244:
67:
337:
386:
The coastline of Kent is continually changing, due to uplift, sedimentation, and marine erosion. The Isle of Thanet was till recently (AD 960) an island, formed around a deposit of chalk. The channels silted up with alluvium. Similarly Romney Marsh and
Dungeness have been formed by accumulation of
188:
The chalk comes in three layers: the upper layer, about 500 feet thick, is a pure white limestone bedded and jointed with localised masses of flint (ideal for cement); the middle layer, about 170 feet thick, is a compact white chalk occasionally hard enough for building; the lower layer, about 170
655:
Note that the lowermost three units were formerly known by the names 'Ashdown Beds', 'Wadhurst Clay' and 'Tunbridge Wells Sand' and together constituted the 'Hastings Beds', a name no longer formally recognised by geologists but nevertheless common in the literature. The old name 'Wealden Series'
267:
are built on the greensand. Greensand comes in four layers: the
Folkestone Beds 60–250 ft thick; The Sandgate Beds 5–120 ft thick; the Hythe beds 60–350 ft thick and Atherfield Clays 15–50 ft thick. The soil of the greensand is quite varied, ranging from fertile to fairly
128:
and ridges and valleys resulted across Kent and Sussex due to the exposed clay eroding at a faster rate than the exposed chalk, greensand and red sandstone and normal sandstone. The following ridges and the valleys have formed across Kent, listed from north to south:
100:
dome, a denuded anticline across Kent, Surrey and Sussex, which was the result of uplifting caused by the Alpine movements between 10-20 million years ago. The dome was formed of an upper layer of
368:
within the
Westphalian Sandstone are deep (below 244m - 396m) and subject to flooding. They occur in two major troughs, which extend under the English Channel where similar coalfields are sited.
251:
Greensand is a calcareous sandstone containing an uneven distribution of the mineral glauconite, giving the sandstone a greenish tinge. On exposure to the air this oxidises into a yellow stain.
478:
were worked in the past from the upper, middle and lower Coal
Measures. Fourteen seams are named sequentially downwards as Kent No 1, Kent no 2 etc. The Lower Coal Measures lie
333:
meaning simply woodland. Much of the area remains today densely wooded; where there are also heavy clays the tracks through are nearly impassable for much of the year.
96:
The major geographical features of the county are determined by a series of ridges running from west to east across the county. These ridges are the remains of the
943:
1165:
887:
British
Geological Survey 1:50,000 scale geological map series sheets (England and Wales) 270-274, 287-290, 303-306 & 320/21 and accompanying memoirs.
918:
849:, of Aeolian origin, i.e., windblown, are common in east Kent, especially on the northern slopes of the Downs where they are known as brickearths.
530:. These are in turn overlain by the sandstones of the Lower Greensand Group, the Upper Greenstone Formation and the mudstone of the Gault. The
1095:
985:
268:
sterile. On the fertile soils we see chestnut and stands of hazel and oak, while Scots Pine and Birch colonise the poorer soils.
1158:
287:
26:
870:
1280:
352:
foundation, which usually creates the right conditions for coal formation. This is found in East Kent, roughly between
1380:
1151:
1069:
1260:
1255:
950:
1320:
1315:
1205:
581:
1325:
1200:
1416:
1390:
1365:
1295:
1275:
1220:
1350:
1270:
1375:
1190:
1330:
1300:
735:
on the Isle of
Sheppey. The succession in Sheppey can be listed with modern stratigraphic terminology thus:
641:
483:
291:
1385:
1370:
1245:
1195:
1029:
922:
791:
240:. The chalk displays all its characteristic features such as steep sided dry valleys, and sunken roads.
1340:
1305:
1290:
1225:
1008:
739:
712:
591:
543:
225:
771:
1395:
1265:
620:
380:
1345:
1215:
1210:
1182:
1091:
841:. 'Clay-with-flints' is a commonly occurring deposit across the North Downs which is a product of
450:
Rocks of this age are encountered at great depth in boreholes but are not exposed at the surface.
1355:
1335:
1310:
1174:
875:
326:
152:
243:
466:
at depth. These rocks are nowhere exposed at the surface but considerable detail is known from
1360:
1240:
981:
838:
744:
647:
439:
395:
303:
299:
1250:
1235:
676:
145:
86:
498:
succession detected reflects that exposed at the surface further west in southern
England.
799:
754:
724:
716:
692:
586:
423:
407:
311:
279:
237:
194:
159:
113:
105:
90:
58:
sedimentary rocks overlain by a suite of unconsolidated deposits of more recent origin.
1012:
842:
826:
807:
732:
708:
680:
494:
Rocks of this age are encountered in boreholes but are not exposed at the surface. The
459:
435:
66:
727:. The youngest Palaeogene strata is a patch of late Eocene sand, silt and clay around
1410:
749:
704:
688:
615:
551:
523:
463:
376:
315:
283:
272:
260:
202:
121:
834:
830:
700:
664:
559:
479:
431:
411:
391:
365:
163:
78:
635:
624:
539:
535:
531:
403:
229:
141:
134:
379:. In 1776, 1950, and 28 April 2007 there were earthquakes of around 4.3. The
375:
is offshore. In 1382 and 1580 there were two earthquakes exceeding 6.0 on the
77:
is the south-easternmost county in
England. It is bounded on the north by the
1230:
858:
728:
720:
703:
above it, is a thinner band of pebbly, shelly sands and clays ascribed to the
684:
668:
357:
353:
349:
276:
264:
214:
210:
174:
125:
117:
861:
and indeed the former coastline west of
Folkestone overlooking Romney Marsh.
810:
and results in the general northward dip of the rock strata in most of Kent.
426:
lock, but in earlier times cargo-carrying vessels reached as far upstream as
302:
160–700 ft; sandstones. The
Fairlight Clays form the upper part of the
795:
787:
628:
563:
555:
527:
519:
515:
511:
475:
427:
419:
415:
399:
372:
307:
282:, and sterile soil only suited to heathland and forests of Scots Pine. The
256:
252:
233:
206:
155:
formed from Gault Clay overlaid in the north with the upper layer greensand;
137:
marshlands along the Thames/Medway estuaries and along the North Kent coast;
82:
566:. The succession can be listed with modern stratigraphic terminology thus:
1065:
854:
850:
822:
696:
507:
495:
467:
345:
295:
190:
162:, formed from the lower layer of greensand, containing the source of the
55:
51:
853:
are known along the north coast of the Isle of Sheppey, the coast near
819:
430:. The Medway has captured the head waters of other rivers such as the
70:
Geological cross section of Kent, showing how it relates to major towns
47:
22:
336:
224:
The eastern part of the Wealden dome was eroded away by the sea. The
1143:
803:
775:
672:
595:
198:
34:
371:
Seismic activity has occasionally been recorded in Kent, though the
656:
includes the 'Hastings Beds' and overlying 'Weald Clay Formation'.
846:
547:
361:
335:
322:
275:, which are resistant to weathering, leading to outcrops, such as
242:
218:
181:
170:
109:
101:
97:
93:. The continent of Europe is a mere 21 miles across the Strait.
65:
679:
is the oldest of these and occupies an area from the coast near
471:
74:
30:
1147:
1025:
825:
on the Thames Estuary coast, in the low ground surrounding the
398:
and flows some 25 miles (40 km) eastwards to a point near
340:
South-east England viewed from a NASA satellite September 2005
921:. Microsoft Encarta Online Encyclopedia 2007. Archived from
667:
overlying the Chalk are a succession of sands and clays of
50:
largely consists of a succession of northward dipping late
506:
The oldest rocks to appear at the surface in Kent are the
1133:
British Geological Survey 1:625,000 scale geological map
904:
British Geological Survey 1:625,000 scale geological map
124:. The top of the dome eventually eroded away through
786:
Kent straddles the northern limb of a regional scale
774:
occurs in a few small pockets around the village of
711:
coast is the Eocene age silty and sandy clay of the
294:
100–230 ft, shales with bands of sandstone and
1181:
402:, when it turns north. Here it breaks through the
980:Greensand Way in Kent, 1992, Kent Count Council,
1052:Wood-Names And Tree-Names On The Maps Of Britain
144:, containing the highest point of the county,
1159:
558:before turning slightly south of west at the
238:Kent Downs Area of Outstanding Natural Beauty
8:
818:There are extensive spreads of coastal and
1166:
1152:
1144:
1135:Quaternary Map of the United Kingdom South
1092:"Quake causes Kent Families to flee Homes"
833:. Alluvium also floors the valleys of the
1114:
1112:
1003:
1001:
999:
997:
995:
993:
897:
526:which underpin the wooded landscape of
976:
974:
972:
970:
806:. The fold arises from the continuing
383:caused physical damage in Folkestone.
189:feet thick, is a greyish marly chalk.
462:is a concealed coalfield working the
7:
949:. WestSussex.gov.uk. Archived from
286:are divided into three formations:
794:which extends westwards as far as
325:derives its ancient name from the
14:
1007:Britain's Structure and Scenery,
1066:"Geology of Kent and Boulonnais"
707:. North again and following the
634:Tunbridge Wells Sand Formation (
422:. The river is tidal as far as
232:meets the coast. From there to
1098:from the original on 2007-05-31
1072:from the original on 2009-11-05
1032:from the original on 2007-04-05
778:between Ashford and Maidstone.
16:Overview of the geology of Kent
288:Tunbridge Wells Sand Formation
1:
871:Geology of the United Kingdom
699:. North of this outcrop, and
470:and underground workings for
306:; grey and varigated shales.
33:. It includes the borough of
390:Kent's principal river, the
1090:Hill, Amelia (2007-04-29).
538:overlie these and form the
247:'The White Cliffs of Dover'
104:above subsequent layers of
21:This article describes the
1433:
1011:., Pub Sept 1946, Collins
550:west-northwestwards above
542:which run from the famous
85:, and on the south by the
845:during the last ice age.
770:The Miocene/Pliocene age
582:Upper Greensand Formation
1094:. London: The Guardian.
944:"Downs Link Route Guide"
906:Bedrock Geology UK South
695:and, intermittently, to
1121:Map Of The River Medway
642:Wadhurst Clay Formation
484:Carboniferous Limestone
292:Wadhurst Clay Formation
1381:West Midlands (County)
843:periglacial conditions
792:Weald-Artois Anticline
344:The Wealden dome is a
341:
248:
148:, at 251m/823 ft.
71:
740:London Clay Formation
713:London Clay Formation
592:Lower Greensand Group
490:Triassic and Jurassic
446:Silurian and Devonian
348:structure lying on a
339:
246:
226:White cliffs of Dover
69:
1068:. The Geology Shop.
1050:H. L. Edlin (1952).
798:and east across the
621:Weald Clay Formation
573:White Chalk Subgroup
536:White Chalk Subgroup
221:are built on chalk.
166:and its tributaries;
857:and either side of
576:Grey Chalk Subgroup
532:Grey Chalk Subgroup
438:, most notably the
434:. There are other
410:before joining the
180:the sandstone High
1261:Greater Manchester
1175:Geology of England
908:5th Edn. NERC 2007
876:Geology of England
342:
249:
153:Vale of Holmesdale
72:
1404:
1403:
1119:Bowskill, Derek.
1028:. KentDowns.org.
919:"English Channel"
761:Thanet Formation
745:Harwich Formation
701:stratigraphically
648:Ashdown Formation
644:(Valanginian age)
314:are built on the
304:Ashdown Formation
300:Ashdown Formation
290:130–400 ft;
27:ceremonial county
1424:
1316:Northamptonshire
1168:
1161:
1154:
1145:
1138:
1131:
1125:
1124:
1116:
1107:
1106:
1104:
1103:
1087:
1081:
1080:
1078:
1077:
1062:
1056:
1055:
1047:
1041:
1040:
1038:
1037:
1022:
1016:
1005:
988:
978:
965:
964:
962:
961:
955:
948:
940:
934:
933:
931:
930:
915:
909:
902:
847:Loessic deposits
788:upfold of strata
772:Lenham Formation
677:Thanet Formation
534:and finally the
228:occur where the
87:Straits of Dover
1432:
1431:
1427:
1426:
1425:
1423:
1422:
1421:
1417:Geology of Kent
1407:
1406:
1405:
1400:
1326:Nottinghamshire
1256:Gloucestershire
1201:Buckinghamshire
1177:
1172:
1142:
1141:
1132:
1128:
1118:
1117:
1110:
1101:
1099:
1089:
1088:
1084:
1075:
1073:
1064:
1063:
1059:
1049:
1048:
1044:
1035:
1033:
1024:
1023:
1019:
1009:L. Dudley Stamp
1006:
991:
979:
968:
959:
957:
953:
946:
942:
941:
937:
928:
926:
917:
916:
912:
903:
899:
894:
884:
882:Further reading
867:
816:
800:English Channel
784:
768:
755:Upnor Formation
725:Isle of Sheppey
715:. It underlies
662:
610:Atherfield Clay
601:Folkestone Beds
587:Gault Formation
504:
492:
456:
448:
381:2007 earthquake
312:Tunbridge Wells
280:Tunbridge Wells
160:Greensand Ridge
114:Lower Greensand
106:Upper Greensand
91:English Channel
64:
44:geology of Kent
17:
12:
11:
5:
1430:
1428:
1420:
1419:
1409:
1408:
1402:
1401:
1399:
1398:
1393:
1391:Worcestershire
1388:
1383:
1378:
1373:
1368:
1363:
1358:
1353:
1348:
1343:
1338:
1333:
1328:
1323:
1321:Northumberland
1318:
1313:
1308:
1303:
1298:
1296:Leicestershire
1293:
1288:
1283:
1278:
1273:
1268:
1263:
1258:
1253:
1248:
1243:
1238:
1233:
1228:
1223:
1218:
1213:
1208:
1206:Cambridgeshire
1203:
1198:
1193:
1187:
1185:
1179:
1178:
1173:
1171:
1170:
1163:
1156:
1148:
1140:
1139:
1126:
1108:
1082:
1057:
1042:
1017:
1013:New Naturalist
989:
966:
935:
910:
896:
895:
893:
890:
889:
888:
883:
880:
879:
878:
873:
866:
863:
827:Isle of Thanet
815:
812:
808:Alpine orogeny
802:into northern
783:
780:
767:
764:
763:
762:
759:
758:
757:
747:
742:
709:Thames Estuary
661:
658:
653:
652:
651:
650:
645:
639:
632:
613:
612:
611:
608:
605:
602:
589:
584:
579:
578:
577:
574:
503:
500:
491:
488:
474:. A number of
460:Kent Coalfield
455:
452:
447:
444:
436:rivers in Kent
186:
185:
178:
167:
156:
149:
138:
133:the low lying
63:
60:
40:
39:
15:
13:
10:
9:
6:
4:
3:
2:
1429:
1418:
1415:
1414:
1412:
1397:
1394:
1392:
1389:
1387:
1384:
1382:
1379:
1377:
1374:
1372:
1369:
1367:
1366:Tyne and Wear
1364:
1362:
1359:
1357:
1354:
1352:
1351:Staffordshire
1349:
1347:
1344:
1342:
1339:
1337:
1334:
1332:
1329:
1327:
1324:
1322:
1319:
1317:
1314:
1312:
1309:
1307:
1304:
1302:
1299:
1297:
1294:
1292:
1289:
1287:
1284:
1282:
1281:Isle of Wight
1279:
1277:
1276:Hertfordshire
1274:
1272:
1271:Herefordshire
1269:
1267:
1264:
1262:
1259:
1257:
1254:
1252:
1249:
1247:
1244:
1242:
1239:
1237:
1234:
1232:
1229:
1227:
1224:
1222:
1221:County Durham
1219:
1217:
1214:
1212:
1209:
1207:
1204:
1202:
1199:
1197:
1194:
1192:
1189:
1188:
1186:
1184:
1180:
1176:
1169:
1164:
1162:
1157:
1155:
1150:
1149:
1146:
1137:1st Edn. 1977
1136:
1130:
1127:
1122:
1115:
1113:
1109:
1097:
1093:
1086:
1083:
1071:
1067:
1061:
1058:
1053:
1046:
1043:
1031:
1027:
1021:
1018:
1014:
1010:
1004:
1002:
1000:
998:
996:
994:
990:
987:
986:1-873010-23-0
983:
977:
975:
973:
971:
967:
956:on 2007-04-22
952:
945:
939:
936:
925:on 2007-10-24
924:
920:
914:
911:
907:
901:
898:
891:
886:
885:
881:
877:
874:
872:
869:
868:
864:
862:
860:
856:
852:
848:
844:
840:
836:
832:
828:
824:
821:
813:
811:
809:
805:
801:
797:
793:
790:known as the
789:
781:
779:
777:
773:
765:
760:
756:
753:
752:
751:
750:Lambeth Group
748:
746:
743:
741:
738:
737:
736:
734:
730:
726:
722:
718:
714:
710:
706:
705:Lambeth Group
702:
698:
694:
690:
689:Sittingbourne
686:
683:east through
682:
678:
674:
670:
666:
665:Unconformably
659:
657:
649:
646:
643:
640:
637:
633:
630:
626:
622:
619:
618:
617:
616:Wealden Group
614:
609:
606:
604:Sandgate Beds
603:
600:
599:
597:
593:
590:
588:
585:
583:
580:
575:
572:
571:
569:
568:
567:
565:
561:
557:
553:
549:
545:
541:
537:
533:
529:
525:
524:Wealden Group
521:
517:
513:
509:
501:
499:
497:
489:
487:
485:
481:
480:unconformably
477:
473:
469:
465:
464:Coal Measures
461:
454:Carboniferous
453:
451:
445:
443:
442:in the east.
441:
437:
433:
429:
425:
421:
417:
414:as its final
413:
409:
405:
401:
397:
394:, rises near
393:
388:
384:
382:
378:
377:Richter Scale
374:
369:
367:
366:coal measures
363:
359:
355:
351:
347:
338:
334:
332:
328:
324:
319:
317:
316:Hastings Beds
313:
309:
305:
301:
297:
293:
289:
285:
284:Hastings Beds
281:
278:
274:
273:Hastings Beds
269:
266:
262:
258:
254:
245:
241:
239:
235:
231:
227:
222:
220:
216:
212:
208:
204:
203:Sittingbourne
200:
196:
192:
183:
179:
176:
172:
168:
165:
161:
157:
154:
150:
147:
146:Betsom's Hill
143:
139:
136:
132:
131:
130:
127:
123:
122:Hastings Beds
119:
115:
111:
107:
103:
99:
94:
92:
88:
84:
80:
76:
68:
61:
59:
57:
53:
49:
46:in southeast
45:
38:
36:
32:
28:
24:
19:
18:
1376:Warwickshire
1301:Lincolnshire
1285:
1191:Bedfordshire
1134:
1129:
1120:
1100:. Retrieved
1085:
1074:. Retrieved
1060:
1051:
1045:
1034:. Retrieved
1026:"Kent Downs"
1020:
958:. Retrieved
951:the original
938:
927:. Retrieved
923:the original
913:
905:
900:
835:River Medway
831:Romney Marsh
817:
785:
769:
663:
654:
570:Chalk Group
562:gap towards
544:White Cliffs
505:
493:
457:
449:
432:River Darent
412:River Thames
392:River Medway
389:
385:
370:
343:
330:
320:
270:
250:
223:
187:
164:River Medway
95:
79:River Thames
73:
43:
41:
20:
1371:West Sussex
1331:Oxfordshire
1246:East Sussex
829:and across
636:Valanginian
625:Hauterivian
540:North Downs
440:River Stour
404:North Downs
236:is now the
230:North Downs
142:North Downs
135:London Clay
1341:Shropshire
1306:Merseyside
1291:Lancashire
1231:Derbyshire
1102:2007-04-28
1076:2007-04-21
1036:2007-04-20
960:2007-04-20
929:2007-04-20
892:References
859:Folkestone
814:Quaternary
729:Eastchurch
721:Whitstable
685:Canterbury
669:Palaeocene
660:Palaeogene
607:Hythe Beds
520:sandstones
516:siltstones
512:limestones
502:Cretaceous
476:coal seams
396:Edenbridge
387:alluvium.
358:Canterbury
350:Palaeozoic
298:; and the
277:High Rocks
265:Folkestone
211:Canterbury
175:Weald Clay
140:the chalk
126:weathering
118:Weald Clay
1396:Yorkshire
1386:Wiltshire
1266:Hampshire
1196:Berkshire
851:Landslips
820:estuarine
796:Hampshire
782:Structure
717:Herne Bay
693:Rochester
675:age. The
629:Barremian
564:Sevenoaks
556:Maidstone
528:The Weald
508:mudstones
468:boreholes
428:Tonbridge
424:Allington
420:Sheerness
416:tributary
408:Rochester
400:Maidstone
373:epicentre
308:Tonbridge
257:Maidstone
253:Sevenoaks
234:Westerham
207:Faversham
195:Gravesend
83:North Sea
1411:Category
1346:Somerset
1216:Cornwall
1211:Cheshire
1183:Counties
1096:Archived
1070:Archived
1030:Archived
865:See also
855:Reculver
823:alluvium
723:and the
697:Dartford
681:Sandwich
496:Jurassic
346:Mesozoic
327:Germanic
296:iron ore
191:Dartford
169:the Low
120:and the
89:and the
81:and the
62:Overview
56:Cenozoic
52:Mesozoic
1356:Suffolk
1336:Rutland
1311:Norfolk
1226:Cumbria
1015:Series.
766:Neogene
733:Minster
552:Ashford
522:of the
364:. The
261:Ashford
201:Towns,
98:Wealden
48:England
25:of the
23:geology
1361:Surrey
1241:Dorset
984:
804:France
776:Lenham
673:Eocene
596:Aptian
560:Medway
360:, and
263:, and
199:Medway
197:, The
177:valley
35:Medway
1251:Essex
1236:Devon
954:(PDF)
947:(PDF)
839:Stour
598:age)
548:Dover
418:near
362:Dover
331:wald
329:word
323:Weald
219:Dover
182:Weald
171:Weald
110:Gault
102:Chalk
1286:Kent
982:ISBN
837:and
731:and
671:and
638:age)
631:age)
554:and
518:and
472:coal
458:The
354:Deal
321:The
310:and
271:The
217:and
215:Deal
173:, a
158:the
151:the
75:Kent
54:and
42:The
31:Kent
687:to
627:to
546:at
482:on
406:at
29:of
1413::
1111:^
992:^
969:^
719:,
691:,
514:,
510:,
486:.
356:,
318:.
259:,
255:,
213:,
209:,
205:,
193:,
116:,
112:,
108:,
1167:e
1160:t
1153:v
1123:.
1105:.
1079:.
1054:.
1039:.
963:.
932:.
623:(
594:(
184:.
37:.
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