Index

Page numbers in italic type refer to pages on which illustrations or tables appear. accretion amphibolites 191 at divergent plate boundaries 45-6 analcime 278, 296, 299 incipient, of oceanic 325 analcite 70-7 lower crustal igneous material 4, 5, 8 anatectic melts 306 N-S boundary zone, Iceland 151-2 andalusite 256 accretion model, formation 95 andesine 124 accumulation rates, Faeroese pile 234--5 andesite 448 acoustic basement 137 basaltic 79, 80, 186, 339, 438 Jan Mayen Ridge 87 peraluminous 65 acoustic basement reflectors 49, 51, 90 tholeiitic 163,445 comprising extrusive 50 Angmagssalik-Scoresby Sund, igneous activity 436 acoustic impedance zone 65 ankaramite 163, 203, 438 actinolite 125 tholeiitic 166 Aegir Ridge 157 anorthite 257 fan-shaped anomaly pattern 158 anorthoclase 412 fan-shaped spreading pattern 85 Anton Dohrn seamount 429 aegirine 376, 409, 411,414, 417 Antrim lava succession 343-4 indicating peralkine parental 416 Antrim Plateau titaniferous 411,412,416 flood basalts 217 aegirine-augite 78 persistent volcanism 445 aegirine 442 tholeiitic magmatism 446 aenigmatite 411 apatite 441 aeromagnetic anomalies 316 acicular 197 Iceland 147-9 apatite saturation 170 Africa/Europe convergence 30 Apectodinium homomorphum 266 African plate 29 Apectodinium hyperacanthuminformal zone 265, 399 agate 78 ~~ step heating dating 337, 339, 344, 357, 446 agglomerate 365, 366, 373,374, 436 36Ar initialization 203 silicic 376 Ardnamurchan aggregates, glomerophyric 78, 301 K-Ar dating 342 agpaites 447 silicic pyroclastic rocks 371-2 airfall deposits, pyroclastic 320, 325 Tertiary igneous rocks 341-2 albitization 70 Ardnamurchan igneous centre/central intrusive Alisocysta margarita informal zone 265 (volcanic) complex 365,386, 387, 444 Aliuarssik granite 210 Ardnamurchan-Mull, persistent volcanism 445 allivalite 391 Areosphaeridium diktyoplokus 400 Allt Coire Forsaidh, Skye, pyroclastic breccia 367 arfvedsonite 207,376,409 Allt nan Suidheachan, Skye 367 argillification 259 Alpine Orogeny 25 argon and the Rhine Graben 27, 29 closure of rocks to 340-1 Alpine Range, isostatic uplift 27 extraneous 204, 205, 306 alteration 78, 151,245, 257, 295, 299, 300, 305, 367 a complicating factor 203 , chloritic 205 contamination with 203 ! deuteric 217,219 problems with 211 of glass 275-6 inherited 343 hydrothermal 80, 186, 339, 365,440 radiogenic 218,258 hydrous 256, 258 argon diffusion 218 incipient, volcaniclastic sand 409 argon excess 305 interaction with seawater 125, 301 argon loss 217, 258, 312 metamorphic 186 diffusive 343 to smectitic 408 discrepancy 259 beds 76-7,78 result of alteration 203, 305 alteration products, Upper Series , V~ring systematic 331 Plateau 70 variable 205, 337 Amdrups Pynt (Nugalik), E Greenland 210 argon migration 255 amphibole 205, 207,210, 257 argon recoil problems 255, 258,260 brown 256 argon release 305 amphibolite facies 190 Arran: 455 456 Index

Arran (cont.) asthenospheric flow 19, 20 Central Ring Complex 373 asthenosphericupwelling 45, 330 central volcanic complex 444 Atlantic evolution, age constraints on 201-12 igneous centre 365 Atlantic plate 8 silicicpyroclasticrocks 373 augite 124, 128, 163, 165, 197, 257 Arran and Ailsa Craig 343,346 poikilitic 316 Arran dyke swarm 385 autobrecciation 374 ash bands 322 water-lain 312 ash clouds 78 ash deposits, British Tertiary Volcanic Province 365 Baffin Bay, igneous activity 431-4 ash horizons/layers 90, 141,430, 447 Baffin Bay spreading centre 434 airfall, graded 408-11 Balder Formation(s) 253,254, 255, 260, 261,266-7, Danish 413 280, 400, 407,408 derived from Faeroe-Greenland Province 411- ash marker horizon 325 12 ash marker seismic reflector 412 argillized 397, 403,409 deposition of 331 basaltic 413 pyroclastic activity 265 bentonitic 409, 414 tufts 77, 78 Denmark 395,397-403 Barents Sea margin 50, 423 Limfjord area 401-2 Barents Sea margin (western) negative series 397 early Tertiary volcanism 135-45 positive series 397, 412 geology 135-7 down-wind fallout, British Tertiary Volcanic rifted margin, evolution of 144-5 Province explosive eruptions 445 Tertiary sedimentation and deformation, SW Fe-Ti tholeiite composition 409, 411 Barents Sea and Svalbard 141-2, 144 late Palaeocene-early 445 volcanism at the Bjanaya marginal high 137, 141, Lower Tertiary strata 445 143 NorthSea 10,446 Barents Sea Platform 421 airfall, graded 409-14 Barents Shelf peralkaline composition 409 two major drainage systems 423-5 Thanet Beds, Lower Tertiary 376 western, Tertiary tectonics and sedimentation Upper Palaeocene 325 421-5 volcanic 395 Barra Volcanic Ridge System 325 ash 54, 119, 130, 132, 186, 257, 293, 315, 316, 342, basaltic 260 368,438, 442 basic primary 253 alkali 197, 233,295,445,447 peralkaline 411 alkali 432, 446 primary 255 altered 163,298 pyroclastic 407 Antrim 361 rhyolitic 411 aphyric 432 subalkaline rhyolitic 447 Baffin Island, dating of 433 tholeiitic 411 basanitic 435 Fe-Ti-rich 447 depleted 125, 127 vitric 255 dipping reflectors 5 volcanic, W Shetland Islands 263 early, fissure-fed 442 ash marker 141 early Palaeogene 130 Balder Formation 325 early Tertiary 123, 124, 225,271 North Sea 260, 442 E Greenland 111,203-4, 266 top Palaeocene 229,234 extrusion of 211 ash marker sequence 254 effect of alteration 148 ash sequence, correlation of Fur Formation, North Sea extrusive 7, 50 and NE Atlantic proposed 400 Faeroe Islands, chemicalgroups 230, 233 ashfall see ash Faeroe Rise 233 assimilation-fractionation model 362 -phyric 374 asthenosphere flow basalts 51 advection of heat by upward migration of partial glomerophyric 124 melt 11 high-Ti 232 high pressure of, N Atlantic 20 low in Si02 246 hot 3, 8, 9-10, 10-11, 16-17, 44, 45, 111,130 Iow-Ti 232 lateral density variations in 18-19 mid-Atlantic ridge 246, 301 and partial melting 8-10 Mikis-type 170 reduced temperatures 11 olivine 339,343, 344 rising 120 altered 374 Index 457

olivine-microphyric 299 Biscay margin 5, 6-7, 10 olivine-phyric 229, 230, 295 bivalves 278 picrite 177 BjornoyBasin 135, 137, 141,144, 145,421 plagioclase-phyric 124,229, 230, 277,432 Tertiary sediment distribution 141 primitive 433 Bjornoya marginal high 135, 144 quartz basalt 435 postvolcanic vertical movement 137 quartztholeiite, microphyric 435 volcanism 137, 141,143 silica-oversaturated 446 Bjornoya Trough 423-5 subaerial 295, 298-9 Bjornoya-Sorkapp fault zone 144 Tertiary, Wyville-Thomson Ridge and black shale facies 306~ Shelf 271-80 Blackstones Bank 345 tholeiitic 51,118, I6I, 197, 233,235,343,431-2, Blackstones Complex 429 445,447 Blind Rock Dyke, Donegal 344 formation of cycles, Prinsen af Wales Bjerge block faulting 325 (PWB) 197-9 Blosseville Group 437 olivine-rich 432 rapid accumulation 438 within plate 297, 305 Blosseville Group basalts 203 basalt genesis and formation of passive margin SW of BlossevilleKyst 181,187,436 130-2 basalts, K-Ar ages of and extrusion of 211 basalt lava terrains, Upper Tertiary, Iceland 152 main intrusive centres 202 basaltic differentiates, contaminated 355,356, 357 MORB-type mantle source 182 basaltic melt, Rhum 391 uplift of 21, 22 basanites 436 boreholes 85/58, 85/7 and 85/2B 271-80 baselap 102, 103, 112 Borgtinderne nepheline syenite intrusion 207, 210, dipping reflectors 100 211 basement boundary fault system, W Greenland 433 acoustic 137 breccia 368,436 reflectors 49, 50, 51, 90 crush 374 acoustically opaque I00, 110 explosion 365,369 basaltic (Faeroe islands) 115 hyaloclastite 430 continental metamorphic 226 slope-foot 287 gneiss 181 interbedded 370 opaque, oceanic 90 picritic 433 Precambrian 443 pillow 432 basement elevation 135 pyroclastic 365, 367, 369,370-1,372, 374 basement escarpments, Norwegian-Greenland Sea unbedded 368 43 volcanic 435 basement outcrops, seabed, Faeroe region 226 breccia zone, basal 80 basement rocks, Kangerdlugssuaq area, analysed Brendan Igneous Centre 312, 319, 322, 330, 331 190 emplacement of 322 basement trends, Porcupine Basin 331 late igneous activity 325 basin formation and sedimentation 434 Britain, igneous activity 443-6 basin inversion 25 British Tertiary Igneous Province 25, 80, 217,265-6, basin margin erosion 272 276, 338, 361 basin subsidence 118,432, 435, 445 dating problems 337 basins magmatic affinities 376 fault-controlled 386 regional setting 376-7 Mesozoic 25 relationship to opening of Atlantic 27 pre-opening, Norwegian-GreenlandSea 51-2 time and duration of activity 337-46 rifted 330 Ardnamurchan 341-2 sedimentary 111,445 Arran and Ailsa Craig 343 synclinal 445 Ireland 343-4 syn- 321 Lundy 344-5 Basistoppen sill 439 Mull 339-41 bathymetry, N Atlantic, anomalously shallow 7, 11 St. Kilda 345 bauxite 373 Skye 342 Bay of Biscay, graded ash layers 412 Small Isles, the 342-3 beidellite 70 roIe ofpalaeomagnetism 339 Belig deposits, Western Red Hills, Skye, pyroclastic British Tertiary Volcanic Province 76, 268,305,414- breccias 368-9 16, 417,430, 443,444 Bill Bailey Bank 225,229, 230, 233, 271 aegirine 411 biostratigraphy and age, Danish Upper Palaeocene- difficulties in accurate dating of stages of volcanism MiddIe Eocene 395-7,399-400 446 biotite 205, 207, 210, 211,256, 257,258 dyke swarm orientation, control of 384 458 Index

British Tertiary Volcanic Province (cont.) Cleveland Dyke 27, 29 regional stress field controlling magmatism 388 clinoptilolite 80 silicic pyroclastic rocks of 365-77 clinopyroxene 70, 78, 187, 192, 197, 263,278 stress and dyke emplacement 381 brown 274 brittle deformation 430 CnpanBreaca, Rhum 369, 370 brookite 411 coal-bearing formation/sequence, Faeroe Islands Bryozoan Sand 265 120, 217, 226, 234, 235, 266, 442 buchites 448 late Palaeocene pollen assemblage 267 Bulimina mMwayensis 263 coal seams, Suduroy 226 bytownite 124, 263,277 coals, devolatized 29 coastal flexure, E Greenland 201,211 Coire Uaigneich granophyre 342, 355 calcite 70, 78, 163, 165, 228 compaction, during crystallization 299 microcrystalline 316 compression 87, 421,422 calderacollapse 372,436 and extension axes, rotation of 386, 388 caldera formation 370 Faeroes 236 surface 375 Sverdrup Basin 222 caldera subsidence 431 Conachairgranite (St. Kilda) 345 calderas 151,376, 377 dating of 446 basaltic 372 cone-sheets 149, 357 silicic 372 Clermont Carn region 358 Camasunary Skerryvore Fault 386, 388,444, 445 emplacement 439 Canna lavas 342 formation 431 alkaline basalt 445 conglomerate 342, 434, 445 Cape Verdehot-spot 8 arkosic 434 Cape Verde Rise, mantle plume model 8, 9 basal 438 carbonates 80, 256, 257, 398 basaltic 226 carbonatite 441,447 volcanogenic 439 Carlingford central intrusive complex 344, 349, 361, contamination, of Faeroese basalts 226 374, 386, 387,444 continental break-up, Eocene 20, 22 age of 357-8 continental contamination 51 Carlingford granophyre 344 80, 225 cataclastic structures 375 attenuated 66, 101,123,293 Causeway Basalts (Middle Basalts), Antrim 343 layered 42 celadonite 70, 125 Rockall Plateau 130 Celtic Sea Basin 324 stretched 111 Central graben 388 thinned 309 central intrusive complexes 337, 361,365,415, 431, continental failure 430 432, 436, 440 continental flood-basalt provinces, Phanerozoic 436 Ardnamurchan 341-2 continental lithosphere, sourcing Lower Lavas, E development of 439 Greenland 188 migration of centres of activity 386, 387 continental margins Mull 339-41 Biscaytype 118-19 NE Ireland 344 N Atlantic 3 Rb-Sr isotopic determinations and timing 349- rifted 3 58 V~ring 49 Rhum 342 continental separation 440 Skye 342 'active volcanic' 111 and stress fields 386 convection, in mantle plume 8 central volcanic complexes 444 convective flow 19 chabazite 228 cordierite 65, 78, 256, 300 chalcedony 78 core-mantle boundary 21 chalk 315 corundum 301 Charlie Gibbs fracture zone 158,222, 325, 331 crater infill 372 chert 316 cristobalite 301,397, 403 chlorite 125, 163, 165,256, 257, 299, 300, 305,367 crush breccia 374 chloritization 203,259 crust chrome-endiopside !70, 192 high density, transtensional zone 136 chrome spinel fractionation 169 high velocity 5 chromite 300 Icelandic-type 21 chromite crystals 169 igneous, thickness emplaced during rifting 10 Clare lineament 331 intermediate-type 248 clay minerals 397 low velocity 38, 42-3, 45 claystone 255,263-65 formation of 43 Index 459

oceanic see oceanic crust Voting Plateau 79, 80 pre-Tertiary, E Greenland 189~0 Danea mutabilis zone 265 thickened beneath rifted margins 5 Darwin igneous centre 293, 294 transitional 54 Davis Strait, tension 431 crustalaccretion 152 debris flows 322 subaerial, Pfilmason model 95, 103-5, 111 Deccan Traps 191 crustal anatexis 440 d+collement 422 crustal assimilation 80, 171,376 deep mantle temperatures, raising of 43-4 crustal attenuation 57, 432 Deep Sea Drilling Project (DSDP) crustal blocks, rotated 439 Leg 48 123-32 crustal complexes Leg 81 57-66, 123-32 Iceland Site 550 400 decrease in number with age 152 Deflandrea oebisfeldensis acme interval 399 distribution dependent on crustal age and deformation 158 tectonic setting 153 brittle 430 representingpalaeo-rift zones 152-3 compressional 29 crustal construction process, Iceland, models for 152 intraplate 29 crustal contamination 128, 130, 188, 190, 191,301, and mobilization of deep salt layers 421 303, 305, 354, 356, 362, 431,440, 443 oceanic transform faults 330 by siliceous sediments 172 plastic 430 British Tertiary Igneous Province 191 surface 19 selective(STSr) 36I, 362 thrust-ramp 422 crustal extension 53, 330 transpressional 144 and dipping reflectors 118 transtensional 144 JanMayen Ridge 87 degassing, of magma 375-6 late Mesozoic, Norway/Greenland 144 delta fans 287 M~re and Voring Basins 52 demagnetization crustal fracturing, and water influx 43 alternating field 216 crustal fusion, aluminous sedimentary rocks 448 thermal 216 crustal generation, Icelandic type 51, 53-4 Denmark, Palaeogene volcanism 395-403 crustal rifting 147 age 399-400 and associated ocean floor development, contrasted evidence for 397-9 styles of volcanism 200 source of the ash layers 400-2 crustal separation i24 Denmark Strait, magnetic anomaly dating difficult crustal shortening 144,422 96, 99 crustal stress patterns, fundamental change in, density instabilities 45 Faeroe-Greenland Volcanic Province 417 depleted component, Lower Lavas, E Greenland crustalstretching 118-19, 130, 131,136, 144 187-8 crustal structure, deep, of Norwegian and Greenland depocentres margins 42-3 Faeroe Islands 228, 235 crustal tension, relief of, NE Atlantic rift zone 417 Tertiary, Western Barents Sea Basin 423 crustal thickness 40, 42, 105, 108 depositional environment, Tertiary sediments, increase in, Norwegian and Greenland margins 43 Wyville-Thomson Ridge and Hebrides Shelf crustal thinning 5, 45, 131,330, 439 278-9 and location of intrusive centres 365 detachment planes 90 crustal velocities, lower crust 65 deutericalteration 217, 219 crustal weakness, and preferential channelling of devitrification 259 magma 431 devolatization 29 crystal fractionation 71,431,440, 447 diachronism, Slyne Fissures 319 crystallization time 339 diagenesis 110 Cuillins, central intrusive complex 342, 343 diagenetic cement, cristobalite 397 cumulates diapiric doming 131 layered 431,439 diapiric emplacement, Brendan Igneous Centre 322 ultramafic 441 diapirism 332, 440 mantle 130 diapirs, granite 431 dacite 293, 300-1,448 diatoms 263 peraluminous 62, 65, 80, 442 differentiation 366 Rockall Trough acid magma, Mourne Mountains 354 cordierite-hypersthene 305 diffraction hyperbolae 57, 63, 66 cordierite-phyric 300 dilation 386 generation of 306 dilation axes 382-4 geochemistry of 302, 306-7 Dingle Dyke 344 Pb-isotope characteristics 303 Dingle Peninsula 460 Index

Dingle Peninsula (cont.) across intrusive bodies, and dyke swarms 385-6 dykes 444 diapiric 131 dolerite, dating of 446 of Jurassic strata 320-1 dinoflagellate zones, and Danish ash layers 396, 399- of late Kimmerian unconformity 320 400 Mull 372 dinoflagellates 265, 278 of reflectors 244 Danish Upper Palaeocene-Middle Eocene top Chalk 319 sediments 395-7 Doon Hill, Connacht 312, 320 diorite 21t,447 downfaulting 144 dip reversal 103 downwarping 386, 430 dipping reflector styles, NE 57-66 thickening of lava pile 431 geometry of the reflectors 58-64 Dracodinium simile zone 400 nature of the reflectors 65-6 Dracodinium varielongitudum zone 400 dipping reflector wedges 57, 90, 91,100-1,108, 112 drainage reversal 144 composition of, Varing Plateau marginal high 51 Droimchogaidh Sill, Connacht 344 dipping reflectors 3, 5, 7, 10, 36-7, 50, 54, 69, 104, dyke complexes 120--1,135,284, 287, 307, 417,442, 443 ophiolitic, sheeted 248 beneath marginal highs, Norwegian-Greenland Sea sheeted 431 49-50 dyke emplacement 381,385, 386 Bjarnoya marginal high 137, 141 major phase 386 controls on distribution and deposition 63 passive 385 determining age of 96 dyke intrusion 53 E Greenland 95-112 Britain 29 comparison with Iceland 103-5 dyke and sill emplacement 323-4 distribution and geometry 96-101 dyke swarm axes 386 initiation of seafloor spreading above sea-level distribution and orientation 381 111 dyke swarm orientation, controls on 384-5 origin 101-3 dyke swarms 10, 25, 131,132, 148, 162, 201,361,436 velocity structure 105-10 Arran 385 Faeroe Islands basaltic 435 coinciding with gravity high I 18 coast-parallel 211,439 geometry of 58-64 intensity of 439 divergent-arcuate (western Varing Plateau) 58- Kangerdlugssuaqcoast 205,439 9, 61, 62, 65 coastal 436-7 divergent-planar (Mare Basin) 58, 60 continental margin 161 flexured (western Rockall) 58, 62-4, 66 development of 430-I subparallel (southern E Greenland) 58, 62 with time 385 Iceland-GreenlandRidge 98, 99, 100, 101 Donegal-Kingscourt, Thulean 330 Jan Mayen Ridge 85, 87, 90, 92 interpretation of swarm and dilation axes 381-4 ageof 91 tamprophyre 432 and lava flows 3 linear 337, 381,443 models for Varing Plateau sequence 52-4 NW-SEtrend 339, 381 N Atlantic, zone width 4 lower crustal structure 384 Norwegian-Greenland Sea margins 37-43 Morvern 385 otttapping development 100 postflexure, E Greenland 205 origin of 116-19 Rhum 342 SW of Rockall Plateau 123-32 secondary 384, 388 subaerial oceanic origin 102 control of orientation 385 underlain by igneous crust 43 representing component of dextral shear 386 disconformities 430 sigmoidal 381,383 dissolution 39I Skye 383, 384 dolerite 163, 165,201,245,254, 312, 316, 361,369, NW-SE trend 342 376 Small Isles 383, 384 analcime-olivine 320 subswarms 386 oceanic 246 Tertiary, NW Britain 383--4 olivine 124, 245, 320 dyke systems tholeiitic 320 Connacht 311,319, 330, 331 pegmatitic 245 alignment similar to Slyne Fissures 324 Slieve Gullion 361 County Kerry 330,331 domes intrusive activity 324 rift 330 Dingle Dyke, N-S trend 344 structural, Faeroe Islands 229 Galway, Mayo and Connacht 320 Tardree 373 HaigFras Basin 325 doming 431 olivine-dolerite 311 Index 46I

Western County Kerry 320 enrichment, during alteration 80 dykes 27, 65, 158,201,227 epidote 163, 165,367 basalt 227,343 epigranite 361 basaltic 339 Erlend volcanic complex 229,244, 253,332, 443 Angmagssalikarea 119 Erlend Volcano basic, tholeiitic 161 explosive climax 261 cross-cutting relations with central complexes 385 source of N Sea ash marker tufts 260-1 dolerite 205 erosion 141,430 Donegal and Killala Bay, NW-SE trend 344 basin margin 272 early Tertiary 444 subaerial 368 high-Mg Erqugt Formation 432 Flado 167 erratics 229, 230 Kraemer O 167 eruption point, migration with time 366 lamprophyre 205,207,210, 211,440 eruptions multiple, flow-banded 320 along spreading axis 120-1 NW-SE to N-S orientation, tectonic and structural central vent 433 control 384,443-4 fissure 365,386, 433 porphyritic 165 hydrovolcanic 414, 417 postflexure 211 Plinian-type 78,415-16 regional NW-SE extension as dominant control rhythmic 372 383 Surtseyan-type 414 ring-dykes 339, 357,368, 374, 376, 387 eruptives, peratuminous 448 as stress indicators 381 escarpments 442-3 THOL-1 163-5, 170, 172-3, 176, 201,205 basalt, origin of 116 THOL-2 165, 168, 173-4 as faults 116 parallels with Icelandic basalts 174 lobate 119 tholeiitic 75, 78,80 NE Rockall Trough 283-4 TRANS-1 165, 168, 174 small, lava fronts 116 tuffisite 373,375 estuarine sequence, volcaniclastic rocks 69 dykes and sills, E Greenland, K-Ar analyses 206-7 Eurasia Basin 49 Eurasian plate 29 Expanded Spread Profiling (ESP) 38 earthquakes, deep-focus 15 explosion breccia 365,369 E Greenland explosive vents 255 coast marginal dyke swarms 439 extension 52, 120, 383, 384, 421,434 early basalts 132 by normal faulting 104 eruptive mechanisms 197-200 continental, basalt eruption 118 flexure zone 440 contribution of feeder dykes 66 distanced from evolving spreading centre 440 lithospheric/crustal thickness relation 51-2 Lower Tertiary lavas, palaeomagnetic study 215- NW-SE, synchronous with similar phase in North 22 Sea 388 palaeomagnetic poles 220, 221 passive mechanism of 45 peralkaline 416 extension, volcanism and subsidence, relation between southern, subparallel reflectors 62 119-21 E Greenland continental margin,timing of magmatic extension systems, en echelon 119 activity 201-12 extension zone, southern North Sea 29 E Greenland Tertiary Igneous Province 201 extrusion 145 isotope geochemistry of the Lower Lavas 181-93 basaltic 63 E Greenland Tertiary lavas compared with Skye lavas of seaward-dipping reflectors 5 191 subaerial 53, 299 E Greenland Tertiary Volcanic Province 197 submarine 66 Eastern Red Hills, Skye 342 and tectonic setting of a volcanic rifted margin dating of 446 144-5 416 extrusives 51 pyroclastic breccias 367 basaltic 433 Eatonicysta ursulae 400 early Eocene 53 Edoras Bank 124 early Tertiary oceanic crust 112 EdorasBasin t23, 124 rhyolitic 446 EidiMember 227, 228,230 low-Ti olivine tholeiites 235-6 Eidis Series 227 Faeroe Bank 225,229, 230, 233, 271 Eigg 342, 345,446 Faeroe basalt plateau alkaline basalt lavas 445 continued in Rockall Trough 230 Ekofisk Formation 407 extending into Faeroe-Shetland Channel 229 462 Index

Faeroe basalt plateau (cont.) antithetic 439 structure, composition and age 225-36 in the central complexes 386 accumulation rates 234--5 dextral strike-slip 388 age 234 extensional 331 chemical composition 230-3 Jan Mayen Ridge 87 evolution 235-6 late, NW Britain 386-8 structure 227-30 listric 248 submerged area, structure 229-30 normal 388, 430, 439 Faeroe basin and Rhine Graben 27 Faeroe Block 225,233,437 syndepositional antithetic 58 subsidence of 229 transform, RockallTrough 330-1 Faeroe-Greenland Igneous Province 265, 266 faults 236, 431 Faeroe-Greenland Volcanic Province 416 inherited from the Caledonian structures 445 explosive eruptions 417 normal 319, 386 Faeroe-Iceland-Greenland mantle plume 413,414 cutting lavas and central complexes 386-7 Faeroe Islands pseudotransform 158 basalts 217 reactivation of 25 chemical composition 230 reverse 87, 422 continental fragment 441 rift-marginal, rejuvenation of 434 igneous activity 441-2 sinistral transform 158 mean palaeomagnetic pole 220, 221 strike-slip 321,387 pre-driftreconstruction(s) 438,441 thrust 422 stratigraphy 226-7 transcurrent, imposing structural and igneous structure 227-9 modification 331 Tertiaryvolcanics 128 fayalite syenite 211 Faeroe Rise 225 Fe-saponite 70, 78 chemical composition dredged basalts 230, 233 Fe-Ti-oxides 70 Faeroe Risemicrocontinent 225 feeder dykes, and dipping reflectors 66 Faeroe-Shetland Basin 241 feeder vents 5, 7 extension of North Sea graded ash layers 412 feldspar 197, 203, 316, 398, 411 Faeroe-ShetlandChannel 121,225 interstitial 275 northern, subsidence of 119 K-feldspar 299 Faeroe-Shetland Escarpment 49, 115, 119, 437,443 microlitic 409 formation of 121 felsite 361,371,372, 375,376 igneous activity 442-3 flow structure 369, 374 Faeroe-Shetland Escarpment transect 42 porphyritic 344, 374 Faeroe-Shetland margin 52 Rhum 369, 370 Faeroe-Shetland sill complex Fennoscandia, postglacial recovery 20 age of sills 241-5 ferroaugite 125 chemistry of 245-7 ferrobasalts 230 emplacement of 248 ferrohypersthenes, acicular 78 geochemistry and origin of 241-51 fiamm~ 369-70, 375, 376 K-Ar ages 241,244 partiatly-devitrified 372 location 242 fining-upward sequences 77, 78 MORB-type rocks 246-7 Fionn Choire, Skye 366, 369, 373, 376 relationship with Faeroes lavas 249, 251 Firkanten Formation 141 structure 241 fissure eruptions 102, 120, 229, 322, 386, 433 transgressive form of 243, 244, 249 basaltic 365 Faeroes area, proposed time-scale of early Tertiary fissure swarms 151 volcanic events 267 fissure venting system, axial 321 Faeroese Shelf, parallel-bedded reflectors 116 fissure volcanism 439, 446 Fairy Bridge basalt 299 fissure volcanoes 320, 430, 434, 437 fanglomerates 322, 323 fissures 152,376 Fastnet Basin 312, 325 Flad~ Bathonianintrusives 320, 325 dyke swarms 162, 165 Jurassic faulting and intrusions 331 dykes 167 fault block rotation 158 fexureline, Svartenhuk 434 fault blocks flexuring 158, 291,436, 439 Jan Mayen Ridge 87, 91 coastal 161,441 tilting of 445 S and SW of the Faeroe Block 229 fault reactivation 385,386, 388,446 flood basalts 217,436, 437 fault-scarps 433 Blosseville Kyst 193 fault trends, Jan Mayen Ridge 87 continental, lithospheric mantle sources 192 faulting 434, 436 tholeiitic 181 Index 463

folds, asymmetric 422 Globigerina gr triloculinoides 265 foraminifera 278 Globorotalia chapmani 265 Forlandsundet Graben 421 glomerocrysts 124 Forties sand 408 gneiss, Archaean 189-90 foyaite 211,447 Goban Spur 320, 322, 325 fractional crystallization 170, 306 graded ash layers 412 fractionates, extreme 373-4 Goban Spur Basin 312, 314, 322, 325 fractionation 197, I98, 357 igneous activity 330 crystal-liquid 376 gonnardite 299 high-pressure 376 graben 309 low-pressure 127-8,433 graben/half-graben development 430 olivine 169, 199 Davis Strait 431 in open magma chambers 166--7 graben/half-graben zone 445 and Sr addition 361 graben system, Baffin Island-W Greenland 432 fractionation residues, late 448 grain size, Danish ash layers 400-2 fracture system, NW -Alps 29 granite 211,411,416, 432, 447 Fur Formation 395, 397 aegirine 442 age of 400 crustally contaminated basaltic differentiate 354 graded ash layers 412 grading from peraluminous to peralkaline 447 silicoflagellate biostratigraphy 400 Lundy 344-5 Fur (island) Mourne Mountains 344, 346, 350, 358, 387-8,446 ash layers 399 Rb Srdata 350-5 thickest and coarsest ash layers 402 Skye 342 granodiorite 355, 376 granophyre 342, 344, 350, 361,369, 432 gabbro 320, 344, 361,368, 369, 374, 391,432, 436, aphyric pyroxene 357 439, 447 porphyritic 357, 376 Carlingford 361 granulite facies 191 feldspar-phyric 376 granulites Killala (Ros Gabbro) 320, 322, 344 contamination with 190 layered 344 Rockall Plateau 129, 130 Gallic subplate 29 gravity anomalies 447 Gardiner Complex 441 and deep isostatic compensation 19 aegirine 416 positive 135, 136 ring-complex 440-1 gravity highs 49, 118,316, 319 Gardiner intrusion 205,211 Brendan Igneous Centre 319 gas-streaming 368-9, 371 N Atlantic, correlation with topographic swell 19 G~tsefjord 215 Great Glen Fault 444, 445 gastropods 278 Greenland-Barents Sea boundary 421 Gauss-Halvfl, change in basalt character 435 Greenland continent margins 431 Geikie Plateau Formation 438 Greenland escarpment transect 40, 42 geoid and gravity anomalies Greenland fracture zone 222 cause and possible sources 18-19 Greenland-Iceland-FaeroesRidge circum-Pacific subduction zones 16 crustalthickness 7, 11 N Atlantic 17-20 see also Iceland-Faeroes Ridge combined effect of thermal and pressure Greenland-Iceland Ridge 21 anomalies 2t-2 Greenland plate, renewed internal stress 417-18 geoid highs, over hot-spots 19 Greenland Sea geomagnetic polarity reversal 147, 153 openingof 135, 136, 211 rate of 148 Greenland-Senja fracture zone 157 see also reverse polarity greenschist facies 110, 112, 163 George Bligh Bank 225 groundwater interaction, E Greenland intrusions 205 geothermal activity 151 groundwater/magma interaction 414 geothermal gradients 110, 112, 118 Giant's Causeway 343,446 Giesecke Bjerge, hyaloclastites 434 Haengefjeldet, THOL-I dyke swarms 162, 163-5, glass 167, 170 devitrified 278 HaigFrasgranite 325 alteration stages 275-6 Hampshire Basin, evolution of 29 interstitial 296 Hatton Bank 49, 50, 124, 225 peraluminous rhyolite 448 Hatton Bank continental margin 4, 5, 6-7 tholeiitic 263 Hatton-Rockalt Basin 225 volcanic 397, 408 hawaiite 203 glauconitic marker 124 Hebridean igneous activity, dating of 446 464 Index

Hebrideanlavasuccession 445 Igdlitarajik 210 Hebridean region igneous activity as source of North Sea volcaniclastics 409, 411 Cretaceous 429-30 Hebridean volcanic sequences 415 extrusive 315 Hebrides Shelf 271 Faeroe-Shetland sill complex 243 sediments 272-3 Jurassic-Tertiary 327-9 Helen's Reef, microgabbro 345 Lower Tertiary, Britain and Faeroe Islands 222 heulandite 70, 77, 301 119 Highland Boundary fault 444 Mesozoic and Tertiary, Porcupine Seabight Basin Hold With Hope peninsula 434 analysis of 320-4 change in basalt character 435 evidence for 312-20 Holmehus Formation 397, 399, 403 Porcupine Seabight Basin mineral composition of clay 398 Lower Cretaceous 325 Hordaland Group 254 regional affinities 325-30 hornblende 165,205 tectonic and igneous implications 330-2 hornfels 254, 255,256, 257,260 Tertiary 325 Hornsund fault zone 135, 136, 137, 144, 421 post-rift 330 oblique relationship to Senja fracture zone 422 Tertiary, N Atlantic borderlands 429-48 Hornsund fracture zone 423 Baffin Island-Greenland 431-4 hot-spot migration 151 Britain and Ireland 443-7 hot-spot model 8-11 central E Greenland 436-41 hot-spot and plume hypotheses, implications of 20-1 Faeroe Islands 441-2 hot-spots 3, 25 northern E Greenland, Scoresby Sund to Shannon Azores 19 Island 434-6 and continental break-up 20 Rockall Plateau and Rockall Trough 442 Iceland 19 Skagerrak 447 Iceland-Greenland Ridge 158 Voring Plateau and Faeroe-Shetland escarpment Icelandic, causes and consequences of 15-22 442-3 influencing spreading 44 Tertiary, timing of 7 Kangerdlugssuaq 158 timing of 10~ll Hutchinson Glacier syenite I 210 igneouscentres 293,306, 319-20 hyaloclastites 124, 161,287, 321,325,432, 434 margins of Porcupine Seabight Basin 309, 3ll hyalopilitictexture 124 igneous crust hybridization 391 thick, and dipping reflectors 45 hydrocarbons 307 thickened under margin 11 hydrothermalactivity 341,376 igneous occurrences, regional, continental shelf, W of hydrothermal alteration 80, 186, 339, 365,440 326 hydrous alteration 256, 258 igneous reactivation 331-2 hydrovolcaniceruptions 414, 417 ignimbrite 80 hypersthene 78,256 Igtertiva Formation 181,183, 187, 189, 193, 439 illite 398 ilmenite 78, 197, 257, 300, 411 Iceland Imilik gabbro 440 distribution of volcanic complexes 151-2 inclusions east 77 bytownite 300 eastward displacement of rift zone 158 Mg-chromite 70 magnetic observations 147-9 incompatible element abundances, Lower Lavas, E NW submarine extension 152 Greenland 168-9, 170-4, 182, 188,189 subaerialseafloor spreading 103-5 Voting Plateau 77 Iceland mantle plume 8, 11 incompatible element enrichment 71,174 asthenospheric outflow 21 incompatible elements Iceland-Faeroes Ridge 8 acquired from grain-boundary assemblages 175-6 anomalously thick crust 21 decoupled variation in 190--1 Iceland-Greenland Ridge 103, I05 inner-shelf environment 312 dipping reflectors 98, 99, 100, 101 Interbasaltic Formation, Antrim 343,355, 373 formation of 158 intraplate deformation, Gallic subplate 29-30 subaerial seafloor spreading 11 t intraplate swells 8 Iceland Plateau 85, 90 intrusions 439-40 Icelandic hot-spot 44 alkaline 201 causes and consequences 15-22 arcuate 341-2 Icelandic Shelf 95, 98 basic 201 Icelandic transverse ridge 15, 22 E Greenland, dating of 205-11 anomalously thick crust 16, 21, 22 hypabyssal 203-11 iddingsite 275-6, 295 igneous 43 Index 465

Killala, gabbroic, Ros Gabbro 312, 320, 322 Kap Gustav Holm lower crustal 388 extension zone 119 mafic 151 gabbro 440 minor 337 Kap Parry multiple 372,436 alkaline complex 210-1! rhyolitic 151 central intrusive complex 436 syenitic 440 Kap Simpson central intrusive complex 436 Tertiary granite and syenite 211 Kap Syenit central intrusive complex 436 intrusive bodies, lower crustal 385 Kialineq complex 210, 211,440 intrusive centres see volcanic centres Kilchrist, Eastern Red Hills, Skye 367, 368, 375 inversion 5, 25 Killala Gabbro 320, 322, 344 NE Porcupine Basin 322 kimberlites 192 radial 332 Kisselovia coleothrypa zone 400 StappenHigh 141,144, 145 Kivioq Fjord, E Greenland 205 inversion tectonics 29 Klaksvik flow, silicic 229 Ireland 343-4 Knudshoved Member 400 igneous activity 443-6 Kolbeinsey Ridge 21, 75-6, 85, 158 silicic pyroclastic rocks Kollafj~rdur Member 227,228, 229, 230 extrusive rocks 373-4 Kong Oscars Fjord 210, 211 Slieve Gullion 374-6 Kraemer ~O Western, igneous outcrops 320 dyke swarms I62 Irminger Formation 162 THOL-2 dyke swarms 165 isostatic compensation, deep 19, 21 Kraemer t0 syenite intrusion 205, 21t isostaticequilibrium 5, 10 Kruuse Fjord layered gabbro 440 isostatic uplift 21 Alpine Range 27 isovelocity contours 38, 39, 40, 41, 42 La/Ta ratio 279 indicator of source character 127 Labrador Sea, commencementof active seafloor Jan Mayen Fracture Zone 77, 90, 119, 158,222, 443 spreading 431 Jan Mayen Ridge 50 labradorite 124, 125, 257, 263,278, 301,411 subparallel reflectors 63 laccoliths, inferred 321 Tertiary sediments 91 laminar flow 374 Jan Mayen Ridge microcontinent 21,158 lamproites 192 tectonic and volcanic events 85-92 lamprophyre 434, 447 plate tectonics 85 high-pressure fractionation residue (Ubekendt) structure 85, 87, 88 447 timing and evolution of 91 lapilli 227 volcanic provinces 87, 90-1 accretionary 78 pumiceous 77 K-Ar dating laterite 343 Ardnamurchan rocks 342 lava 366 basic igneous rocks 258,259-60 alkaline 203,204 Rockall Trough voIcanics 304-5 Antrim 343-4 kaersutite 210, 411 basalt 342, 343,344 Kaiserstuhl volcanicity 27 subaerial 434 Kangerdlugssuaq dome, uplift of 21 basaltic 120,415,417, 430, 440 Kangerdlugssuaq hot-spot 158 basanitic 440 Kangerdlugssuaqlineament 436, 441 basic 349 Kangerdlugssuaq region 181 silica-undersaturated 436 change in tectonic environment and type of Blosseville, Fe-Ti-rich oversaturated tholeiite 438 magmatism 441 compound 372 coast-parallel dykes 439 early Tertiary, NE Rockall Trough 283-91 Tertiary volcanism 16t-77 E Greenland geochemistry 166-73 K-Ar analyses 204 regional outline 161-2 lower Tertiary, palaeomagnetic properties 215 sampling areas and petrography 162-5 17 Kangerdlugssuaq syenite intrusion 201,207, 211,440 reverse polarity 218-19 kaolinite 367, 398 areal distribution of facies 287-9 Kap Boswell syenite intrusion 201 implications for subsidence 289, 291 Kap Dalton, volcanogenic conglomerates and seismic character and interpretation 283-7 sandstones 439 sub-lava intrusions 289 Kap Deichmann syenite intrusion 201,210, 211 Eigg 343 Kap Edvard Holm 439 Faeroese sequence 226, 244 466 Index

lava (cont.) lava sheets 283 dating of 234 lead isotope geochemistry, basalts SW of RockaII hawaiitic 440, 445,446 Plateau 128-30 Kangerdlugssuaq region, Lower basalts 162-3 teucogranite 361 late Palaeocene, Erlend Complex 244 LIL element depletion 127, 128, 130 Mikis-type 167, 170 Lillebaelt Clay Formation 397,400 Mull 339-40 Lilloise intrusion 205, 207, 211 nephelinitic 440 limestone 315 parental, Fe-Ti tholeiite 412 Danian 316 pitchstone 342 ListaFormation 254, 399 porphyritic 442 basal tufts 260 Prinsen af Wales Bjerge (PWB) 199 listric fault complex 87, 90 quartz tholeiite 435 formation of 91 rhyolite 372, 373 lithosphere Scoresby Sund region, cyclical compositional continental, fracturing of 46 variation 438 enriched, influence of 175-6 Skye 342 fundamental zone of fracturing 439 subaerial 291,430 Pacific, subducting 15 Tertiary 443 subcontinental Britain, reversed polarity 217 E Greenland 192 tholeiite strongly depleted 132 olivine 442 U-depleted 128-9, 130 silica-oversaturated 442 two-layered 53 tholeiitic 197,438,441 lithosphere-asthenosphere boundary 53 trachytic 369 lithospheric elevation 19 lava edges (scarps) 291 lithosphericextension 45, 53 build up of 284, 286, 287 melting due to pressure release 44 lava fields 430, 434 lithospheric mantle component, Lower Lavas, E basalt, erosional remnants of 434 Greenland 182 Hebridean 446 lithospheric plate drag 19 see also lava plateaux lithospheric stretching 5, 8-9, 130, 330 lava flows 85, 87 accompanied by vertical movement 439 andesitic, subaerialextrusion 53 causing pressure perturbation 1t basalt 65, 101,112, 115, 376 lithospheric thinning 10, 45, 53, 176, 430 andesitic 78, 79 differential 53 thoIeiitic 434 Liverpool Land margin 91, 92 basaltic-andesitic 51 LochAinort epigranite 342,416 cut by normal faults 386 LochBaCentre 387 dacitic 78 LochBaFetsite 339, 372 fine-grained 69 Loch Don Anticline 387 glomerophyric 124 Lofoten-Vesterolen islands 52 Goban Spur Basin 312, 325 Long Loch Fault 387,445 icelandite 446 Loppa High 141 Lower Basalt Formation, Faeroe Islands 228 Lopra drill-hole 226, 228,234, 235 magnetization of 216, 217 Lousy Bank 225,229, 230, 233, 271 obsidian 373 Lower Basalt Formation, Antrim 276, 306, 343,373 peraluminous-andesitic 51 Lower Basalt Formation, Faeroe Islands 119, 120, porphyritic 226 226, 227-8,230, 235 rhyolite 365, 373,376 accumulation rates 234-5 stacked 3 subsided during extrusion 228 subaerial 65, 131,432 Lower Basalts, Kangerdlugssuaq region 161,268 basaltic 91 depleted tholeiites, Iceland type 167-8 submarine 90, 132, 322 depleted tholeiites, Icelandic type 167-8 T-MORB composition 70-1 geochemistry of 166-70 tholeiite, Mg-poor 433 incompatible element geochemistry 170-3 tholeiitic 446 major element composition 168-70 trachyte 365 Mikis-type lavas 167, 170 Upper Cretaceous 315 picrite-ankaramite series 166, 167, 168-70, 170-2, vesicular 124 176 lava migration 120 tholeiite series 166-7, 170, 172, 173 lava pile, structure of 148 lower crustal intrusions 388 lava pillows 248 Lower Lava Series, Faeroe Islands, tholeiitic 416 lava plateaux 430, 446 Lower Lavas, E Greenland early Tertiary, Faeroe Islands 441 enriched component 188-93 Index 467

lithospheric component 192-3 rhyolite 356-7 inferences from geochemistry of lava groups 188-9 salic 440, 447 isotope geochemistry of 181-93 felspathoidal 447-8 picrite-ankaramite serieslavas 189 silicie 374, 375, 376, 415 reservoir types 192 volatile rich 368-9 Lowerlavas, Kangerdlugssuaq 438 Slieve Gullion, generation of 358 Lower Plateau Basalts, E Greenland 201 tholeiitic 80, 118, 125,376 Lower Series, V~ring Plateau 59, 65,443 ultramafic, intrusion of 391 lithology and petrography 78 80 ultrapotassie 192 sediments 80 V~ring Plateau 71 Lower Series basalt lavas, E Greenland 435 magma ascent 433-4 Lower Series basalts, Antrim 446 British Tertiary Volcanic Province 443 Lower Series basalts, Faeroe Islands 217-18,222, magma chambers 151,197-200, 211,306, 366, 376, 266, 268,279, 280, 281,441-2 431,436, 439 normal polarity intervals 267 magma generation 438 Ti-rich tholeiites 266 magma mixing 192, 193, 197-9, 361,431,447 Lower Tertiary Igneous Province, N Atlantic 217-19 inhibited 306 LREE, Icelandic basalts 246 magmaponding 306,439 LREE depletion 125, 127, 130, 186, 445 magma pressure 248 LREEenrichment 197, 297 magma sources Lundy granite, dating of 446 picrite-ankaramite series 174 Lundy Island 344-5, 346, 444 recent 80 magma replenishment 197-9, 200 magma ridges 25, 384 Maclean's Nose, Ardnamurchan 371,373 feeding dyke swarms 386 maculose fabric 256 magma-gas emulsion 375 MaggaDan Formation 438 magmaticerosion 176 magma 20 magmatic thinning and extraction model 176-7 acid 354, 362 magmatism alkaline 211,440, 447 alkaline 211,372, 376 marie, Si-deficient 447 basaltic 253-61 volatile-rich 376 basic, tholeiitic 211 alkaline affinities 376 Cretaceous 322 anatectic crustal 43t late-stage 440 basaltic 131,257, 260, 306, 413, 415, 445 magnitude of the controlling stress field 385-6 change to MORB type 431 N Atlantic, observations on 3-8 crustal 80 opportunistic 330 daeitic 306, 370 tholeiitic 446 eruptionof 111 tholeiitie basalt 440 evolution of type with time 176 Thutean 325 ferrobasaltic 77 Thulean related 332 granitic 447 magnetic anomalies 7, 51,153, 158, 319, 330, 447 high-K 79 Brendan Igneous Centre 319, 322 intrusion of, sill-sediment complexes 248 Iceland 147-9 lamproitic 192 localized 148-9 lateral injection of 331 offset 149 marie 376, 440 magnetic quiet zones 95, 96 mixed 371,372 magnetic vectors, stable 216 mixed-crustal source 303 magnetite 197, 257,316 oceanic basin 256 mantle convection 17, 18 palaeohydrostatic head of 320, 321 in an extensional environment 45 parental and plume hypothesis 15-16 alkaline 376 mantle diapirism 130 basic, mantle-derived 361 mantle jet 181,193 peralkine 411 mantle melt extracts 447 picrite 175-6 mantle melting 434, 436 picritie tholeiite 433 mantle plume hypothesis 15-16 Skaergaardintrusion 167 consequences of 22 peralkaline 447 criticisms 15 picrite-ankaramite series 174, 176 mantle plumes 8, 10, 21,413,417 plume-derived, diversion to ocean-ridge crest 20-1 conduit for upward flow of hot material 16 porphyritic felsite 371 Faeroes-Iceland-Greenland 413, 414 preferential channelling of 431 Iceland 8, 11, 21 primitive t99, 436 producing high pressure in asthenosphere 20 468 Index

mantle residuals 192 N-type 75, 127, 130, t 31 2, 246, 442 marble 316 T-type 75,246, 247 Margareta's Spur 253 mordenite 78-80, 301 margin subsidence 124 More Basin 49, 52, 119, 241,253 marginal chill, glassy 256 divergent-planarreflectors 58, 60 marginal highs formation of oceanic and transitional crust 243 Bjornoya 135, 137, 141,143, 144 sill intrusion 248 formation of 49-54 More extension zone 119 markers Mors 399 ash 141,229, 234, 260, 325,442 Morvern dyke swarm 385, 387 glauconitic 124 Mourne Mountains central intrusive complex 344, seismic 137, 141 349, 361,444 volcanic 3, 85, 90-1, 92 main intrusive activity 358 mass-flow deposits 91 Mourne Mountains granites 344, 346, 350, 358 Maureen Formation 408 dating of 446 MealtBreac, Rhum 369-70 faulting of 387-8 melilitolite 447 Rb Srdata 350-5 melt Muck 342 basaltic 120 alkaline basalt lavas 445 picrite 176 mudstones, siliceous 412 residual basaltic 391 mugearite 342 mesolite 299 Mull 339-41,345,346, 445 metamorphic alteration 186 Central Group 339 metamorphic aureole 254, 255,322 dating of volcanism 446 metamorphism t10, 129, 316 early plateau lavas 260 contact 255 flood basalts 217 thermal 241,256, 370, 375 Plateau Group 276, 305-6, 339 Mg-chromite 70, 295 silicicpyroclastic rocks 372-3 Mg-kataphorite 409, 411 Mull central intrusive complex/igneous centre 339, Mg-pigeonite 124 365, 386, 443 mica 80, 205, 257 faulting of 386-7 K-Fe 256 pyroclastic rocks 372-3 white 78 Mull Volcano, explosive climax 261 microfossils, siliceous 263, 265 Munkagrunnur 230 microgabbro 345 Myggbuktacalderacomplex 435-6 microgranite 350, 368, 369,376 Myggbukta Volcano 436 riebeckite 343 microphenocrysts 299 augite 165 labradorite 128 nannofossils, calcareous 397,407-8 olivine 299 natrolite 296, 299, 301 plagioclase 124, 125 Naviculopsis constricta zone 400 Middle Basalt Formation, Faeroe Islands 119,226-7, nepheline 207, 299 228, 229, 230 nepheline-hawaiites 436 accumulation rates 235 nepheline syenite 436, 440 Middle Series basalts, Faeroe Islands 218, 222, 266, nephelinite 436, 447 267, 268,281,441,442 net-vein complexes 211 Ti-rich tholeiites 266 Newry Fault 387-8 Mikis Formation 163, 192 NewryGranite, Caledonian 374 isotope geochemistry 187 Newry igneous complex, possible source for Mourne picritic flows 183 acid magmas 355,358 Milne Land Formation 438 nontronite 70, 397 Minch Fault 386, 388,445 nordmarkite 207 moat rhyolites 373 N Atlantic mobilization 141 evolution of 3-11 Mohns Ridge 157, 158 initial opening 181 Moho 108 pre-drift reconstruction 430, 441 depthto 5, 40,42, 105, 110, 361 Tertiary volcanism 416-17 Moho positions 105 topographic swell 16-17 Moho reflection 40 N Atlantic borderlands, history of Tertiary igneous montmorillonite 367 activity 429~48 montmorillonite/beidellite 78 N Atlantic geoid and gravity high t7-20 MORB N Atlantic margins, remaining above sea-level 5 NAMORB 129 NE Atlantic Index 469

before onset of seafloor spreading 236 ocean-continent transition 49, 50, 65-6, 103, 108, correlation of volcanic and sedimentary events 280 118, 135, 136, 137, 158, 181,235,289 early Tertiary basalts and tuffaceous sandstones, and dipping reflectors 57 Hebrides Shelf and Wyville-Thomson Ridge irregular 325 271-80 Ocean Drilling Programme (ODP) Leg 104 57-66, early Tertiary opening events 1 t9-21. 307, 443 multiple and propagating rift model 157-8 oceanic crust 11, 57, 95, 104, 129, 225,250, 293, 325 opening of 234, 235,358 accretion model 95 final, accompanied by tholeiitic plateau basalt early Tertiary, SE Greenland margin 112 magmatism 80 expanded 51 initial, dyke evidence 173 formation of three-stage opening 421 off-shore, E Greenland 2tl NE Atlantic margin, Tertiary structures 421,422 in pull-apart basins 248 NE Ireland incipient accretion of 325 Rb-Sr isotopic determinations and timing, Tertiary initial 144 central complex magmatism 349-58 mid-ocean ridges 118 ages of Carlingford and Slieve Gullion central new 132 complexes 357-8 Norwegian-Greenland Sea, shallow and ages of major Tertiary intrusive events 358 anomalously thick 35 Lower Tertiary rhyolites 355-7 thinning of 43, 44 Rb-Sr data, Mourne Mountains granites 350-5 two-fold thickening 38, 40, 42 strontium isotope geochemistry of Tertiary igneous young 99 rocks 361-2 oceanic lithosphere, new, subsidence of 431 Tertiary acid rocks 361-2 offlap 57, 58, 59 North Sea Basin offlapping reflectors 58, 60 change in patterns of tectonism and sedimentation olivine 124, 163,316 416 altered 299 Palaeogene clay mineralogy 402 reaction coronas 257 record of early Tertiary N Atlantic volcanism 407- serpentinized/chloritized 257 18 olivine crystallization 197, 198 North Sea stratigraphy 407-8 olivine fractionation 169, 199 volcaniclastic sediments 408-14 ~lst Formation 77-8, 397-8,403 North Sea gas fields 29 age of 400 North Sea stratigraphy 407-8 ash layers 399 N-S trend, Britain.and Ireland and KangerdIugssuaq onlap 57, 58, 59 'rift' 444-5 see also baselap NW Britain, early Tertiary stress regimes 381-8 opaques 299, 300, 301 late faulting 386--8 orthopyroxene 256 NW Europe, compression of 30 altered 245 NW Europe, Palaeocene-Oligocenetectonics 25-30 oxidation, low-temperature 216-17 British Tertiary Igneous Province, relationship to oxygen isotope ratios 341 Atlantic opening 27 North Sea connection 29 Rhine Graben, relation to Alpine Orogeny 27, 29 Pacific subduction zone 16 N Ireland, faulting 387-8 retreating 19 Norway Basin 91 palaeomagnetic pole positions Norwegian-GreenlandSea British and European Tertiary Igneous Provinces formation of 49 220 opening of 439 N Atlantic reconstruction 221 early, plate tectonic setting 137 palaeomagneticpoles 215,219-22 early Tertiary 144 palaeomagnetism 147 seismic structure 37~43 role of 339 Faroe-Shetland escarpment transect 42 Palaeoperidiniumpyrophorum informal zone 265 Norwegian margin 48-54 palaeoshorelines 284, 287, 291 Norwegian Sea, opening of 27 palaeosols 235 Nugssuaq peninsula 433 lateritic 445 Numrnulites rockallensis 278,279 palaeosurface, Voring Plateau 65, 66 palagonite 316 palagonitization 255,259 obsidian partialmetting 8-10, 71, 72, 75, 80, 127, 128-9, 131, perlitic 373 132, 198,279, 306, 358,376, 433,446 porphyritic 344, 355 6 convective 43 5, 46, 53 ocean-continent boundary 5, 52, 54, 59, 87,442 depleted mantle source 130 Faeroe-ShetIand region 66 of low Rb-Sr ratio greywackes 355 470 Index partial melting (cont.) plate adjustment, and magmatic activity, E Greenland in the mantle 431 211 reservoir rock 362 plate boundaries and rhyolite magmas, NE Ireland 356-7 accreting 144, 151 small-scale 445 divergent 45-6, 147-53 passive margin development 111 early Palaeocene 144 andpulse ofmagmatic activity 37 Hatton Bank-Eurasia Basin 49 passive margins 43,431 Iceland Norwegian volcanic, early Cainozoic evolution of accreting 151 49-54 divergent 147-53 rifted 50-1 plate collision, and stress fields 388 Rockalltype 123-32 plate decoupling 236 shelf 289 plate evolution, influence of N Atlantic thermal subaerialvolcanism 111 anomaly 21 subsidence and onset of seafloor spreading 52-3 plate motion 136 volcanic, and dipping reflectors 57 plate movement, Barents Sea area, directional change Pb isotopes 144 early Tertiary volcanics, Rockall Trough 302-3 plate separation 434, 436, 441 indicator of crustal contamination 191 coincidental with Caledonian orogeny trends, E Pb isotopic composition, Lower Lavas, E Greenland Greenland coast 434 187-8 plate tectonics, Jan Mayen Ridge 85 pegmatites 210 plateau basalts 75,287, 289, 361 peraluminous rocks 307 Antrim 349 peridotite 391,447 Skye 386 mantle, enriched 175 subaeriallyerupted 115 perlite 78 tholeiitic 447 petroleum source rocks 307 Plateau Basalts, E Greenland 183, 193, 235 petrophysical log cycles 314-15 isotope geochemistry 187 70, 78 palaeomagnetic properties of 215-17 augite 167 Plateau Basalts, Kangerdlugssuaq region 161,167 chrome-endiopside 163 fed by Flado and Haengefjeldet dykes 173 chromite 163 plateaulavas 415,416 cordierite 300, 305,306,443 tholeiitic 440 fayalite 375 plugs hedenbergite 375 dacitic 373 hypersthene 443 dolerite 344 labradorite 274 igneous, intrabasinal 319 magnesian hypersthene 300-1 peridotite 391 olivine 165, 167, 169, 197, 295, 299, 306 quartz porphyry 374 plagioclase 72, 124, 197, 277, 299, 375,443 volcanic 312, 320, 323-4, 323,325 flow alignment 274 plutonic and hypabyssal activity, E Greenland 211 unaltered glass inclusions 413 plutons pyroxene 197 basic, Cuillins 361 quartz 255,375 E Greenland 211 sanidine 375 mafic/ultramafic 443 Vestmanna drill-hole 227 pyroxene granophyre 374 phlogopite 205 pneumatolitic activity 376 phosphorus 170 polar wander, apparent (APW) 219 picrite 161,166, 186, 203,230, 432, 435, 438, 447 polarity time-scales 339, 340, 341, 345, 346 high-Ti 176 inadequacy of 148 pigeonite 78, 197 polarity zones 147 pillow breccia 432 thickness of 148 pillow lavas 321,325,430, 434 Porcupine Abyssal Plain 325 pilotaxitic texture 124 Porcupine Basin, upper 319 pitchstone 343, 345 Porcupine Igneous Province 330 plagioclase 70, 78, 124, 163, 165, 197, 203,255,256, Porcupine Median Volcanic Ridge 311,316-17, 318, 259, 263,274, 278, 295, 299 330 albitic 163 associated sills 319 calcic 316, 412 initiation of 320, 325 sodic 372 structure of 321-2 plagioclase crystallization 170 Porcupine Seabight Basin planktonic forminifera 265 igneous activity plastic deformation 430 Jurassic 312, 316, 320 plate acceleration 236 Lower Cretaceous 312, 314 15, 316-19, 320-2 Index 47I

Upper Cretaceous 315,320-2 remanencecontrasts 147 Tertiary 315-16, 319-20, 322-4 remanence polarity structure 148 syn- and post-rift igneous activity 309-32 remanences, stable 216 post-Devonian main fault, northern E Greenland remanent magnetization 153 434 residua, salic 43t potassium mobility 258 reverse magnetization, Upper and Middle Faeroe preferential chanelling of magma 431 Islands basalts 218 prehnite 163 reverse polarity 215, 339, 415,416 Preshal Mhor basalt/lavas 278, 299, 306, 446 and British Tertiary Igneous Province lavas 345, pressure perturbation 11 346 pressure variation, lateral, upper mantle 19 E Greenlandlavas 218-19 PrinsenafWalesBjerge 197-9 Faeroe Island rocks 267-8 lavas 440 Lower Series, Faroe Islands 222, 234 pseudobrookite 411 Tertiarylavas, Britain 217 pseudomorphs, saponite 70,124 reworking 279,368,369,407 pulaskite 207 Reykjanes Ridge 7-8, 21, 75, 157, 158 pull-apart tectonic setting 136, 137, 141 Rheinish Massif, uplift and volcanism 29 pumice layers 78 rheomorphism 367 Pyrenean orogenic belt 29 RhineGraben 25, 27 pyrite 78, 80, 257, 398 related to Alpine Orogeny 27, 29 pyroclastic breccia 365, 367, 369, 370-1,372, 374 subsidence of 29 unbedded 368 Rhum 375 pyroclastic deposits, NE Atlantic 415 central igneous (volcanic) complex 342, 385,444 pyroclastic rocks, silicic, British Tertiary Volcanic dating of 446 Province 365-77 siting determined by Long Loch Fault 445 pyroclastics 161 Central Series ultrabasic rocks 445 Wyville-ThomsonRidge 280 Eastern Layered Series 391 pyroxene 72, 124, 165, 210, 255,259, 299, 300, 305, Main Ring Fault 369 316 Northern Marginal Complex 369 brown 295 silicic pyroclastic rocks 369-71 Ti-rich 296 ultrabasic complex 391 titaniferous 276 Westerngranophyre 342, 343 pyroxenite 175 Rhum central volcano 445 alkali 436 Rhum layered complex 369 pyroxenization 391 rhyolite 344, 349, 373,432, 435,447,448 porphyritic 355-6 Tertiary, NE Ireland 355-7 Qajarsak granite 210 ridge emplacement, model of (Porcupine Median quartz 78, 80, 163,256, 316, 398 Volcanic Ridge) 320-2 poikilitic 78 ridge jump 102, I03, 251 quartz grains, floating 260 ridge-push, N Atlantic 30 quartz porphyry 368 ridge-push force 21,22 Arran 343 riebeckite microgranite 343 quartz syenite 205, 211,440 rift basins 52 intracratonic 309 rejuvenation of 430 Raasey Fault 386 rift model, NE Atlantic 157-8 recrystallization 370, 375 rift pillow 330 recrystallization effects, pyroclastic breccias 367 rift system, propagating/retreating 158 reddening 69, 299, 305,432, 445 rift zones tuffbeds 76 continental, controlled by older lineaments 430 REE, Kangerdlugssuaq region 170 northern E Greenland 434 REE enrichment 78 rifting 10, 50-1, 52, 145, 193, 235,248, 293,421 REE patterns, olivine tholeiite 276 late Jurassic, Norwegian-Greenland Sea 44-5 reflectors Mesozoic 434 ashmarker, NorthSea 412 rifting to drifting transition 66 fiat-lying 137 rifting process, N Atlantic 4-5, 7 reflector P, Wyville-Thomson Ridge 272 stepped 289 axial, formation of new oceanic lithosphere 436 subhorizontal 283 lateral 436 top-Cretaceous 244 Mesozoic 430 top-Palaeocene 244 ring-dykes 339, 351,357, 368, 372, 374, 376 regression 430 felsite 387 remagnetization, of early intrusions, Mull 340 Loch Ba 373 472 Index ring-faults/faulting 368,369, 440, 436 seafloor spreading 7, 21, 27, 103, 147, 330, 439 Ringvass~y-Loppa fault zone 144 abortive 293 Rockall Bank 225 along Senja fracture zone 422 Rockall-Faeroe microcontinent 27 early stages 120-1 Rockall-Faeroe Plateau, morphology of 115 basalt eruption 118 Rockall-Faeroe rift, volcanism 25 Greenland-Norwegian Sea 35-46, 325,421 Rockall-Hatton Bank, dipping reflectors 108 Greenland Sea RockallIsland, granitic 345 northern 136 Rockall margin 52 southern 144 Rockall microcontinent 442 Icelandic type 54 RockallPlateau 225,233,271 initiation of 43 flexured dipping reflectors 62--4 above sea-level 111 granite 345 NE Atlantic 112 igneous activity 442 Labrador Sea 431 subsidence of 27 cessation of 211 Rockall seastack 442 mid-Tertiary 112 Rockall Trough 115,225,230, 325, 345,448 westward shift 111-12 early Tertiary volcanic rocks 283-91,293-307 NE Atlantic 111 basaltic rocks, petrography and chemistry 295- oblique 157 300 onset of 132 dacitic rocks, petrography and chemistry 300-1 Faeroes-Greenland 235 isotope geochemistry 301-5 Goban Spur-Biscay continental margin 325 formation of 293 at passive margins 52-3 igneous activity 442 shallow marine 121 northern margin, sedimentary cover 271-2 subaerial 5, 37, 103, 121,123, 157 oceanic and transitional crust, formation of 243 and down-dip dipping reflectors 111 southern 271 early Tertiary, characteristics of 112 R~mer Fjord Formation 438 Phlmason model 103-5 Ros Gabbro (Killala Gabbro) 320, 322, 344 seafloor-spreading anomalies 90, 95, 108 Rosemary Bank 283,293 seafloor-spreading axes, phase of reorganization 330 R~snaes Clay Formation 397, 414 seafloor-spreadingsystems, oblique 136 ash layers 400 secular variation, geomagnetic 215,216, 219, 339 mineral composition of clay 398 incomplete averaging 219-20 Ryberg Fjord, E Greenland 203 sediment accumulation 423,430 sediment loading 291 sediment prism, Tertiary/Quaternary 273 sediment supply and sill intervals 248-9 St Kilda, faults 387 sedimentary basin formation, MacKenzie model 111 St Kilda intrusive complex 345, 346, 445 sedimentary basins 445 satite 411 asymmetric, Mesozoic 445 Sandfell laccolith 151 Midland Valley of Scotland, Antrim extension 445 Sandoy, Faeroe Islands 227,228 sedimentary sequence sandstone Jan Mayen Ridge 87 coastal, volcaniclastic 3t6 Tertiary, NE Rockall Trough 289 tuffaceous 278-9 sedimentary wedge, Cainozoic 135-136, 141 volcanogenic 439 sedimentation, Tertiary 421 reworked basaltic detritus 279 sedimentation and deformation, Tertiary, SW Barents Sandy Braes Seaand Svalbard 141-2, 144 central vent 446 sediments porphyritic obsidian 344 ash-bearing 254 sanidine 301,411 Cretaceous, marine and non-marine 432 saponite 124, 125 Cretaceous and lower Tertiary 437-8 Sarqat~t q~qgt central intrusive complex 432 glauconitic 132 schist, quartz-mica 80 hyaloclastite 287 ScoresbySund 166, 173, 218 inner-shelf 323 plateau basalt sequences 215 marine 90, 226, 316 Scoresby Sund Lavas, E Greenland 182,438 Mesozoic 438 Scoresby Sund-Shannon Island, igneous activity 386 434-6 Palaeogene 229 Scotland, NW continentalmargin 283 shallow-water 430 plateau basalts 289 sub-lava, compaction of 291 Scouriedykes 130,384 syn-rift 248 Scouriegneisses t30 Tertiary, WyvilIe-Thomson Ridge and Hebrides Seabight Igneous Centre 318,322, 325, 330 Shelf 278-9 Index 473

volcanic, Denmark, provenance and transport basic 254 mechanism 403 composite 342 volcanic-rich 312 developmentof 430 volcaniclastic 78, 80, 81,287, 312, 415, 417 doterite 201,260, 376, 448 North Sea Basin 407, 408-14 E Greenland 204-5 volcanogenic 312, 438,439, 442 petrography of 255-7 Wyville-ThomsonRidge 272 Faeroe-Shetland Channel 289 seismic marker internally differentiated 245 BarentsSea, tufflayer 141 intrusive changing to extrusive lavas 244 tuff deposits, early Tertiary 137 MORB-type rock 246, 248 seismic refractor, Faeroe Islands 226 muitiple injection 323-4 seismic unconformities 62 olivine-dolerite 254, 256 seismic velocities, lower crustal 5 picrite 289 Sele Formation 78, 253, 254, 255,260, 261,399-400, Porcupine Basin 319 408, 411 NE 316 selective contamination 362 quartz porphyry 343 selective diffusion 361 Tertiary 289, 291,319 Senja fracture zone I35, I36, 137, 141,144, 222, 421, tholeiitic 435 422, 423 silt winnowing 402 Senja Ridge 136, 141,142, 421,422 Skagerrak 431,447 inverted 135, 144 as ashlayer source 413 seriticization 165 igneous activity, evidence of ash layers 447 serpentine 299 Skaergaard intrusion 3, 162, 201,205,211,439-40 Sgurr of Eigg pitchstone 343,345, 346 Skagerrak volcano 445 Sgurr nan Gillean, Rhum 371 Skraenterne Formation 183, 187, 189, 438 shale 255,434 Skye 345, 346 indurated (Palaeozoic) 374 central intrusive (volcanic) complex 386, 444, 445 Kimmeridgian-Oxfordian 312 dyke swarms 383,384 lacustrine 226 flood basalts 217 shear intrusives, datesof 416 compressional 423 Main Lava Series 276 early Tertiary 422 persistent volcanism 445 dextral 384, 386 silicic pyroclastic rocks 366-9 differential 421,422 Tertiary igneous rocks 342 extensional and compressional 421 Tertiary volcanics 128 parallel, along Senja fracture zone 422 Skye lavas 445 pure 10 unradiogenic Pb 191 and dyke formation 382 Stieve Gullion central intrusive complex 344, 349, regional 361,386, 444 NE Greenland-Svalbard 135, 144 age of 357-8 Norwegian Sea-Eurasia Basin 136 cut by dextral strike-slip faults 387 transtensional, simple pyroclastic rocks 374-6 dextral 383-4 sheeted complex 350, 358 and dyke formation 383 temporaltrend, initial STSr/86Srratios 362 shear movement 421 Slieve Gullion Felsite 375 shear stress, and magma ridges 27 Slieve Gullion porphyritic granophyre 376 sheet intrusions 331 Slieve Gullion ring-dyke 376 shield morphology 322 SlyneFissures 319, 330, 331 shorelines, submerged 230 alignment 324 siderite/ankerite granules 256 periods of activity 322-4 sideromelane shards 78 Slyne Ridge 309 Sigmundur Seamount 115, 116 Slyne Trough 319 silica 257 Small Isles, the 342-3 silicified layers 397 dyke swarms 383,384, 385 sillcomplexes 112,289, 311,319 smectite 228, 275, 278,295,296, 299, 301,397, 401, Fastnet Basin 312 409 sheeted 257 chemicaI composition 398 sill emplacementepisodes, Faeroe-Shetland Basin dominance of 403 244-5 North Sea sedimentation rates 402 siII-sediment complexes volcanic origin possible 398 Einsele model 248-50 Sole Pit Basin 29 Sheridan model 250-1 Sortskaer, EGreenland 210 sill-swarms 430 source-rock melting 447 sills 227,343 sphene 411 474 Index

Spitsbergen Svalbard 222, 421 central basin 144 Svalbard Platform 135, 145 compressive shortening 422 Svartenhukpeninsula, lavas 432 fold and thrust belt 141,144 Sverdrup Basin, compression of 222 Spitsbergen Central Tertiary Basin 136, 421,422 swarm axes 381-4 spreading axis, propagating behaviour 157 Sydbrae area, rotation of 219 spreading centres 434 syenite 201,207, 210, 344, 436, 440, 447 Guaymas basin-type 248 agpaitic 441 Iceland 158 fayalite 211 and sheeted complexes 439 fayalite-hedenbergite 210 spreading ridge, S of Greenland-Senja fracture zone feldspathoidal 447 157 granite-quartz 210 spreading ridge crest, submergence 124 K-Ar analyses, Kangerdlugssuaq area 208-9 Sra na Creitheach, Skye, pyroclastic rocks 368 quartz 205, 211 stacking velocities 58 syenite veins, Kangerdlugssuaq area 210 Staffa magma type 80 syenogabbro 436 Stappen High 135, 136, 137 syn-rift sediments 248 extensional regime 421 inversion of 141,144, 145 stocks, granophyre 357 tachylyte 257 stoping 368-9, 436, 440 Taos Field volcanic plateau 80 Storfjorden Trough 423-5 Tardree Rhyolite 344 Strath na Creitheach, Skye 342 Tardree-Sandy Braes area 355-6, 373, 376 stress tectonic activity compressional 385 early Tertiary, NW Europe 25 shear 27 late Palaeozoic and Mesozoic 52 tensile 439 passive, N-S boundary zone, Iceland 151 2 tensional 27, 385,430, 439 reduction in 4I 7 stress fields 10, 381,384, 385-6, 386, 388 tectonic compensation 431 stretching prior to opening 53 tectonic movement, regional 381 strike-slip system 144 tectonic trend, Iceland, change in 151-2 strontium isotope/isotopic tectonism 430 data 355, 358 compressionaI 138, 141 geochemistry 301,361-2 extensional 325 Mourne Mountains granites 351-5 NE Atlantic margin 421 structural grain 384 related to igneous activity 325 Moine rocks 385 Rockall Trough 325 subductingslabs 16, 19 tensile stress 439 submarine fans 91 tension 10-11,248 subsidence 5, 7, 10, 51 2, 58, 131,144, 248, 330, 370, Davis Strait area 431 421,422, 423, 432, 435,438,439, 445 localized zones 386 axial 430 zones of Bjorn~ya Basin 42t migrating 386 central 375 preferential magma flow 386 crustal 386 tensional stress 27, 385,430 Faeroe Islands 229 reduction of 439 Faeroe-Shetland Channel 121 , reworked 255 initial, fault-defined 52 tephralayers, acidic 153 of intrusive centre 54 Tertiary Igneous Province of NW Scotland-N and lava edges 284, 287 Ireland-Faeroes-Greenland 3, 10-11 and lava extrusion 69 Tertiary tectonics, NW Europe 28, 29 margin 124 Th enrichment 71-2 North Sea Basin 416-17 Thanet Base Bed, Kent 260 post-Eocene 331 Thanet normal polarity zone 408 Rhine Graben 27 Thanet sands, Kent 376, 408, 409 Spitsbergen 421 thermal and pressure anomalies, N Atlantic and Tertiary 289 Greenland 21 thermal 54, 121,291 thermal anomalies two-phase, NE Rockall Trough 291 N Atlantic, influence on plate evolution 21 subsidence patterns, North Sea exploration wells 45 upper mantle 22 Suduroy, Faeroe Islands 227, 228,234 thermal boundary layer 16, 21 coal seams 226 thermal conduction 16 sulphide, brassy 256 thermal decay 330 surface deformation 19 thermal equilibration 7, 45 Index 475 thermal gradients 45, 46 basic 254 thermal metamorphism 241,256, 370, 375 petrography of 255 thermalsubsidence 54, 121,291 basic ashfall, K-Ar whole-rock dating 259 thermal thinning 330 Danian sediments 431 tholeiite 70, 125, 163, 339, 447 intrusive 369 depleted 278 lapilli-tuff 369, 370 Faeroe Islands 230 lithic and crystal 369, 370 Fe-Ti 413 nephelinitic 438 high Fe-Ti 280 North Sea 25 high-Ti 233 primary 255 low alkali 299 pyroclastic, early Eocene 271 low- and high-Ti 438, 439 pyroclastic airfall 312 Mg-poor 433, rhyolitic 373 Mg-rich, W Greenland 432-3 silicic 367, 372, 373, 376 N-MORB type 443 silicic airfall 367 oceanic 130 tholeiitic, high Ti 265 olivine 233, 245, 296, 305,442, 446 trachytic 373 low-Ti 233 vitric, basaltic 65 picritic 433 vitroclastic 124 Ti-poor 442 water-lain 161 thomsonite 295, 296, 299 welded 370, 373 Thulean Volcanic Province 429 west of Shetland Islands 263 Ti-augite 411 tuff-agglomerate zone, Faeroe Islands 229-30, 442 Ti-magnetite 124, 128 correlated with Balder Formation 266-7 titanomagnetite 257,274, 278,296, 299, 300 local facies, Vestmanna Member 27 low-and high-Ti 216 tuffbeds 69, 128 topographic inversion 5 Upper Series, V~ring Plateau 76-8 topographic swell, N Atlantic 16-17 tuffmarker 143 topography, influence on anomaly field 148 tutiisite 369, 371,373, 375 Tow Valley Fault 386, 388 trace element enrichment pattern Lower Series and tholeiitic dykes, Voting Plateau 76, 79 U-depletion 128, 129, 130 stratichemical units, Upper Series, Voring Plateau Ubekendt Ejland 432 73 lamprophyres 434 trace element patterns, Lower Series lavas, unconformities 141,315,322, 430, 438 Voring Plateau 79-80 angular trace elements, olivine tholeiite 276 basin margin 272, 273 trachybasalt 432 Oligocene 141 trachyte 342, 368, 432 Austrian 325 biotite 372 Cretaceous, basal 317 silicified 366 lateKimmerian 309, 31-7, 321 Trail1121 doming of 320 central intrusive complexes 436 syn-rift 330 sills 435 late Kimmeridgian 312 transgressive/regressive cycles, North Sea 407 Oligocene, basal 331 transpression 136, 144 underplating 44,130 Spitsbergen Fold and Thrust Belt 144 by upper mantle partial melts 38 transtension 136 continental 441 ,, dextral 387 crustal 386 troctolite 391 Jurassic 45 Trolleland fault zone 144 uplift 141,386, 422 Troms-Finnmark Platform 421 Campanian 119 Troms~Basin 135, 141,144 domal 441 extensional 421 and mantle hot-spots 10 thickening sedimentary sequence 141 mid-Kimmerian 325 tuffmarker 143 post-separation 441 Trondelag Platform 52 regional 386,441 tuff 144, 227,235, 260, 287, 291,316, 366, 373, 376, Upper Basalt Formation, Antrim 278,306, 344, 373, 412, 432, 434 446 air-fall i25 Upper Basalt Formation, Faeroe Islands 119,227, ashflow 367,372 228-9, 261 Balder Formation 280 E and SW Shelf 229 basaltic 124, 368 upper mantle flow 19 476 Index

Upper Plateau Basalts, E Greenland 201 North Sea, two phases of explosive volcanism 417 Scoresby Sund 203 volcaniclastics 123, 124, 323 Upper Plateau lavas, E Greenland 435-6 NE Porcupine Basin 322, 325 Upper Series, Voting Plateau 51, 59, 65-6, 443 volcanics basal reflector 65 acid, Tardree 343 lithology and petrography 69-76 intermediate comparison with NE Atlantic magmatic continental affinities, western Voring Plateau 59 provinces 75-6 Voring Plateau 65 petrology of the tholeiitic basalts 70-5 rhyolite 255 sediments 76-8 volcanism Upper Series basalts, Faeroe Islands 218,222, 247, ~tctive 386 302-3,441,442 alkaline, inland 441 upwelling, passive 53 along line of active rifting 200 Uttental Plateau, THOL-2 dyke swarms 165 axial, increase in 330 basaltic 280,431 basic, rifting-related, Torridonian 130 V~gar, Faeroe Islands 227 basinal 330 Vandfaldsdalen Formation 163, 183, 186, 192, 193, British 414--16 203, 266 British Tertiary Volcanic Province, commencement isotope geochemistry of the lavas 186-7 of 430 isotopic trends 186 Cainozoic 137, 141 tholeiite 268 Cape Verde Rise 8 velocity discontinuities, upper crust 38, 40 central type 415 velocity structure cessation of, British Tertiary Volcanic Province dipping reflectors, E Greenland 105-10 417 upper crustal 108, 110 continental 111 vent infill 365, 366, 372, 374 continental-rift margin 7 vents, retreating 5 Cretaceous 429-30 vertical movement, Bjornoya marginal high 137 Danian 315-16 vesiculation 375 early Tertiary 49, 225, 447 Vestmanna drill-hole 227 continental 16, 20 VestmannaMember 227,230 N Atlantic 3-11 Vidoy, Faeroe Islands 228 North Sea Basin 407-18 Vidoy Member 227, 230 western Barents Sea margin 135-45 Viking Graben 388 E Greenland 266 sedimentation rate 402, 403 Eocene extrusive 50 viscosity, in the mantle 16 explosive 260, 365, 366, 372, 373, 376, 413, 414 viscous drag 376 adjacent to North Sea Basin 414 volatile release 369 increase of in Iceland 153 volcanic centres 230 extrusive, Skye 366 explosive 10 Faeroe Islands 235, 261 volcanic complexes, Iceland 150-1, 151-2 early termination of 236 volcanic debris 255 switch to Greenland 235 volcanic glass 397,408 Faeroes region, evidence for 263-8 volcanic margins, N Atlantic 3 fissure 439, 446 volcanic markers Hebridean, and ash deposition 445 Jan Mayen Ridge (reflector F) 85, 92 high-Ti type 235 possible interpretations 90-1 intraplate, E Greenland 157-8 volcanic peaks (Bjornoy marginal high) 137, 141 Jurassic 320 volcanic productivity rate 104 major regional 255 volcanic provinces, Jan Mayen Ridge 87, 90-1 marginal 147 volcanic source mid Tertiary 145 seaward migration of 102 model for lateral shift 235 up-dip or down-dip 102-3 N Atlantic 416-17 volcanic vents 375 NE Atlantic 173 volcanic zone 148 Palaeogene: sedimentary record in Denmark 395- volcaniclastic debris, reworked 253 403 volcaniclastic flows, Varing Plateau 65 rift-related 235 volcaniclastic sand Rockall, western 132 basaltic 409 silicic pyroclastic 377 Moray Firth 415 subaerial 111 volcaniclastic sediments submarine 110 early Palaeogene, distribution of in NW Europe syn-rift 3 410 Tertiary, Kangerdlugssuaq region 161-77 Index 477

thoteiite basalt 434 Werner Bjerge central intrusive complex 210, 436 Thulean 253 Wessex Basin, inversion structures 29 volcanoes West Netherlands Basin 29 central 431,439, 440, 443 West Spitsbergen Fold Belt 421 central-vent 435,447 orogenesis and deformation 422 fissure 320, 430, 434, 437 Western BarentsSea Basin, rifted 421 nephelenitic 441 Western Red Hills, Skye 260, 342, 346, 368 Skagerrak 400 emplacement of granites 415-16 Voring Basin 52 Wetzeliella astra zone 400 sill intrusion 248 Wetzelietla hyperacantha zone 266 Voring passive margin 6-7 Wetzeliella meckelfeldensis zone 400 early Cainozoic evolution 53--4 Widemann Fjord, E Greenland 203,205 Voring Plateau 4-5, 49, 95, 307, 448 Wilson Cycles 27 and conjugate Greeniand margin 38, 40 Wolf Rock-Epsom Shoal igneous association 325 correlation with NE Greenland plateau basalts Wollaston Forland 81,434 80-1 wrench tectonics, Svalbard-Barents Shelf and NE dipping reflectors, MORB-type basalt 132 Greenland 144 divergent-arcuatereflectors 58-9, 61, 62, 65-6 Wyville-Thomson Ridge 116,229, 271,283,289 igneous activity 442-3 sediments 272 and landward Norwegian margin, structure of 37 models for dipping reflectors 52-4 origin of Palaeogene volcanic sequence 69-81 Lower Series lavas, lithology and petrography 78-80 375 Upper Series lavas, lithology and petrography basalt 205, 210 69-76 gabbro 210 Upper Series sediments 76-8 mantle 192,447 underlain by upper continental crust basement 80 Voring Plateau continental margin 49 Voring Plateau Escarpment 5, 35 V~ring Plateau lavas, chemical affinities of 75-6 Ymir Ridge 229, 283,289 Voting Plateau marginal bigh 51,135, 443 V~ring sedimentary basin 49

cement 255,259 wairakite 257 77, 125, 163, 165,257, 278, 301,403 weathering heulandite-clinoptilolite type 397 deep, of silicic rocks 373 zoning 165 lateritic 446 Zuider Zee depression, aseismic 29