cutting, showing the Arden Sandstone Formation of the Mercia Mudstone Group; red mudstones underlie the formation at the bottom right (arrowed). (Photo A13530 reproduced with permission, IPR/2226C, British Geological Survey, © NERC. All rights reserved.)
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Figure
3.57
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Comparative sections through the Arden Sandstone Formation at Shrewley, and at neighbouring sites. (After Old et al., 1991.)
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Figure
3.58
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The palaeogeography and sedimentary environments of South Wales in the Late Triassic Epoch: (a) sketch map showing the key localities, and the outcrop of major rock groups; (b) reconstructed palaeogeography of the area, showing uplands, a canyon and alluvial fan, major stream systems, shore-face platforms and screes, and the offshore giant playa; (c) cross-section, showing the shoreline features. All based on Tucker (1977, 1978).
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Figure
3.59
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Schematic cross-section through the Triassic succession of South Wales, showing the accumulation of sediments against the uplifted Carboniferous Limestone islands, until these were ovelapped during Penarth Group and Lias Group times. (After Wilson et al., 1990.)
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Figure
3.60
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Map of the coastal exposure of the Carboniferous and Triassic deposits at Sutton Flats, Ogmore-by-Sea. (After Thomas, 1968.)
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Figure
3.61
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Triassic clastic sediments overlying Carboniferous Limestone at Sutton Flats, Ogmore-by-Sea. (a) Irregular beds of Triassic conglomerate resting unconformably on steeply dipping Carboniferous Limestone. (b) Close-up of the lower portion of a poorly sorted Triassic conglomerate, showing incorporation of boulders of Carboniferous Limestone; field of view in (b) is about 5 m. (Photos: K. A. Kermack.)
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Figure
3.62
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Sketch map of the Barry Island outcrops of Triassic sediments overlying Carboniferous Limestone. (After Anderson, 1960.)
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Figure
3.63
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Horizontal sketch sections through the marginal facies on the west side of Barry Island, to show the relationship of the marginal facies to the Triassic platforms and the Carboniferous Limestone, at three points on the west side of Friars Point. (After Waters and Lawrence, 1987.)
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Figure
3.64
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Sedimentary log through the Late Triassic succession at Bendrick Rock, with the footprint horizon marked. (After Tucker and Burchette, 1977.)
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Figure
3.65
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A bedding plane on the foreshore at Bendrick, covered with three-toed dinosaur footprints, probably Anchisauripus and Grallator. Each small depression is a footprint. Width of the field of view is about 5 m. (Photo: M. J. Benton.)
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Figure
3.66
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Map of the track-bearing surface collected near Bendrick Rock, and currently on display in the National Museum of Wales. The rose diagram (inset) shows the predominant orientation of Grallator tracks. (After Lockley et al., 1996.)
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Figure
3.67
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The marginal Triassic sediments at Sully Island, showing the Carboniferous Limestone overlain unconformably by shore-zone clastic deposits, then replaced evaporites, and finally carbonates (see Figure 3.68). (Photo: M. J. Benton.)
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Figure
3.68
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Section at Sully Island, showing the main marginal playa facies (see Figure 3.67). (After Tucker, 1978.)
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Figure
3.69
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Thinly laminated cryptalgal limestones with nodular dolomites in the Sully Island succession. (Photo: M. J. Benton.)
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Figure
3.70
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Stratigraphical columns for the Triassic succession of Devon, showing the current, and the older nomenclature. M = macrofossils; m = microfossils. Based on Ussher (1875, 1876), Warrington et al. (1980), and Edwards and Scrivener (1999).
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Figure
3.71
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The lower part of the cliff at Budleigh Salterton, showing pebble beds and coarse sandstones in the lower part of the cliff, overlain by cavernous weathering Otter Sandstone Formation. The cliff is1520 m high. (Photo: M. J. Benton.)
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Figure
3.72
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Sedimentary features in the Budleigh Salterton coast section: (a) graphic sedimentary logs measured at three points through the Budleigh Salterton Pebble Beds (BSPB), and sketches of the upper and lower parts of the cliff section; (b) field relationships of the top of the BSPB, at the eastern end of the GCR section (SY 062 816). Based on Smith and Edwards (1991) and Wright et al. (1991) respectively.
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Figure
3.73
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Sedimentology of the Budleigh Salterton Pebble Beds. (a) Close-up view of rounded pebbles, partly imbricated, in large foresets; field of view about 1 m. (b) The top of the Budleigh Salterton Pebble Bed overlain by cavernous weathering sandstones of the Otter Sandstone Formation. The ventifact horizon underlies the light-coloured band at the base of the Otter Sandstone Formation, and is marked by the top of the hammer shaft. (Photos: P. Turner.)
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Figure
3.74
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Palaeogeography of the south of England during the deposition of the Budleigh Salterton Pebble Beds, showing the location of outcrops, and concealed occurrences detected by boreholes in Dorset and in the Hampshire Basin. Major palaeocurrent flow directions are indicated. Abbreviations: CF, Cranborne Fault; CFH, CranborneFordingbridge High; CSB, Central Somerset Basin; MH, Mendips High; PF, Pewsey Fault; PDF, Portadown Fault; WF, Wardour Fault; WG, Worcester Graben. (After Smith and Edwards, 1991.)
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Figure
3.75
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Map of the coastal outcrop of the Otter Sandstone Formation between Sidmouth and Budleigh Salterton, together with mean fluvial palaeoflow directions, and showing principal localities for fossil tetrapods. (From Benton et al., 1994.)
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Figure
3.76
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View of amalgamated channel sandstones at Ladram Bay, looking north-east towards the wooded ‘High Peak’ in background. (Photo: A. Newell.)
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Figure
4.1
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The historical (Richardson, 1911) and current (Warrington et al., 1980) lithostratigraphical terminology of the uppermost Triassiclowest Jurassic strata of south-west Britain. Chronostratigraphical units are shown at the right.
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Figure
4.2
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Two classic Penarth Group successions in southern England, on (a) the west Somerset coast, based on Lilstock and St Audries Bay, and (b) the south Devon coast, based on Culverhole and Charton Bay. (After Durrance and Laming, 1982.)
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Figure
4.3
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Palaeogeography of the British Isles during the Rhaetian Age. The classic sections in South Wales, Gloucestershire, Somerset, and Devon accumulated on marginal areas of the Welsh and Cornubian islands. The Langport Member is most fully developed in south. (After Poole, 1979.)
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Figure
4.4
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Cut sections through two basal ‘Rhaetic bone beds’, (ac) from Aust Cliff. In cut section (a), about 15 cm wide, the large rounded objects are clasts of Blue Anchor Formation. The smaller, dark objects between are phosphatic nodules, coprolites and rolled bone fragments. In (b), a surface view, the elongated black objects are probably ribs of marine reptiles, and the squarish element could be part of a limb bone. Smaller black objects are fish scales and teeth, and other lighter pieces are nodules. In (c) there is a vertical cut section of a large bone (top, centre). (Photos courtesy C.N. Trueman.) Figure 4.4contd. (d) Cut section through the basal ‘Rhaetic bone beds’ from Westbury Garden Cliff. The surface shows numerous well-preserved elongate bones of the small reptile Pachystropheus, showing weak current alignment. Other clasts include coprolites (e.g. immediately above the scale bar), some larger, abraded, bone fragments (far left, middle) and inorganic phosphate nodules. White patches of crystalline pyrite occur in association with the bones; the matrix is 70% disseminated pyrite. (Photo courtesy C.N. Trueman)
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Figure
4.5
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Map showing the locations of the 13 Penarth Group GCR sites: (1) Lavernock to Penarth*; (2) Stormy Down; (3) Wainlode Cliff*; (4) Westbury Garden Cliff*; (5) Aust Cliff*; (6) Hapsford Bridge; (7) Barnhill; (8) Wetmoor*; (9) Lulsgate; (10) St Audries Bay*; (11) Blue Anchor Point*; (12) Culverhole Point*; (13) Pinhay Bay. * Denotes that the site also exposes important Triassic red beds.
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Figure
4.6
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Section of the cliffs from Lavernock to Penarth, showing the occurrence of the Mercia Mudstone, Penarth, and Lias groups. (After Woodward, 1888.)
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Figure
4.7
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The Penarth Group, and underlying Mercia Mudstone Group, at Lavernock Point. (a) Overview of the cliffs and foreshore. The nearest face shows the Blue Anchor Formation of the Mercia Mudstone Group underlain by typical ‘red beds’ of the same group exposed in the core of a low anticline in the middle distance. To the north of this structure, the Penarth Group and lower beds of the overlying Lias Group occur in a shallow syncline. The town of Penarth is in the background to the right. (B) Cyclic units of sandstones, silty grey limestones and dark grey shales of the Westbury Formation, overlain by paler beds of the Lilstock Formation (arrowed). (Photos: Andrew Swift.)
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Figure
4.8
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Geological map of the LavernockSt Mary’s Well Bay district, showing the Mercia Mudstone Group, Penarth Group, and Lower Lias sediments. (After Trueman, 1920.)
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Figure
4.9
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The Penarth Group in Wainlode Cliff, looking upstream (northwards). (Photo: K. A. Kermack.)
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Figure
4.10
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Westbury Garden Cliff, looking downstream (westwards) showing loose blocks of phosphate-rich calcareous sandstone from the Westbury Formation Bone Bed on the shore, and Blue Anchor and Westbury formations in the cliff, the latter obscured by vegetation. (Photo: Andrew Swift.)
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Figure
4.11
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A slab of the basal bone bed from the Westbury Formation, Westbury Garden Cliff (Bristol City Museum, Geology Ce17770), containing a scatter of unabraded small bones from the aquatic reptile Pachystropheus, with some evidence of current alignment. A large, abraded plesiosaur epipodial (x) is at the left end. (After Storrs, 1994.)
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Figure
4.12
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Aust Cliff: view on the north-eastern side of the Severn Bridge, looking south-east. Red mudstones of the Mercia Mudstone Group form the lower two-thirds of the cliff, below the light coloured Blue Anchor Formation, above which lies the Penarth Group. Basal Lias Group beds lie at the very top, in the vegetation line. (Photo: Andrew Swift.)
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Figure
4.13
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Aust Cliff. (a) Geological map; (b) the broad anticlinal structure, and the succession of (1) red mudstones of the Mercia Mudstone Group, (2) the Blue Anchor Formation, (3) the Penarth Group, and (4) the Lias Group. (After Hamilton, 1977.)
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Figure
4.14
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Idealized sedimentary cycle in the Mercia Mudstone Group at Aust Cliff. (After Curtis, 1982.)
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Figure
4.15
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Gypsum deposits in the red mudstones of the Mercia Mudstone Group in the lower portions of the Aust Cliff section. (a) Deep V-shaped fissures filled with gypsum, perhaps forming parts of large-scale polygons. (b) Nodules and veins of gypsum. (Photos: M. J. Benton.)
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Figure
4.16
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Hapsford Bridge, view of the Penarth Group sediments, which rest unconformably on Carboniferous Limestone. (Photo: R. Cottle.)
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Figure
4.17
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Map of the Vallis Vale and Hapsford Bridge localities. Various exposures along the stream sides show progressive onlap of first the Penarth Group, then the Lower Lias, and finally the Inferior Oolite (Middle Jurassic) onto the Carboniferous Limestone Mendip island. (After Savage, 1977).
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Figure
4.18
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Perspective view of Barnhill Quarry, at the height of its operations in the 1930s, looking NNE. A, B, C, and D are Carboniferous Limestone platforms, and T(a), T(b), and T(c) are overthrusts. Penarth Group sediments rest unconformably on top of this stepped landscape. (After Reynolds, 1938.)
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Figure
4.19
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Wetmoor stream sections showing small exposures of Triassic sediments. (a) Mercia Mudstone Group mudstones, seen in the northern end of the western GCR area; (b) Cotham Member limestones and clays, and the Cotham Marble, which are overlain by basal Lias units, in the eastern GCR area. (Photos: R. Cottle.)
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Figure
4.20
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Lulsgate Quarry, view of the north face. This shows the steeply dipping Carboniferous Black Rock Limestone at the base, overlain unconformably by horizontal units of the Penarth Group. (Photo: D. Evans.)
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Figure
4.21
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The Penarth Group at St Audries Bay. (a) The west side of the bay. The Blue Anchor Formation is in the left foreground. The Penarth Group is in the left middle distance and below the Lias Group in the cliff in the background. The base of the Jurassic succession is at the foot of the headland. (b) View looking east from the Penarth Group exposure at beach level. The cliff consists largely of the Rydon Member (Blue Anchor Formation) overlain by the Williton Member. The Westbury Formation dips towards the right from the highest point in the cliff. (Photos: Andrew Swift.)
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Figure
4.22
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View of Blue Anchor Point, looking east, showing the anticlinal arrangement of the deposits at the far left, and multiple faults behind. (Photo: K. A. Kermack.)
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Figure
4.23
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Relationships of the various forms of gypsum at Blue Anchor Point. (a) Nodular alabaster in the laminated beds, with white veins parallel and cross-cutting pink veins. (b, c) Horizontal white veins cut by thin, pink veins and both deformed by subsequent movements. (After Hamilton and Whittaker, 1977.)
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Figure
4.24
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Detail of the multiple faults at Blue Anchor Point, disturbing the succession of Blue Anchor Formation (lower part of cliff) overlain by Westbury Formation at the top. A boulder of the latter, with the bone bed (arrowed), lies on the beach. (Photo: K. A. Kermack.)
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Figure
4.25
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The basal Westbury Formation bone bed (the Culverhole Bone Bed) infilling cracks and burrows in the eroded surface of the Blue Anchor Formation at Culverhole Point. (Photo: R. J. G. Savage.)
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Figure
4.26
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The Langport Member (LM) of the Penarth Group (paler beds) overlain by Lias Group (LG) at Pinhay Bay. (Photo: R. J. G. Savage.)
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Figure
4.27
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The Langport Member succession at Pinhay Bay. (a) Diagrammatic section. (b) Diagram of a section on the west side of Pinhay Bay, showing wedge bedding, rubbly limestones, and porcellanous selvages. (ce) Synsedimentary deformation of the Langport Member; (c) part of a folded limestone bed in the Slump Bed, the core of which has been plastically squeezed and tapers to a point; (d) minor contortions, including pseudo-ripple marks, near the base of the section; (e) part of a limestone bed within the Slump Bed that has been folded on itself. (a, after Swift, (1995); be, after Hallam, 1960.)
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Figure
4.28
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Sedimentary structures in the Langport Member at Pinhay Bay. (a) The ‘main’ slump bed, showing soft sediment deformation features caused by downslope movement of a semi-consolidated sediment (b) A thick resedimented limestone containing numerous pebbles derived from the break-up of earlier Langport Member beds. (Photos: Andrew Swift.)
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