Stephenson, D., Loughlin, S.C., Millward, D., Waters, C.N. & Williamson, I.T. 2003. Carboniferous and Permian Igneous Rocks of Great Britain North of the Variscan Front. Geological Conservation Review Series, No. 27, JNCC, Peterborough, ISBN 1 86107 497 2.

The original source material for these web pages has been made available by the JNCC under the Open Government Licence 3.0. Full details in the JNCC Open Data Policy

Figures and tables

Figures

(Figure 1.1) Map of the British Isles, showing the main outcrops of Carboniferous and Permian igneous rocks and the major tectonic features that existed during Carboniferous times. Based on published sources, including British Geological Survey (Tectonic map of Britain, Ireland and adjacent areas) (1996); Cameron and Stephenson (1985); Chadwick and Holliday (1991); Chadwick et al. (1995); Corfield et al. (1996); Francis (1982, 1991); Guion et al. (2000); Leeder (1974); Macdonald et al. (1981); Read (1988); Rippon et al. (1996); and Smythe et al. (1995). See (Figure 4.4) (Chapter 4) for outcrops in the northern Highlands.

(Figure 1.2) Stratigraphical distribution of British Carboniferous and Permian extrusive rocks (open bars) and intrusive rocks (solid bars). Timescale after Gradstein and Ogg (1996). See individual chapters for more detailed stratigraphical charts. (HBF = Highland Boundary Fault; SUF = Southern Upland Fault; SF = Stublick Fault; MF = Maryport Fault.)

(Figure 1.3) Continental dispositions in Late Devonian time (c. 380 Ma). Microcontinents including Avalonia and Armorica have collided with the margin of Laurentia, completing the assembly of the crust that now forms the British Isles. Gondwana lies to the south. The absolute positions of the continents on the globe at this time are still not known exactly, so the ocean between Laurentia and Gondwana may have been wider than is shown here. After McKerrow et al. (2000).

(Figure 1.4) Continental dispositions in Late Carboniferous time (c. 320 Ma). Gondwana has collided with Laurentia, creating the supercontinent of Pangaea, and the crust of the British Isles lies close to the equator. After McKerrow et al. (2000).

(Figure 1.5) Early Carboniferous tectonics of Europe. A fault-bounded wedge of northern Europe was moving eastwards, creating strike-slip movements along pre-existing lineaments. (GGF = Great Glen fault system; MVF = Midland Valley fault system; BNF = Brabant-North Sea fault system.) After Coward (1993).

(Figure 1.6) Late Carboniferous to Early Permian tectonics of Europe. Closure of the Ural Ocean led to the continental wedge being driven back to the west, reversing the directions of strike-slip movement. (GGF = Great Glen fault system; MVF = Midland Valley fault system; BNF = Brabant–North Sea fault system.) After Coward (1993).

(Figure 1.7) Range of compositions of Carboniferous and Permian igneous rocks, illustrated by a plot of Differentiation Index (normative % quartz + nephe-line + orthoclase + albite) against normative feldspar composition (% anorthite/(anorthite + albite)), as used in the classification of Coombs and Wilkinson (1969); and Macdonald (1975). (a) Dinantian igneous rocks of Scotland, after Smedley (1986a); (b) Silesian and Permian igneous rocks of Scotland, after Wallis (1989); (c) Silesian igneous rocks of the English Midlands, after Kirton (1984).

(Figure 1.8) Peridotite xenolith with a thin rim of altered chilled basalt in the Weaklaw Vent, North Berwick Coast GCR site. The coin is 24 mm in diameter. (Photo: B.G.J. Upton.)

(Figure 1.9) Xenoliths in an Early Permian olivine nephelinite dyke at Gribun, Isle of Mull; dark pyroxenites and pale-coloured granulite-facies gneisses. Note the folding in the large block of gneiss. The coin is 24 mm in diameter. (Photo: B.G.J. Upton, from Upton et al., 1998.)

(Figure 1.10) Generalized section through the upper continental lithosphere beneath the Midland Valley of Scotland. The left-hand column shows mean seismic velocities after Bamford (1979) and principal mineral assemblages (in brackets). (gt = garnet; ksp = potassium feldspar; mt = magnetite; of = olivine; pl = plagioclase; px = pyroxene; qz = quartz; sill = sillimanite; sp = spinel.) After Upton et al. (1984).

(Figure 2.1) Stratigraphical and geographical distribution of Dinantian volcanic rocks in and around the Midland Valley of Scotland. Note that the diagram attempts to show stratigraphical range and not thickness of volcanic successions. (ASVF = Arthur's Seat Volcanic Formation; BA = Barracks Ash; BF = Ballagan Formation; BHL = Burdiehouse Limestone; BHVF = Bathgate Hills Volcanic Formation; CA = Crosswood Ash; CG = Clackmannan Group; CHVM = Charles Hill Volcanic Member; CL = Carlops Lava; CPVF = Clyde Plateau Volcanic Formation; CSF = Clyde Sandstone Formation; GF = Gullane Formation; HUL = Hurlet Limestone; KF = Kinnesswood Formation; KRW = Kirkwood Formation; LF = Lawmuir Formation; LLF = Lower Limestone Formation; PEA = Port Edgar Ash; RH = Rashiehill Borehole; SDA = Seafield–Deans Ash; SVF = Salsburgh Volcanic Formation; WLOSF = West Lothian Oil-shale Formation (equivalent to the Aberlady

(Figure 2.2) Map of the Midland Valley showing the outcrops of Dinantian volcanic rocks and the major structural components. GCR sites: 1 = North Berwick Coast; 2 = Garleton Hills; 3 = Traprain Law; 4 = Arthur's Seat Volcano; 5 = Burntisland to Kinghorn Coast; 6 = Touch, Fintry and Gargunnock Hills; 7 = Campsie Fells; 8 = Dumbarton Rock; 9 = Dunrod Hill; 10 = Macrihanish Coast and South Kintyre; 11 = Heads of Ayr. After Cameron and Stephenson (1985).

(Figure 2.3) Map of the Kilpatrick Hills and Campsie Fells, showing outcrops of the Clyde Plateau Volcanic Formation and volcanotectonic lineaments defined by plugs, necks and proximal volcaniclastic beds. The most prominent lineament, along the north-west edge of the volcanic outcrops, is the Dumbarton–Fintry Line of Whyte and MacDonald (1974). Based on British Geological Survey 1:50 000 sheets 30W, Greenock (1990); 30E, Glasgow (1993); and 31W, Airdrie (1992).

(Figure 2.4) Correlation of composite sections in the Clyde Plateau Volcanic Formation. Based on information in Forsyth et al. (1996); Hall et al. (1998); and Paterson et al. (1990). N.B. formal designation of these units as members is currently in progress.

(Figure 2.5) Map of the area around the North Berwick Coast GCR site. (GH = Gin Head Vent; HS = Horseshoe Vent; L = The Lecks Vent; PC = Partan Craig Vent; QS = Quarrel Sands Vent; S = Scoughall Vent; ST = Seacliff Tower Vent; T = Tantallon Vent; W = Weaklaw Vent; YC = Yellow Craig Plantation Vent; YM = Yellow Man Vent.) After McAdam (in McAdam and Clarkson, 1986); and British Geological Survey 1:50 000 sheets 33W, Haddington (1985); and 33E, Dunbar (1986).

(Figure 2.6) Tantallon Castle, on agglomerate cliffs of the Tantallon Vent, North Berwick Coast GCR site, with the phonolitic trachyte plug of the Bass Rock beyond. (Photo: British Geological Survey, No. D3665, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 2.7) Basanite dyke (left) cutting vent agglomerate of the Yellow Man Vent, North Berwick Coast GCR site. The cliff is about 6 m high. (Photo: British Geological Survey, No. D1113, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.8) Basaltic bombs (rounded) and blocks (angular) in red, bedded basaltic tuffs at The Lecks, North Berwick Coast GCR site. The hammer head is about 15 cm long. (Photo: British Geological Survey, No. D3044, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.9) Mugearite lava at North Berwick, showing flow lamination in the main body of the flow and a slaggy, amygdaloidal flow top. The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. D3041, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.10) Map of the area around the Garleton Hills GCR site. Based on Geological Survey 1:10 560 mapping by M.F. Howells (1961) and A.D. McAdam (1964).

(Figure 2.11) Trap featuring in trachyte lavas, dipping to the right (south), modified by ice action and glacial drainage, at Kae Heughs, Garleton Hills. (Photo: British Geological Survey, No. D3262, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.12) Map of the area around the Traprain Law GCR site. Based on Geological Survey 1:10 560 mapping by M.F. Howells (1963–1964) and A.D. McAdam (1964–1967 and 1974–1976).

(Figure 2.13) Traprain Law from the south-east. The shape of the hill probably reflects the laccolithic form of the phonolite intrusion. (Photo: P MacDonald.)

(Figure 2.14) Map of the area around the Arthur's Seat Volcano. After Land and Cheeney (2000); and British Geological Survey 1:10 000 Sheet NT 27 SE (2000).

(Figure 2.15) Cross-section of the southern part of Holyrood Park, Edinburgh, passing through the Arthur's Seat Volcano. After Mitchell and Mykura (1962).

(Figure 2.16) Castle Rock from Princes Street Gardens, Edinburgh; a plug of olivine basalt within the Arthur's Seat Volcano GCR site. Note the glacial 'tail' to the left (east), protected by the plug. (Photo: British Geological Survey, No. MNS5624, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.17) General view across Calton Hill (old observatory and monument on the summit), towards the Arthur's Seat Volcano and the Salisbury Craigs Sill, Edinburgh. (Photo: P Macdonald.)

(Figure 2.18) Pyroclastic breccias, consisting of blocks of basalt in a matrix of red tuff, Lion's Haunch Vent, Arthur's Seat Volcano GCR site. The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. D3461, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 2.19) Spectacular columnar jointing of basalt in vent intrusion, Samson's Ribs, Arthur's Seat Volcano GCR site. (Photo: British Geological Survey, No. D3465, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.20) The analcime-dolerite sill of Salisbury Craigs, Arthur's Seat Volcano GCR site. (Photo: British Geological Survey, No. D5403, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 2.21) The volcanic succession exposed in the Burntisland to Kinghorn Coast GCR site.

(Figure 2.22) Basaltic pillows with hyaloclastite in the Kinghorn Volcanic Formation on the shore at Bellypuff, north-east of Kinghorn [NT 2740 8725]. (Photo: British Geological Survey, No. D5217, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 2.23) Map of the area around the Touch, Fintry and Gargunnock Hills GCR site. Based on Geological Survey 1:50 000 Sheet 39, Stirling (1970).

(Figure 2.24) Cross-section of the northern part of the Touch, Fintry and Gargunnock Hills GCR site showing the dominant lava-types and boundaries between members of the Clyde Plateau Volcanic Formation. After Francis et al. (1970).

(Figure 2.25) Trap-featuring on the northern escarpment of the Gargunnock Hills, around Carleetheran; Fintry Hills beyond. (Photo: P Macdonald.)

(Figure 2.26) Corrie of Balglass on the northern escarpment of the Campsie Fells, with the Fintry Hills in the background. Largely microporphyritic basalts and hawaiites of the Lower North Campsie Lava Member forming the steep wall of the corrie, overlie volcaniclastic rocks derived from the North Campsie Linear Vent System. (Photo: P Macdonald.)

(Figure 2.27) The western end of the Campsie Fells viewed across Strath Blane from the south-west. The Dumfoyne Vent is the feature in the centre of the photograph; the Dumgoyne Vent is to the left of it. The high ground on the skyline above Dumgoyne marks the south-west end of the North Campsie Linear Vent System. (Photo: J.G. MacDonald.)

(Figure 2.28) Map of the area around the Campsie Fells GCR site. Based on British Geological Survey 1:50 000 Sheet 30E, Glasgow (1993).

(Figure 2.29) Hawaiite lava at Jenny's Lum, western Campsie Fells. Note the flat-lying joints, particularly in the upper part of the flow, which are parallel to the flow texture of platy andesine microphenocrysts. The height of the cliff is over 15 m. (Photo: J.G. MacDonald.)

(Figure 2.30) Dumbarton Rock, a plug of olivine basalt, from the River Clyde. (Photo: J.G. MacDonald.)

(Figure 2.31) Map of the area around the Dumbarton Rock GCR site. After Whyte (1966).

(Figure 2.32) Diagrammatic cross-section illustrating possible structures associated with the Dumbarton Rock volcano. After Whyte (1966, fig. 4). where in the Clyde Plateau Volcanic Formation. They also occur in the Paleocene lava sequence of the Isle of Skye, where they are represented by the Roineval GCR site in the British Tertiary Volcanic Province GCR Volume (Emeleus and Gyopari, 1992).

(Figure 2.33) Map of the area around the Dunrod Hill GCR site. Based on British Geological Survey 1:10 000 Sheet NS 27 SW (1987).

(Figure 2.34) View from the north-west flank of Cauldron Hill, towards Gourock and the River Clyde. The low crag is typical of the composite hawaiitic lavas in the Dunrod Hill GCR site. (Photo: D. Stephenson.)

(Figure 2.35) Map of the area around the Machrihanish Coast and South Kintyre GCR site. Based on British Geological Survey 1:50 000 Provisional Series Sheet 12, Campbeltown (1996).

(Figure 2.36) Skerry Fell Fad, Macrihanish Coast and South Kintyre GCR site. The summit rocks are trachyte, either infilling an earlier valley feature or possibly forming a lava dome. Note the terracettes due to soil creep on the steep slopes below the summit. (Photo: C. Bond.)

(Figure 2.37) Geological map of the area around the Heads of Ayr GCR site. After Whyte (1964); and Lawson and Weedon (1992). Note the unconventional orientation of 2.37b (north at bottom) for easy comparison with (Figure 2.38).

(Figure 2.38) The West Cliff, at Heads of Ayr. Note the folded bedded tuffs within the Heads of Ayr Neck and the straight dykes on the wave-cut platform (compare with (Figure 2.37)b). (Photo: P Macdonald.)

(Figure 3.1) Map of the Solway, Northumberland and Tweed basins showing the outcrops of Dinantian volcanic rocks and the major structural components. GCR sites: 1 = Gill Beck; 2 = Bothel Craggs Quarry; 3 = Little Mel Fell Quarry; 4 = Langholm–Newcastleton Hills; 5 = Lintmill Railway Cutting; 6 = Hareheugh Craigs; 7 = Cottonshope Head Quarry; 8 = Kershope Bridge; 9 = River Esk, Glencartholm. (Volcanic units are as follows: B = Birrenswark Volcanic Formation; C = Cockermouth Lavas; Co = Cottonshope Basalts; G = Glencartholm Volcanic Beds; K = Kelso Lavas; Ke = Kershopefoot Lavas; MF = Mell Fell Vent.) Information from published sources including Chadwick and Holliday (1991); Chadwick et al. (1995); Leeder (1974); and British Geological Survey (Tectonic map of Britain, Ireland and adjacent areas, 1996).

(Figure 3.2) Stratigraphy of the volcanic rocks of the Solway, Northumberland and Tweed basins. The range of strata cut by intrusions and volcanic rocks is also shown. After Gawthorpe et al. (1989).

(Figure 3.3) Map of the area around the Gill Beck GCR site. Based on British Geological Survey 1:10 000 sheets NY 13 SE; and NY 13 SW (both 1991).

(Figure 3.4) An exposure of conglomerate, belonging to the Lower Carboniferous Basal Beds, below the base of the Cockermouth Lavas in Gill Beck. The hammer shaft is 40 cm long. (Photo: D. Stephenson.)

(Figure 3.5) Map of the area around the Bothel Craggs Quarry GCR site. Based on British Geological Survey 1:50 000 Sheet 23, Cockermouth (1997).

(Figure 3.6) Bothel Craggs Quarry, excavated in fresh tholeiitic andesite of the Cockermouth Lavas; view south towards the western fells of the Lake District. (Photo: D. Stephenson.)

(Figure 3.7) Map of the area around the Little Mell Fell Quarry GCR site. Based on British Geological Survey 1:10 000 Sheet NY 42 SW (2000).

(Figure 3.8) Lapilli-tuff from an inferred volcanic vent, possibly related to the Cockermouth Lavas, exposed on the hillside above the Little Mell Fell Quarry GCR site. (Photo: British Geological Survey, No. P505644, reproduced with the permission of the director, British Geological Survey, © NERC.)

(Figure 3.9) Map and cross-section of the area around the Langholm-Newcastleton Hills GCR site. Based on Geological Survey 1:63 360 Sheet 11, Langholm (1968).

(Figure 3.10) View from the bank of the Tarras Water, towards the slopes of Cloak Knowe in the Langholm–Newcastleton Hills GCR site. Lavas of the Birrenswark Volcanic Formation form the distinct feature with scattered exposures midway up the slope; the lower slopes are till covered, and river terraces occupy the foreground. (Photo: K.M. Goodenough.)

(Figure 3.11) Map of the area around the Lintmill Railway Cutting GCR site. Based on Geological Survey Old Series 1:63 360 Sheet 25, Galashiels (1879); geochemical sample points from Smedley (1986a).

(Figure 3.12) View east along the Lintmill Railway Cutting, with the Kelso Lavas exposed in the cutting on the left. (Photo: I.T. Williamson.)

(Figure 3.13) Map of the area around the Hareheugh Craigs GCR site. Based on Geological Survey Old Series 1:63 360 Sheet 25, Galashiels (1879).

(Figure 3.14) View from the south-west of Hareheugh Craigs; a plug-like intrusion of hawaiitic rocks within the Kelso Lavas. (Photo: C. MacFadyen.)

(Figure 3.15) Map of the area around the Cottonshope Head Quarry GCR site. Based on geological mapping by W. Anderson (1932, Geological Survey Archives).

(Figure 3.16) Map of the area around the Kershope Bridge GCR site. Based on Geological Survey 1:63 360 Sheet 11, Langholm (1968).

(Figure 3.17) Map of the area around the River Esk, Glencartholm GCR site. (HBF = Heck's Burn Fault; MF = Mumbie Fault.) Based on Geological Survey 1:10 560 Sheet NY 37 NE (1967).

(Figure 4.1) Range and distribution of the Silesian and Early Permian volcanic rocks of Scotland. After, in part, Cameron and Stephenson (1985).

(Figure 4.2) Map of central and southern Scotland showing the main outcrops of Silesian and Permian volcanic rocks. GCR sites: 1 = East Fife Coast; 2 = Howford Bridge; 3 = Carron Water; 4 = Ardrossan to Saltcoats Coast. Information from published sources, including Cameron and Stephenson (1985); Francis (1991); Read (1988); and Rippon et al. (1996).

(Figure 4.3) Map showing areas of outcrop, and thickness variations, of the Troon Volcanic Member. After Monro (1999); Geological Survey 1:50 000 sheets 14' Ayr (1978); 14E, Cumnock (1976); and British Geological Survey 1:50 000 Sheet 22E, Kilmarnock (1999).

(Figure 4.4) Map showing the location of plugs and vents of Carboniferous to Permian age in the Highlands. The Early Permian lavas of Glas Eilean are also indicated. After Rock (1983).

(Figure 4.5) Map of the south-east Fife coast, showing the distribution of volcanic necks. The named volcanic necks lie within the East Fife Coast GCR site. (Volcanic necks, from west to east: LL = Lundin Links; VF = Viewforth; RP = Ruddons Point; KC = Kincraig; CF = Craigforth; CN = Chapel Ness; EH = Elie Harbour; EN = Elie Ness; WL = Wadeslea; AR = Ardross; CH = Coalyard Hill; NW = Newark; DC = Dovecot; DR = Davie's Rock; SM = St Monance.) Based on Geological Survey 1:50 000 Sheet 41, North Berwick (1970).

(Figure 4.6) Schematic cross-section through an evolving tuff-ring, illustrating some of the volcanic processes thought to have been involved in the emplacement of the East Fife volcanic necks. The exposed necks within the GCR site may be interpreted in terms of sub-horizontal sections through this structure. (Features marked on the diagram: 1 = ring-faults with marginal tuffisite and breccia, or basaltic dykes; 2 = tuffisite within country rock — may develop adjacent to sills or dykes; 3 = large foundered bodies of country rock within vent and entrained within breccias and tuffisite; 4 = minor intrusions emplaced along bedding and fault planes.) Based on Forsyth and Chisholm (1977, fig. 17 after Francis, 1970b and Lorenz, 1973); Lorenz (1986); and Godchaux et al. (1992).

(Figure 4.7) Basaltic bomb showing impact effects in the underlying tuffs, Elie Ness Neck, East Fife Coast GCR site. The hammer head is about 15 cm long. (Photo: British Geological Survey, No. MNS1635, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 4.8) Flow-banding in tuffisite (below hammer) intruded into a large raft of sandstone (on which the hammer rests) in the north-eastern part of the Coalyard Hill Neck, East Fife Coast GCR site. The pale fragments elongated parallel to the edge of the sandstone are of bleached basalt. The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. D1680, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 4.9) Western margin of the St Monance Neck, East Fife Coast GCR site, showing tuff and agglomerate (right), upturned, disorientated sediments (top left) and a monchiquitic dyke emplaced along part of the margin (top centre). The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. D1679, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 4.10) Curved columnar jointing in basalt intrusion within the Kincraig Neck, East Fife Coast GCR site. (Photo: British Geological Survey, No. D1684, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 4.11) Map of the area around the Howford Bridge GCR site. Based on Geological Survey 1:10 560 sheets NS 52 NW (1966); and NS 52 SW (1964).

(Figure 4.12) Cliffs of the River Ayr near Howford Bridge, showing aeolian sandstones of the Mauchline Sandstone Formation, overlying poorly bedded tuffs of the Mauchline Volcanic Formation. (Photo: British Geological Survey, No. C2917, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 4.13) Map of the area around the Carron Water GCR site. Based on British Geological Survey 1:10 000 Sheet NS 80 SE (2000).

(Figure 4.14) Residual 'core' within heavily-weathered basalt lava of the Carron Basalt Formation on the west bank of the Carron Water GCR site. (Photo: K.M. Goodenough.)

(Figure 5.1) Map showing the main outcrops of alkali dolerite sills and dykes of Carboniferous and Early Permian age in central and southern Scotland. GCR sites: 1 = Arthur's Seat Volcano (Salisbury Craigs Sill); 2 = South Queensferry to Hound Point (Mons Hill Sill); 3 = Ardrossan to Saltcoats Coast; 4 = Lugar; 5 = Benbeoch; 6 = Craighead Quarry. The Dubh Loch GCR site lies outside the range of this map (see (Figure 5.2)). After Cameron and Stephenson (1985).

(Figure 5.2) Map showing the location and azimuth distribution of the main alkaline lamprophyre (camptonite and monchiquite) dyke-swarms of the northern Highlands. Azimuth distributions are presented as total percentage of dykes in each swarm with a particular orientation; thus long arms indicate swarms trending more uniformly than short ones. The number of dykes recorded in each swarm is shown in brackets. Isolated occurrences of monchiquite and camptonite are shown by M and C respectively. After Rock (1983).

(Figure 5.3) Map showing the components of the west and central Fife sill-complex, illustrating their close relationship with volcanic necks. Named sill components: C–C–B = Crombie–Cairneyhill–Bellknowes; C–C–G = Craigluscar–Cluny–Glenrothes; C–D–T = Cairnfolds–Dollar–Tillicoultry; D–S = Dunnygask–Steelend; F = Fordell; O–K–P = Oakley–Kinneddar–Parklands; P–C–K = Parkhill–Cowdenbeath–Kinglassie; T–K = Townhill–Kingseat; V–K = Valleyfield–Kinnell. After Francis and Walker (1987).

(Figure 5.4) Simplified diagram showing how large-volume multi-leaf sills were envisaged by Francis and Walker (1987) as having been fed from magma rising up volcanic pipes.

(Figure 5.5) A schematic diagram illustrating the effects of coal–magma interaction, as observed in the basic alkaline sills of Fife. After Walker and Francis (1987).

(Figure 5.6) Map of the area around the South Queensferry to Hound Point GCR site. After McAdam (in McAdam and Clarkson, 1986).

(Figure 5.7) Base of the Hound Point quartz-dolerite sill at Hound Point, forcing up the underlying beds of sandstone. The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. D1917, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 5.8) Basic sill intruding and transgressing sedimentary rocks of the West Lothian Oil-shale Formation and altered to 'white trap', South Queensferry shore. The hammer shaft is about 35 cm long. (Photo: A.D. McAdam.)

(Figure 5.9) Map of the area around the Ardrossan to Saltcoats Coast GCR site. After Bassett (in Bluck, 1973).

(Figure 5.10) The contact between the base of the Saltcoats Main Sill (pale weathering) and baked coal-bearing sedimentary rocks (dark). The sill has been altered to form 'white trap' adjacent to the coal. The hammer is 28 cm long. (Photo: C. MacFadyen.)

(Figure 5.11) Diagrammatic cross-section of the Saltcoats Main Sill below the bathing pool. After Patterson (1946).

(Figure 5.12) Map showing the outcrop of the Lugar Sill and the locations of boreholes through the sill. After Henderson and Gibb (1987).

(Figure 5.13) Cliff exposures of the picritic central part of the Lugar Sill in the Glenmuir Water, upstream from the railway viaduct, Lugar GCR site. (Photo: K.M. Goodenough.)

(Figure 5.14) Polished sample of pegmatitic kaersutite-augite-rich nepheline-gabbro or nephelinolite ('lugarite) from the Lugar Sill. Note the long acicular crystals of kaersutite, particularly well developed in the marginal zone, and smaller, more equidimensional augite. Grant Institute of Geology and Geophysics (University of Edinburgh) collection. (Photo: British Geological Survey, No. P505645, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 5.15) Correlation of borehole sections through the Lugar Sill. After Henderson and Gibb (1987). See (Figure 5.12) for locations.

(Figure 5.16) Variations of key major and trace elements in a vertical section through the Lugar Sill (Borehole 3). After Henderson and Gibb (1987). See text for details.

(Figure 5.17) Map of the area around the Benbeoch GCR site. Based on Geological Survey 1:10 560 Ayrshire sheets 67NW; and 66NE (both 1910); and 1:63 360 Sheet 14, Ayr (1933).

(Figure 5.18) Benbeoch Crags from the south-east. Note the strongly developed columnar jointing in the nepheline-dolerite of the Benbeoch Sill. The top of the sill has been removed by erosion and up to 12 m at the base is covered by scree and boulders, but a 40 m-thick section is exposed. (Photo: Scottish Natural Heritage.)

(Figure 5.19) Variation in modal olivine and augite through the Benbeoch Sill.

(Figure 5.20) Map of the area around the Craighead Quarry GCR site. Based on Geological Survey 1:63 360 Sheet 15, Sanquhar (1937); and original mapping and proton magnetometer survey by J.J. Doody and J.G. MacDonald (2000).

(Figure 5.21) (a) Curling Stone made of nepheline-gabbro ('essexite') from Craighead Quarry. Compare the texture with that seen in the photomicrograph (b). (b) Photomicrograph of nepheline-gabbro ('essexite') from Craighead Quarry. Ordinary light. The largest single phenocryst is 5 mm in diameter. (Photos: J.G. MacDonald.)

(Figure 5.22) The south-east face of Craighead Quarry. The nepheline-gabbro ('essexite') dyke, here about 24 m wide, is exposed in the centre of the photo and the margins of thermally metamorphosed greywacke stand out on either side of the dyke. (Photo: J.G. MacDonald.)

(Figure 5.23) Map of the area around the Dubh Loch GCR site, Isle of Colonsay. Based on British Geological Survey 1:50 000 Provisional Series Sheet 35, Colonsay (1996). The inset shows the location of the main map.

(Figure 5.24) Close-up view of the analcime monchiquite dyke at the Dubh Loch GCR site, showing xenoliths of pyroxenite (dull black) and biotite-rich ultramafic rock 'glimmerite' (glossy black) in addition to large megacrysts of biotite (black). The lens cap is about 50 mm in diameter. (Photo: M. Anderson.)

(Figure 6.1) Map of the Midland Valley and southern Highlands of Scotland, showing the distribution of the Late Carboniferous tholeiitic Midland Valley Sill-complex and the associated dyke-swarm. GCR sites: 1 = South Queensferry to Hound Point (see Chapter 5); 2 = North Queensferry Road Cuttings; 3 = Wallstale; 4 = Lomond Hills; 5 = Gloom Hill, Dollar; 6 = Mollinsburn Cuttings; 7 = Corsiehill Quarry. After Cameron and Stephenson (1985).

(Figure 6.2) Map of north-east England, showing the area intruded by the Late Carboniferous tholeiitic Whin Sill-complex and associated dyke subswarms. GCR sites: 8 = Upper Teesdale; 9 = Steel Rigg to Sewingshields Crags; 10 = Longhoughton Quarry; 11 = Cullernose Point to Castle Point; 12 = Budle Point to Harkess Rocks; 13 = Greenfoot Quarry; 14 = Holy Island; 15 = Wydon. (Key boreholes: Cr = Crook; Et = Ettersgill; Ha = Harton; Lh = Longhorseley; Lo = Longcleugh; Ro = Rookhope; Th = Throckley; WB = Whitley Bay; Wo = Woodland.) After Francis (1982); and Johnson and K.C. Dunham (2001).

(Figure 6.3) Diagram to illustrate the mechanism of intrusion of the Midland Valley Sill-complex and the Whin Sill-complex, suggested by Francis (1982). (a) dykes are intruded to 0.5–1.0 km below the surface; (b) lateral intrusion of magma leads to gravitational flow down-dip and accumulation of magma at the bottom of the sedimentary basin; (c) to achieve hydrostatic equilibrium, magma advances up-dip on the other side of the basin, with en échelon fingering at the leading edge. Broken lines indicate variation inherent in multiple dyke sources.

(Figure 6.4) View from the air over Stirling. Outcrops of the SE-dipping Stirling Sill (Midland Valley Sill-complex) can be picked out by the tree-covered scarps that bound the golf course in the bottom right, Stirling Castle in the middle distance, and Abbey Craig (topped by the Wallace Monument) beyond. The Ochil Fault, which has fault-intrusions related to the sill-complex (e.g. the Gloom Hill GCR site) is responsible for the prominent south-facing scarp of the Ochil Hills in the distance. (Photo: British Geological Survey, No. D1940, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 6.5) Simplified stratigraphical column showing the lithostratigraphy of Carboniferous rocks cut by the Stephanian tholeiitic sills and dykes of Scotland and northern England. In northern England, the Liddesdale Group is found in the Northumberland Basin whilst the Alston Group occurs on the Alston Block. The inset shows the position of major limestone bands that are transgressed by the Whin Sill-complex. After Browne et al. (1996); Chadwick et al. (1995); and Johnson (1997).

(Figure 6.6) Hadrian's Wall capping north-facing crags of the Great Whin Sill at Housesteads, Northumberland. (Photo: British Geological Survey, No. L1512, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 6.7) Variation in the rank of coals close to three leaves of the Whin Sill-complex in the Harton Borehole, Durham. After Jones and Cooper (1970).

(Figure 6.8) Map of the area around the North Queensferry Road Cuttings GCR site. Based on Geological Survey 1:10 560 Sheet NT 18 SW (1966).

(Figure 6.9) Quartz-dolerite of the Midland Valley Sill-complex at North Queensferry, showing spheroidal weathering. The hammer shaft (bottom left) is about 35 cm long. (Photo: British Geological Survey, No. D2580, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 6.10) Map of the Midland Valley Sill-complex in the area around the Wallstale GCR site. After Read and Wilson (1959).

(Figure 6.11) Quartz-dolerite of the Midland Valley Sill-complex with strong vertical joints in Cambusbarron Quarry, Wallstale GCR site. The quarry face is 25–27 m high. (Photo: K.M. Goodenough.)

(Figure 6.12) Pale-coloured felsic segregation vein cutting quartz-dolerite in Murrayshall Quarry Wallstale GCR site. The lens cap is 50 mm in diameter. (Photo: K.M. Goodenough.)

(Figure 6.13) Map of the Midland Valley Sill-complex in the Lomond Hills. Based on Geological Survey 1:63 360 Sheet 40, Kinross (1971); and British Geological Survey 1:50 000 Sheet 40E, Kirkaldy (1999).

(Figure 6.14) The escarpment formed by the Midland Valley Sill-complex on the north-west side of the Lomond Hills, with the basanitic plugs of West Lomond (nearest) and East Lomond (in the distance) protruding above the level of the sill. (Photo: P Macdonald.)

(Figure 6.15) The base of the Lomond Hills quartz-dolerite sill in Craigmead Quarry. The contact, the underlying sedimentary rocks and a further thin sheet of dolerite are exposed in the shaded area to the right of the figure. (Photo: K.M. Goodenough.)

(Figure 6.16) Map of the area around the Gloom Hill GCR site. After Rippon et al. (1996).

(Figure 6.17) View towards the east of the exposures of the Ochil Fault-intrusion in the quarry at Gloom Hill, with Siluro-Devonian lavas on the left, quartz-dolerite of the fault-intrusion on the right, and the contact parallel to the quarry face. (Photo: I.T. Williamson.)

(Figure 6.18) Map of the area around the Mollinsburn Cuttings GCR site. Based on British Geological Survey 1:10 000 Sheet NS 77 SW (1987).

(Figure 6.19) E–W-trending quartz-dolerite dyke exhibiting good horizontal columnar jointing at Mollin Craig, Mollinsburn Cuttings GCR site. (Photo: C. MacFadyen.)

(Figure 6.20) Map of the tholeiitic basalt dyke exposed in the Corsiehill Quarry GCR site. Adapted from an interpretive handout prepared by the Countryside Ranger Service, Perth and Kinross District Council (1990).

(Figure 6.21) Map of the outcrops of the Great Whin Sill in the Upper Teesdale area. Based on Geological Survey 1:50 000 sheets 25, Alston (1965); and 31, Brough-under-Stainmore (1974).

(Figure 6.22) Quartz-dolerite of the Great Whin Sill (upper half of the cliff) at High Force, Upper Teesdale. The two highest layers of massive rock are dolerite, separated by a thin raft of baked sedimentary rock forming a plane of weakness near the top of the waterfall. Beneath is a thick bed of baked sandstone, resting upon well-bedded mudstones and limestones of the Tyne Bottom Limestone in the lower half of the cliff. (Photo: British Geological Survey, No. LFP00382, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 6.23) The Great Whin Sill exhibiting large-scale columnar jointing at Cauldron Snout, Upper Teesdale. (Photo: D. Stephenson.)

(Figure 6.24) Map of the area around the Steel Rigg to Sewingshields Crags GCR site. (BWL = Bath-house Wood Limestone, SPL = Single Post Limestone, SWL = Shotto Wood Limestone.) After Johnson (1959).

(Figure 6.25) View of the north-facing crags of the Great Whin Sill from Steel Rigg. Peel Crag (nearest to camera), Crag Lough and Sewingshields Crags in the distance, are all topped by Hadrian's Wall. (Photo: British Geological Survey, No. L1555, reproduced with the permission of the Director, British Geological Survey, NERC.)

(Figure 6.26) Map of the area around the Longhoughton Quarry GCR site. Based on Geological Survey 1:10 560 Sheet Northumberland 29SE (1926).

(Figure 6.27) Map of the area around the Cullernose Point to Castle Point GCR site. Based on Geological Survey 1:63 360 Sheet 6, Alnwick (1930).

(Figure 6.28) Columnar-jointed quartz-dolerite of the Great Whin Sill overlying sandstone at Castle Point. (Photo: British Geological Survey, No. A3077, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 6.29) Columnar-jointed quartz-dolerite of the Great Whin Sill at Cullemose Point. The sill, like the underlying sedimentary rocks in the foreground, is gently folded, as is well illustrated by the columns perpendicular to its margin. (Photo: British Geological Survey, No. A3079, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 6.30) Map of the area around the Budle Point to Harkess Rocks GCR site. Based on Geological Survey 1:10 560 Sheet Northumberland, Old Series 16NE (1899).

(Figure 6.31) Bamburgh Castle, sited on a crag of quartz-dolerite of the Great Whin Sill, viewed from Harkess Rocks. The flat rocks in the foreground are close to the top surface of the sill; overlying sedimentary rocks have been removed completely, but the chilled margin of the sill is preserved as a thin skin in places. (Photo: D. Stephenson.)

(Figure 6.32) Map of the area around the Greenfoot Quarry GCR site. After A.G. Dunham and Kaye (1965).

(Figure 6.33) Map of the Holy Island GCR site. After Goulty et al. (2000).

(Figure 6.34) Sketch of a south–north section through the centre of Castle Hill, Holy Island, showing the alternating dyke-like and sill-like sectors of the intrusion. After Goulty et al. (2000).

(Figure 6.35) The south coast of Holy Island, clearly showing the overall apparent dyke-like nature of the quartz-dolerite intrusion, which provides the site for the castle in the far distance and shelters the priory in the middle distance. St Cuthbert's Isle, in the foreground, is formed from a sill-like step in the intrusion. (Photo: P MacDonald.)

(Figure 6.36) Ropy flow structure on the lower inner surface of a large flattened amygdaloidal cavity (the amygdaloidal 'fill' having been eroded away), St Cuthbert's Isle, Holy Island GCR site. The lens cap is 50 mm in diameter. (Photo: D. Stephenson.)

(Figure 6.37) Map of the area around the Wydon GCR site. Based on Geological Survey 1:10 560 Sheet Northumberland, New Series 89SW (1926).

(Figure 6.38) The Haltwhistle Dyke, cutting sandstones and overlain by till, on the bank of the River South Tyne near Wydon. (Photo: British Geological Survey, No. A4129, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 7.1) Map of central England and the Welsh Borderlands showing locations of Carboniferous igneous rocks and the GCR sites. GCR sites: 1 = Litton Mill Railway Cutting; 2 = Water Swallows Quarry; 3 = Tideswell Dale; 4 = Calton Hill; 5 = Clee Hill Quarries 6 = Barrow Hill; 7 = Middle Hope; 8 = Spring Cove; 9 = Golden Hill Quarry. Based on Geological Survey 1:625 000 Geological map of the UK South (1979).

(Figure 7.2) Approximate ages and stratigraphical distribution of selected igneous rocks from central England and the Welsh Borderlands. The GCR sites are numbered as for (Figure 7.1). (Ba = Bartestree Dyke; Br = Brockhill Dyke; Ll = Llanllywel Monchiquite Dyke; LWL = Little Wenlock Lavas.) After Francis (1970a); and Kirton (1984). The timescale is that of Gradstein and Ogg (1996).

(Figure 7.3) Map of the Buxton-Tideswell area, Derbyshire, showing the outcrops of Carboniferous igneous rocks and the positions of the GCR sites (numbered as in (Figure 7.1)). Based on Geological Survey 1:50 000 sheets 99, Chapel en le Frith (1975); and 111, Buxton (1978).

(Figure 7.4) Map of the area around the Litton Mill Railway Cutting GCR site and horizontal section. After Walkden (1977).

(Figure 7.5) Litton Mill Railway Cutting viewed towards the south-east and showing the Upper Miller's Dale Lava (bottom right), overlain by well-bedded limestones of the Monsal Dale Limestones (above the inclined grassy ledge and reinforcing wall). The cutting is here about 18 m deep; see hammer, bottom right. A sketch of this view, with annotation, was presented by Cope (1933, fig. 5). (Photo: British Geological Survey, No. L2270, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 7.6) Map of Water Swallows Quarry. Based on Geological Survey 1:10 560 sheets SK 07 SE (1968); and SK 07 NE (1959).

(Figure 7.7) Columnar cooling joints developed in the dolerite of the Water Swallows Sill, taken in 1969. The section is probably about 20 m high, the base of the 24 m-thick sill being just below the quarry floor. Descriptions from this period indicate that the base of the sill is highly irregular and this may be the reason for the change in inclination of the joints from vertical in the lower tier, presumably above a horizontal base, to inclined away from the camera in the middle tier, where the base may be transgressing upwards. (Photo: British Geological Survey, No. L239, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 7.8) Map of the Tideswell Dale GCR site. Based on Geological Survey 1:10 560 Sheet SK 17 SE (1972).

(Figure 7.9) Temporary exposure (July 2002) at the base of the Tideswell Dale Sill, on the east side of Tideswell Dale (Location B on (Figure 7.8)). The sill forms the massive natural exposures at the top of the picture and is underlain by altered basalt lava in the centre. Beneath this is a red clay with sigmoidal prismatic joints that is interpreted as a thoroughly altered lava. See text for further discussion. The cutting is 0.8 m deep. (Photo: M. Murphy.)

(Figure 7.10) Map of the Calton Hill GCR Site. Based on Geological Survey 1:10 560 Sheet SK 17 SW (1972).

(Figure 7.11) Photomicrograph of a lherzolite nodule from Calton Hill (BGS thin section No. E8340) with coarse-grained olivine, only serpentinized along fractures, subordinate orthopyroxene (Opx) and clinopyroxene (Cpx). The contact with the host basalt (bottom) is very sharp with hardly any visible reaction. Plane-polarized light. The scale bar (top right) is 1 mm. (Photo: British Geological Survey, No. MN39854, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 7.12) Map of the Clee Hill Quarries GCR Site. Based on British Geological Survey 1:10 000 mapping by W. Barclay (1997).

(Figure 7.13) Columnar-jointed dolerite in a quarry at Clee Hills (probably Incline Quarry), taken in 1933. The section is about 25 m high, including about 6 m of baked mudstones and sandstones of the Coal Measures overlying the sill. (Photo: British Geological Survey, No. A6226, reproduced with the permission of the Director, British Geological Survey, O NERC.)

(Figure 7.14) Map of the Barrow Hill GCR Site. After Glover et al. (1993); and British Geological Survey 1:10 000 Sheet SO 98 NE (1989). Cross-section from Marshall (1946).

(Figure 7.15) Photomicrograph showing details of a tuffisite vein cutting through mudstones, from Tansey Green Clay Pit, Barrow Hill. Grain alignment occurs parallel with the vein and grain size decreases toward the vein margin. Plane-polarized light. (Photo: from Glover et al., 1993.)

(Figure 7.16) (a) Map of the Middle Hope peninsula illustrating the position of localities referred to in the text (1 = Swallow Cliff [ST 3245 6605]; 2 = 700 m WNW of Woodspring Priory [ST 337 664]). (b) Schematic model of the volcanic high responsible for the formation of the Middle Hope Volcanic Beds (FWB = fair-weather wave base; SWB = storm-wave base). Modified after Faulkner (1989b).

(Figure 7.17) Generalized sedimentary log of the Lower Carboniferous succession at the Middle Hope GCR site. The vertical scale is non-linear; figures are metres above base of section. Horizontal scale indicates grain size: (m = mudstone; s = siltstone; st = sandstone; c = conglomerate; M = mudstone (calcareous); W = wackestone; P = packstone; G = grainstone). After Faulkner (1989b).

(Figure 7.18) Graded lapilli-tuffs in the Middle Hope Volcanic Beds. The hammer shaft is about 35 cm long. (Photo: P.J. Cossey.)

(Figure 7.19) Graded and cross-bedded lapilli-tuffs, interbedded with limestones in the Middle Hope Volcanic Beds. The hammer shaft is about 35 cm long. (Photo: P.J. Cossey.)

(Figure 7.20) Map of the Spring Cove GCR Site. After Whittaker and Green (1983).

(Figure 7.21) Basaltic pillow lava at the Spring Cove GCR site with clasts of altered limestone and numerous calcite veins [ST 309 625]. The hammer shaft is about 35 cm long. (Photo: British Geological Survey, No. A11792, reproduced with the permission of the Director, British Geological Survey, © NERC.)

(Figure 7.22) Map of the Golden Hill Quarry GCR site. Based on Geological Survey 1:50 000 Sheet 250, Chepstow (1972).

(Figure 7.23) Schematic representation of the diatreme pipe, sub-diatreme monchiquite dyke and stratigraphical relationships at the Golden Hill Quarry GCR site. After D.T. Moffat (unpublished manuscript).

(Figure 7.24) Clinopyroxene megacryst in monchiquite from the Golden Hill Quarry. The crystal is 4 mm across. Crossed polars. (Photo: R.E. Bevins.)

(Figure G1) The classification of fine-grained felsic and mafic crystalline igneous rocks, based upon their felsic mineral content. The distinction between basalt and andesite and between trachybasalt and trachyandesite is based on the composition of the plagioclase feldspar present. For divisions of the trachyandesite + trachybasalt fields, see Figure G5b.

(Figure G2) The classification of coarse-grained felsic and mafic crystalline igneous rocks, based upon their felsic mineral content. The distinction between gabbroic rocks and diorite is based upon the composition of the plagioclase feldspar present. Medium-grained rocks are named by attaching the prefix 'micro', for example microsyenite. However, in this volume and commonly elsewhere, dolerite is used as a synonym for micro-gabbro.

(Figure G3) The more detailed classification of coarse-grained mafic crystalline igneous rocks, falling in the gabbroic rocks field of Figure G2, based upon their plagioclase, olivine and clinopyroxene content. Note that other varieties of gabbroic rock, containing orthopyroxene, do not occur in this essentially alkaline igneous province, except as lower crustal xenoliths (see Chapter 1).

(Figure G4) The classification of coarse-grained crystalline ultramafic rocks, based upon their olivine, orthopyroxene and clinopyroxene content.

(Figure G5) The most usual chemical classification of fine-grained crystalline igneous rocks (e.g. Le Maitre, 2002), used when it is not possible to classify according to their mineralogy due to very fine grain size. Note that alteration can result in the loss or addition of highly mobile elements such as sodium (Na) and potassium (K), with consequent changes in silica (SiO2) and inaccuracies in classification. (a) Total alkalis (Na2O + K2O) versus silica (SiO2). (b) Rocks in the shaded area of (a) can be subdivided according to their Na2O/K2O ratio. However, most Dinantian igneous rocks of Great Britain fall close to the dividing line between sodic and potassic affinities and hence are difficult to classify. In much of the older literature (before c. 1975), without the benefit of analyses, the terms 'trachybasalf and 'trachyandesite are commonly used in a general sense for both sodic and potassic types.

(Figure G6) The classification of fine-grained crystalline igneous rocks that is most commonly used in geo-chemical studies of Carboniferous and Permian igneous rocks of Great Britain. Modified by Macdonald (1975) after Coombs and Wilkinson (1969).

Tables

(Table 1.1) Carboniferous–Permian Igneous Rocks Block: GCR networks and site selection criteria.

(Table 2.1) Succession of the Clyde Plateau Volcanic Formation in the northern part of the Touch, Fintry and Gargunnock hills. (After Francis et al., 1970, table 7.)

(Table 2.2) Succession of the Clyde Plateau Volcanic Formation in the western Campsie Fells. (After Hall et al., 1998. table 4)

(Table 4.1) Lithological units and features of the volcanic necks between Lundin Links and St Monance, East Fife Coast.

(Table 4.2) Distribution of accidental xenoliths and megacrysts in the East Fife necks.

(Table G1) Local nomenclature of basic igneous rocks of Carboniferous and Permian age in Scotland, as used on Geological Survey maps and in most literature since 1928. Now being replaced by more-standard terminology based on dominant phenocrysts and, where possible, the chemical composition. (pl = plagioclase, ol = olivine, cpx = clinopyroxene, fetiox = iron-titanium oxides.)

References