List of geological faults of Wales

Last updated

This is a list of the named geological faults affecting the rocks of Wales. See the main article on faults for a fuller treatment of fault types and nomenclature but in brief, the main types are normal faults, reverse faults, thrusts or thrust faults and strike-slip faults. Many faults may have acted as both normal faults at one time and as reverse or thrust faults at another and may or may not have also incorporated some degree of strike-slip movement too. Fault zones, fault belts and fault complexes typically describe assemblages of faults which have a common origin and history and whose alignments tend to be sub-parallel to one another.

Contents

There are also a number of 'disturbances', notably in South Wales. These linear features are a combination of faults and folds - the relative importance of faulting and folding varying along the length of each disturbance.

Key to tables

Alphabetical lists of faults

A

Fault nameOS map refCountyBGS map sheetbook references
Aber Dinlle Fault GwyneddBrenchley & Rawson 2006
Aber FaultGlamorganshireE&W 248
Aber Richard FaultE&W 194; 210
Aberbeeg FaultMem E&W 232
Aberdaron FaultGwyneddE&W 133
Abergwesyn FaultE&W 196, 212
Abertillery FaultE&W 249Mem E&W 232
Abertridwr FaultGlamorganshireE&W 249
Acorn FaultE&W 230
Afon Banwy FaultPowysE&W 150
Afon Ganol FaultClwydMem E&W 95/107
Afon Saint FaultGwyneddE&W 133
Allt y Crib FaultE&W 163
Allt y Grug FaultE&W 230
Alyn Valley FaultE&W 108
Anafon FaultGwyneddE&W 106
Arthog - Caerdeon FaultE&W 149
Axton FaultFlintshireE&W 96

B

Fault nameOS map refCountyBGS map sheetbook references
Bala - Llanelidan Fault Smith et al. 2005
Bala Fault E&W 135; 136
Bala Fault ZoneUK (south) 625K
Beddgelert Fault GwyneddE&W 119
Beech Hill FaultMonmouthshireUsk-Cwm:25K
Belmont FaultClwydMem E&W 95/107
Benton Fault PembrokeshireE&W 228Brenchley & Rawson 2006
Berach FaultE&W 230
Berw Fault AngleseyBrenchley & Rawson 2006
Berw Fault ComplexAngleseyBrenchley & Rawson 2006
Bethel FaultGlamorganshireE&W 247
Bettws FaultE&W 230
Bettws Newydd FaultMem E&W 232
Blaenavon FaultMonmouthshireE&W 232
Blaenhirwaun ThrustE&W 230
Blaen Onneu FaultE&W 232
Bodafon ThrustAngleseyBrenchley & Rawson 2006
Bodelwyddan FaultDenbighshireE&W 95; 107Mem E&W 95/107
Box FaultGlamorganshireE&W 247
Bristol Channel Fault Zone Bristol Channel
Bronnant Fault CeredigionE&W 178; 210; 211
Bronnant Fault Zone CeredigionE&W 194; 195
Brothers FaultGlamorganshireE&W 247
Brwynd OverthrustE&W 163
Bryn Eglwys FaultE&W 120Brenchley & Rawson 2006
Bryn Morgan ThrustE&W 230
Bryn Posteg FaultE&W 164
Bryn Rhys FaultClwydMem E&W 95/107
Brynderi FaultMonmouthshireMem E&W 233/250
Bryneglwys Fault E&W 121
Bryngwili FaultE&W 230
Bryngwyn FaultGlamorganshireE&W 230; 247
Bryn-y-maen FaultDenbighshireE&W 95
Bwlchgwyn FaultE&W 108
Bylchau FaultDenbighshireE&W 107Mem E&W 95/107

C

Fault nameOS map refCountyBGS map sheetbook references
Cae Parc FaultGlamorganshireE&W 247
Caerdeon Bodlyn FaultMerionethshireE&W 135
Caergwrle FaultE&W 108
Caerleon FaultMonmouthshireE&W 249; Usk-Cwm:25K
Caerphilly FaultGlamorganshireE&W 249
Camdwr FaultE&W 163
Capel Garmon FaultClwydE&W 107Mem E&W 95/107
Cardigan - Fishguard Fault BeltPembrokeshireE&W 210
Carmel Fault (Powys)PowysE&W 179
Carmel Fault (Carmarthenshire)CarmarthenshireE&W 230
Carmel Head Thrust UK (south) 625KBrenchley & Rawson 2006
Carreg Maen Taro FaultE&W 232
Carrog Valley FaultCeredigionE&W 178
Cascade OverthrustE&W 163
Castell FaultE&W 163Mem E&W 165/151
Cefn FaultClwydMem E&W 95/107
Cefncynfal FaultPowysMem E&W 165/1051
Cefn Bryn ThrustGlamorganshireE&W 246
Cefn Crib FaultGlamorganshireE&W 249
Cefn FaultE&W 107
Cefn Garw FaultMonmouthshireMem E&W 233/250
Cefn Ila FaultMonmouthshireUsk-Cwm:25KE&W 232
Cefnamwlch-Rhiw FaultGwyneddE&W 134
Ceibwr Bay Fault E&W 193
Ceidio FaultAngleseyBrenchley & Rawson 2006
Ceunant FaultE&W 149
Chapel FaultE&W 231
Chepstow FaultMonmouthshireMem E&W 233/250
Church Stretton Fault System Brenchley & Rawson 2006
Church Stretton Fault Zone E&W 213Mem E&W 165/151
Cilfeigan FaultMonmouthshireE&W 249; Usk-Cwm:25K
Claerwen Fault E&W 179
Clochaenog FaultClwydMem E&W 95/107
Clwyd Fault Smith et al. 2005
Clydach Bridge FaultMonmouthshireE&W 232
Clywedog FaultE&W 164
Clytha FaultE&W 232
Coalbrook FaultE&W 230
Coed Hir FaultE&W 231
Coed Ithel FaultMonmouthshireMem E&W 233/250
Coedycerrig FaultE&W 232
Coed-y-paen FaultMonmouthshireE&W 249; Usk-Cwm:25K
Conwy Valley Fault/Conway Valley FaultGwyneddE&W 106Mem E&W 95/107
Copper Works FaultGlamorganshireE&W 247
Cors-bol FaultAngleseyBrenchley & Rawson 2006
Craig Twrch FaultE&W 212
Craiglaseithin Fault GwyneddE&W 135/149
Craignant - Milton FaultSmith et al. 2005
Craignant FaultSmith et al. 2005
Craig-y-beri FaultE&W 137
Craig-y-glyn FaultE&W 137
Creigydd FaultMonmouthshireE&W 249; Usk-Cwm:25K
Cribarth Fault E&W 213
Crick FaultMonmouthshireMem E&W 233/250
Cross Ash FaultMonmouthshireMem E&W 233/250
Crychan FaultPowysE&W 196, 213
Crychan Fault BeltE&W 213
Cwm Cayo Brook FaultMonmouthshireMem E&W 233/250
Cwm Cynnen FaultE&W 211
Cwm Dockin FaultE&W 165
Cwm Dwfnant FaultE&W 196
Cwm Earl FaultE&W 165
Cwm Felin FaultGlamorganshireE&W 247
Cwm Llwyd Fault E&W 230
Cwm Pennant Fault Brenchley & Rawson 2006
Cwm Pit FaultGlamorganshireE&W 247
Cwm Sylwi FaultE&W 149; 163
Cwmcarvan FaultMonmouthshireMem E&W 233/250
Cwmdockin FaultPowysMem E&W 151/165
Cwm-dows FaultGlamorganshireE&W 249
Cwmgwineu FaultGlamorganshireE&W 247
Cwmllynfell FaultE&W 230
Cwm-Mawr FaultE&W 196
Cwmmawr ThrustE&W 230
Cwmneol FaulE&W 231
Cymmer FaultGlamorganshireE&W 248
Cynheidre ThrustE&W 230
Cynllaith FaultE&W 137

D

Fault nameOS map refCountyBGS map sheetbook references
Daren Ddu FaultGlamorganshireE&W 249
Daron FaultGwyneddE&W 133
Denbigh FaultClwydE&W 107Mem E&W 95/107
Dinas Fault (Powys)PowysE&W 231
Dinas Fault (Glams)GlamorganshireE&W 248
Dinorwic FaultGwyneddE&W 106
Dip Fach FaultE&W 231
Dolforwyn FaultE&W 165Mem E&W 151/165
Dolwar FaultPowysE&W 150
Dowlais Fault (Mons)MonmouthshireE&W 231; 232
Dowlais Fault (Glams)GlamorganshireE&W 249
Duffryn FaultGlamorganshireE&W 230, 247
Dulas FaultE&W 196
Dulas Gap FaultDenbighshireE&W 95; 107Mem E&W 95/107
Dyffryn Maelor FaultClwydMem E&W 95/107
Dyfi Valley FaultPowysE&W 150
Dyfnant FaultPowysE&W 150
Dyfngwm FaultE&W 164
Dylife Esgairgaled FaultE&W 164
Dylife FaultE&W 164
Dynant FaultE&W 230
Dysynni FaultE&W 149
Dyto FaultClwydMem E&W 95/107

E

Fault nameOS map refCountyBGS map sheetbook references
East Llangerniew FaultClwydE&W 107Mem E&W 95/107
Efailnewydd FaultGwyneddE&W 134
Eglwysbach FaultClwydMem E&W 95/107
Energlyn FaultGlamorganshireE&W 249
Erroxhill FaultPembrokeshireE&W 228

F

Fault nameOS map refCountyBGS map sheetbook references
Felin Arw FaultGlamorganshireE&W 248
Ferry FaultGlamorganshireE&W 247
Flint FaultE&W 108
Forge OverthrustE&W 149; 163

G

Fault nameOS map refCountyBGS map sheetbook references
Gadlys FaultGlamorganshire E&W 231; 248
Gardeners FaultGlamorganshireE&W 230; 247
Garth - Llanwrtyd Fault BeltE&W 212
Garth FaultE&W 196, 213
Garth Ferry FaultAngleseyBrenchley & Rawson 2006
Garth Hill OverthrustGlamorganshireE&W 249
Gelli FaultGlamorganshireE&W 249
Gelligaer FaultGlamorganshireE&W 249
Gelli-goch OverthrustE&W 149; 163
Giant's Grave FaultGlamorganshireE&W 247
Glan Hafren FaultE&W 165Mem E&W 151/165
Glanalders FaultE&W 179
Glandyfi FaultE&W 163
Glaslyn Valley FaultBrenchley & Rawson 2006
Glyn Ceiriog FaultE&W 121
Glyn FaultMonmouthshireE&W 249; Usk-Cwm:25K
Glyn Valley FaultE&W 135
Glyn Wallis FaultE&W 230
Glyncorrwg FaultGlamorganshireE&W 231; 248
Gnoll FaultGlamorganshireE&W 247
Gop FaultFlintshireE&W 95Mem E&W 95/107
Gors FaultGlamorganshireE&W 230, 247
Gorsedd Bran FaultClwydMem E&W 95/107
Gorseinon FaultGlamorganshireE&W 247
Great Ewloe FaultE&W 108
Greenland FaultMonmouthshireE&W 232
Gresford FaultE&W 121
Grib FaultE&W 230
Groes FaultClwydE&W 107Mem E&W 95/107
Grovesend FaultGlamorganshireE&W 230; 247
Guilsfield FaultPowysE&W 150, 151Mem E&W 151/165
Gwaynynog FaultClwydE&W 107Mem E&W 95/107
Gwern-ddu FaultMonmouthshireMem E&W 233/250
Gwespyr FaultFlintshireE&W 96
Gwili FaultGlamorganshireE&W 230, 247
Gwrych Castle FaultDenbighshireE&W 95; 107Mem E&W 95/107
Gyrnos FaultE&W 231

H

Fault nameOS map refCountyBGS map sheetbook references
Hafan FaultE&W 163
Hawarden FaultE&W 108
Hendre FaultE&W 230
Highgate FaultPowysE&W 164; 165Mem E&W 151/165
Hirwaun No 1 FaultE&W 231
Hirwaun No 2 FaultE&W 231
Hirwaun No 2a FaultE&W 231
Hirwaun No 3 FaultE&W 231
Hudnalls FaultMonmouthshireMem E&W 233/250

I,J,K

Fault nameOS map refCountyBGS map sheetbook references
Itton FaultMonmouthshireMem E&W 233/250
John Grey's FaultGlamorganshireE&W 247
Keepers Lodge FaultE&W 230
Kilkenny FaultGlamorganshireE&W 231; 249
King's Wood FaultMonmouthshireMem E&W 233/250
Kinmel Park FaultDenbighshireE&W 95Mem E&W 95/107

L

Fault nameOS map refCountyBGS map sheetbook references
Leeswood FaultE&W 108
Little Mill FaultE&W 232
Llanbadoc FaultMonmouthshireE&W 232; Usk-Cwm:25K
Llancayo FaultMonmouthshireE&W 233Mem E&W 233/250
Llandrindod - Pen-y-waun Fault BeltE&W 213
Llandyfan FaultE&W 230
Llandynan FaultE&W 121
Llanegryn FaultE&W 149
Llanelidan FaultE&W 121
Llanerchyraur FaultE&W 164
Llanerfyl FaultPowysE&W 150
Llanfabon FaultGlamorganshireE&W 231; 249
Llanfrechfa FaultMonmouthshireE&W 249; Usk-Cwm:25K
Llangattock FaultMem E&W 233/250
Llanglydwen FaultE&W 210; 211
Llangollen - Llantysilio - Aqueduct FaultSmith et al. 2005
Llangollen FaultE&W 121
Llangwm FaultMonmouthshireMem E&W 233/250
Llangynidr FaultMem E&W 232
Llanhilleth FaultGlamorganshireE&W 249
Llannefydd FaultClwydE&W 107Mem E&W 95/107
Llanrhaeadr FaultClwydE&W 107Mem E&W 95/107
Llantysilio FaultE&W 121
Llanvair Discoed FaultMonmouthshireMem E&W 233/250
Llanvair FaultMonmouthshireE&W 250
Llanvapley FaultMem E&W 232
Llanvihangel FaultMonmouthshireMem E&W 233/250
Llanwonno FaultGlamorganshireE&W 248
Llanwrtyd FaultE&W 196
Llanwrtyd FaultE&W 213
Llechwedd FaultE&W 164
Llethir FaultE&W 230
Llety Wilws FaultE&W 230
Llwyn Celyn FaultE&W 230
Llwyn FaultE&W 165
Llyfnant FaultE&W 163
Llysfaen FaultDenbighshireE&W 95Mem E&W 95/107
Longoaks FaultGlamorganshireE&W 247
Lunnon FaultGlamorganshireE&W 247

M

Fault nameOS map refCountyBGS map sheetbook references
Maen FaultClwydMem E&W 95/107
Maes-gwyn (or Maes Gwyn) FaultClwydE&W 107Mem E&W 95/107
Marian Ffrith (or Marianffrith) FaultFlintshireE&W 95Mem E&W 95/107
Mathern FaultMonmouthshireMem E&W 233/250
Mawddach FaultE&W 149
Melai FaultClwydMem E&W 95/107
Menai Strait Fault System Brenchley & Rawson 2006
Merthyr Church FaultGlamorganshireE&W 231; 249
Meusydd FaultE&W 230
Minera Fault BeltE&W 121
Minffordd FaultBrenchley & Rawson 2006
Mochras Fault MerionethshireE&W 135; 49Brenchley & Rawson 2006
Moelfre FaultMerionethshireE&W 135
Moel-Gilau FaultGlamorganshireE&W 248
Montgomery FaultPowysMem E&W 151/165
Morfa FaultGlamorganshireE&W 247, 248
Morlais FaultGlamorganshireE&W 247
Mount Pleasant FaultE&W 230
Mynydd Bach FaultE&W 195
Mynydd Bodrochwyn FaultClwydMem E&W 95/107

N

Fault nameOS map refCountyBGS map sheetbook references
Nant Cerrig FaultClwydMem E&W 95/107
Nant Dyar FaultMem E&W 232
Nant Marl FaultE&W 230
Nant y Fedw FaultE&W 196
Nant-Figillt FaultE&W 108
Nantmor FaultGwyneddE&W 119
Nantygwrdy FaultE&W 164
Nantyricket FaultE&W 164
Nedern FaultMonmouthshireMem E&W 233/250
Nercwys - Nant-Figillt Fault ZoneE&W 108
New House ThrustE&W 165
Newcastle FaultMonmouthshireMem E&W 233/250
Newlands ThrustGlamorganshireE&W 247, 248
Newmarket FaultClwydMem E&W 95/107
Newton FaultGlamorganshireE&W 247
Newmarket FaultFlintshireE&W 95
Newport Sands FaultE&W 193; 210
Nicholaston FaultGlamorganshireE&W 247

O

Fault nameOS map refCountyBGS map sheetbook references
Ochr-y-cefn FaultClwydMem E&W 95/107
Ogof Cadno FaultE&W 193
Ogof FaultE&W 163
Olway Brook FaultMonmouthshireMem E&W 233/250

P,Q

Fault nameOS map refCountyBGS map sheetbook references
Palleg FaultE&W 230
Palmer's Lake OverthrustsPembrokeshireE&W 244/5
Pant FaultDenbighshireE&W 95Mem E&W 95/107
Pant-y-fotty FaultClwydMem E&W 95/107
Paper Mill FaultE&W 108
Parc Postyn FaultClwydMem E&W 95/107
Pared FaultGwyneddE&W 133
Parwyd FaultGwyneddE&W 133
Pendaren FaultGlamorganshireE&W 249
Penffordd FaultPembrokeshireE&W 210
Pengam FaultGlamorganshireE&W 249
Pennal FaultE&W 149; 150; 163
Penrhiwfelen FaultGlamorganshireE&W 247
Penterry FaultMonmouthshireMem E&W 233/250
Pentre Clwydau FaultE&W 231
Pentre Felin FaultClwydMem E&W 95/107
Pentre Llanharan ThrustGlamorganshireE&W 248
Pentremawr Lag FaultCarmarthenshireE&W 229
Pentre Tafarn-y-fedw FaultClwydMem E&W 95/107
Pentwyn Fault (Mons)MonmouthshireE&W 249
Pentwyn Fault (Glams)GlamorganshireE&W 249
Pen-y-castell FaultGlamorganshireE&W 231, 248
Penydarren FaultE&W 231
Pen-y-Fan FaultMonmouthshireE&W 232
Pen-y-llan FaultMonmouthshireE&W 249; Usk-Cwm:25K
Pen-y-parc FaultMonmouthshireE&W 249; Usk-Cwm:25K
Plas Isaf FaultGlamorganshireE&W 247
Pont Morlais FaultE&W 230
Pontarsais FaultE&W 212
Pont-y-ddol FaultClwydMem E&W 95/107
Pontypool Road FaultMonmouthshireE&W 232
Port Eynon ThrustGlamorganshireE&W 246
Portskewett Hill FaultMem E&W 233/250
Prestatyn FaultClwydE&W 95Mem E&W 95/107
Pwllau Bach FaultE&W 231
Pwllmawr FaultGlamorganshireE&W 247
Pwll-meyric FaultMonmouthshireMem E&W 233/250

R

Fault nameOS map refCountyBGS map sheetbook references
Ramsey FaultPembrokeshireE&W 209
Rassau FaultMem E&W 232
Reservoir FaultMonmouthshireMem E&W 233/250
Rhadyr FaultMonmouthshireUsk-Cwm:25KMem E&W 232
Rhaiadr FaultE&W 137
Rhiw FaultGlamorganshireE&W 249
Rhiw Gwraidd FaultE&W 179
Rhobell FractureBrenchley & Rawson 2006
Rhos FaultGlamorganshireE&W 231; 232; 249
Rhuallt FaultFlintshireE&W 95Mem E&W 95/107
Rhydding FaultGlamorganshireE&W 230; 247
Rhyd Sion Wynn FaultClwydMem E&W 95/107
Rhyd-y-creua FaultClwydMem E&W 95/107
Rhymney FaultMem E&W 232
Ritec Fault PembrokeshireBrenchley & Rawson 2006
Road Uchaf Fault?Brenchley & Rawson 2006
Rock Park FaultE&W 196
Rockfield FaultMonmouthshireMem E&W 233/250

S

Fault nameOS map refCountyBGS map sheetbook references
Sarn-Abersoch ThrustGwyneddE&W 134
Sawdde FaultE&W 212
Severn Valley Fault BeltE&W 151Toghill P. 2006
Siamber Wen FaultDenbighshireE&W 95; 107Mem E&W 95/107
Sirhowy FaultMonmouthshireE&W 232
Six Pit FaultGlamorganshireE&W 247
Soflen FaultClwydE&W 107Mem E&W 95/107
Soughton FaultE&W 108
St Arvans FaultMonmouthshireMem E&W 233/250
St Brides FaultMonmouthshireMem E&W 233/250
Stradey FaultCarmarthenshireE&W 229
Strumble Head FaultPembrokeshireE&W 210
Swansea FaultGlamorganshireE&W 247
Swansea Valley Fault E&W 213
Syddyn FaultCarmarthenshireE&W 229

T

Fault nameOS map refCountyBGS map sheetbook references
Tafalog FaultPowysE&W 150
Taipellaf FaultClwydMem E&W 95/107
Talgarth FaultMonmouthshireMem E&W 233/250
Tal-y-coed FaultMonmouthshireMem E&W 233/250
Tal-y-llyn FaultE&W 149
Tanant FaultE&W 137
Teifi FaultE&W 212
Tintern FaultMonmouthshireMem E&W 233/250
Tirdonkin FaultGlamorganshireE&W 247
Tonfannau FaultE&W 149
Trafle FaultGlamorganshireE&W 247
Trawsfynydd - Cwm Bowyd FaultBrenchley & Rawson 2006
Trawsfynydd FaultMW&M:250K, E&W 135
Tredegar FaultMonmouthshireE&W 231; 232
Tre-fal-du FaultMonmouthshireMem E&W 233/250
Trelleck Common FaultMonmouthshireMem E&W 233/250
Trelleck FaultMonmouthshireMem E&W 233/250
Tremadog Thrust ZoneBrenchley & Rawson 2006
Tre-'r-ddol FaultE&W 163
Trevethin FaultGlamorganshire, MonmouthshireE&W 232; 249
Trinant FaultGlamorganshireE&W 249
Tumble FaultE&W 230
Tweedle FaultE&W 231
Twrch Fechan FaultE&W 230
Twyn Sych FaultE&W 231
Ty Llwyd FaultE&W 230
Ty Mawr FaultClwydMem E&W 95/107
Tyn-y-caeau Fault (Denb)DenbighshireE&W 95Mem E&W 95/107
Ty'n-y-caeau Fault (Mons)MonmouthshireE&W 249; Usk-Cwm:25K

U,V

Fault nameOS map refCountyBGS map sheetbook references
Upper Artro FaultMerionethshireE&W 135
Usk FaultMonmouthshireMem E&W 233/250
Vale of Clwyd Fault DenbighshireE&W 121; 95Mem E&W 95/107
Van FaultE&W 164

W,X,Y,Z

Fault nameOS map refCountyBGS map sheetbook references
Warren FaultE&W 230
Welsh Borderland Fault Smith et al. 2005
Welsh Borderland Fault System UK (south) 625KBrenchley & Rawson 2006
Wenallt FaultE&W 164
Werf FaultE&W 231
West Llangerniew FaultClwydE&W 107Mem E&W 95/107
Weston Madoc FaultE&W 165
Wonastow FaultMonmouthshireMem E&W 233/250
Wrexham FaultE&W 121
Yspytty Ifan FaultE&W 120
Ystwyth FaultE&W 179Mem E&W 151/165

List of Disturbances

The following named features comprise both faulting and folding;

table of named disturbances
Disturbance nameOS map refCountyBGS map sheetbook references
Caerbryn DisturbanceCarmarthenshireE&W 230
Carreg Cennen Disturbance CarmarthenshireE&W 230
Clun Forest Disturbance
Cribarth Disturbance PowysE&W 230, 231
Llandyfaelog DisturbanceCarmarthenshireE&W 231
Llannon (or Llanon) DisturbanceCarmarthenshireE&W 230
Neath Disturbance E&W 231
Pontyclerc DisturbanceCarmarthenshireE&W 230
Saron DisturbanceCarmarthenshireE&W 230
Trimsaran Disturbance

See also

References

Maps

Books