359:
147:
423:
247:
325:, underlies the Torridon Group conformably, but the relationship with the Stoer Group is nowhere exposed. It is presumed to have been in deposited later that the Stoer Group, but possibly in a separate sub-basin. It is metamorphosed to greenschist facies and sits within the Kishorn Nappe, part of the Caledonian thrust belt, making its exact relationship to the other outcrops difficult to assess. The sequence consists of mainly coarse-grained
20:
341:
The
Torridon Group infills an irregular land surface with up to 600 m of topography locally, cutting down through the previously deposited Stoer group sediments, resting in many areas directly on the Lewisian. The lowest part of this group consists of a basal breccia passing up into sandstones and
470:
causing rifting and the deposition of the thick coarse clastic sequence of the
Torridonian. This was interrupted by a tilting event of unknown origin that caused a hiatus of about 200 Ma, followed by further deposition. At the start of the Cambrian, there was a marine
465:
to the
Scourian gneisses at about 3.0–2.7 Ga. Blocks within the Lewisian complex were then juxtaposed by Inverian and Laxfordian deformation from about 2.4–1.7 Ga. At about 1200 Ma, the terrane was affected by
561:
Sutton, J.; Watson J (1951). "The pre-Torridonian metamorphic history of the Loch
Torridon and Scourie areas in the north-west Highlands, and its bearing on the chronological classification of the Lewisian".
293:
is present in many areas with large clasts derived from the underlying
Lewisian. The breccia passes up into muddy sandstones, often with well-preserved desiccation structures, and into deposits of a
261:
on an old land surface, with up to 300 m of relief locally. The
Torridonian is divided into the older Stoer Group and the younger Sleat and Torridon Groups separated by an angular unconformity.
44:
189:
and deformed towards the end of the
Archaean. At the beginning of the Proterozoic, the Scourian gneisses were locally affected by deformation and retrogression to
346:
building out into ephemeral lakes. The upper parts of the group consist of an overall fining-upward sequence of sandstones, interpreted to have been deposited in a
208:, postdates the Scourian deformation and metamorphism and has therefore been used to identify the later Laxfordian event. Many of the dykes were intruded into hot
394:
390:
366:
This thin strip of Lower
Paleozoic strata lie unconformably on both the Lewisian complex and the Torridonian. The sequence is divided into the lower
309:
environment. The uppermost part of the sequence consists of trough cross-bedded sandstones thought to have been deposited by braided rivers.
265:
suggest that this unconformity represents a major time break. These sediments are interpreted to have been deposited during a period of
662:
453:, although the effects of later faulting make precise estimates of thickness difficult. It is subdivided into seven formations.
414:. The An-t-Sron Formation consists of calcareous siltstones of the Fucoid Beds and overlying sandstone of the Salterella Grit.
538:
358:
305:. A thin sequence of siltstones and fine sandstones alternate with muddy sandstones, suggesting deposition in a
228:
sheets. This deformation was accompanied by retrogression to amphibolite facies and subsequently locally to
701:
441:
The
Durness group lies conformably on the Ardvreck Group. It consists of several hundred metres of mainly
161:
gneisses, subject to a series of metamorphic and tectonic events, interrupted by the intrusion of a major
479:
the terrane became involved in the
Caledonian continental collision, with the Highland Terrane being
110:
475:
and deposition of shallow marine sandstone and carbonates continuing into the Ordovician. In the
472:
114:
398:
302:
298:
209:
526:
467:
146:
86:
229:
221:
190:
716:
193:
in the Inverian event, which overlapped in time with the emplacement of the Scourie dykes.
8:
389:
The ca. 200 m thick lower Cambrian Ardvreck Group consists of two formations, the basal
642:
620:
598:
579:
347:
257:
The Torridonian is a sequence of Neoproterozoic sediments, mainly sandstones that rest
36:
575:
706:
583:
534:
48:
97:
The Hebridean Terrane forms the westernmost strip of mainland Scotland, most of the
711:
571:
141:
63:
56:
442:
427:
182:
370:
262:
205:
102:
98:
67:
695:
677:
664:
374:
294:
120:. The full extent of this terrane to the west is obscured by the effects of
480:
411:
402:
343:
258:
397:. The Eriboll Formation contains the Basal Quartzite member, with a basal
329:
sandstones deposited in a fluvial environment with some less common grey
241:
225:
70:
422:
246:
378:
286:
162:
151:
78:
462:
446:
431:
407:
251:
186:
174:
82:
73:
sediments, which in turn are unconformably overlain by a sequence of
19:
476:
461:
The earliest event recorded in the terrane is the intrusion of the
367:
326:
202:
178:
121:
117:
106:
74:
40:
435:
290:
158:
52:
32:
643:"Sandstone with small shelly fossils, Cambrian Salterella Grit"
282:
59:
450:
330:
318:
278:
109:
and have been proved west and north of the Outer Hebrides by
599:"Quartz sandstone with vertical burrows, Cambrian Pipe Rock"
322:
306:
266:
124:
16:
Part of the Caledonian orogenic belt in northwest Scotland
181:
plutonic rocks intruded in the interval 3.0–2.7
564:
Quarterly Journal of the Geological Society of London
333:, probably deposited in a lacustrine environment.
105:. Similar rocks are also thought to be present in
524:
224:, in which the Scourie dykes occur as concordant
220:This event is associated with the development of
150:Outcrop of weathered Lewisian gneiss, 5 km NW of
693:
525:Park, R.G.; Stewart, A.D.; Wright, D.T. (2003).
560:
533:. London: Geological Society. pp. 45–61.
483:over this segment of the Laurentian foreland.
353:
277:The Stoer Group outcrops on the peninsula of
621:"Calcareous siltstone, Cambrian Fucoid Beds"
421:
357:
245:
235:
157:The Lewisian complex consists of mainly
145:
18:
520:
518:
516:
317:The Sleat Group, which outcrops on the
23:Geological map of the Hebridean Terrane
694:
640:
634:
618:
596:
590:
514:
512:
510:
508:
506:
504:
502:
500:
498:
496:
405:Pipe Rock member with its distinctive
612:
554:
362:Pipe Rock viewed on a bedding surface
177:for the Scourian complex were mainly
43:. Its boundary with the neighbouring
493:
215:
168:
135:
13:
14:
728:
576:10.1144/GSL.JGS.1950.106.01-04.16
384:
336:
81:sediments. It formed part of the
417:
342:subordinate shales deposited as
196:
66:, unconformably overlain by the
85:foreland during the Caledonian
312:
272:
1:
486:
185:. They were metamorphosed to
130:
51:. The basement is formed by
7:
430:exposed at the entrance to
354:Cambro-Ordovician sediments
10:
733:
527:"3. The Hebridean terrane"
456:
239:
139:
641:Waters, D.J. (May 2003).
619:Waters, D.J. (May 2003).
597:Waters, D.J. (May 2003).
92:
45:Northern Highland Terrane
529:. In Trewin N.H. (ed.).
401:overlain by the heavily
250:Well-bedded Torridonian
37:Caledonian orogenic belt
531:The Geology of Scotland
115:hydrocarbon exploration
438:
363:
254:
154:
113:shallow boreholes and
35:that form part of the
24:
468:extensional tectonics
425:
377:of Cambrian to lower
361:
249:
236:Torridonian sediments
201:This swarm of mainly
149:
87:continental collision
22:
702:Geology of Scotland
674: /
395:An-t-Sron Formation
299:trough cross-bedded
439:
393:and the overlying
364:
263:Paleomagnetic data
255:
230:greenschist facies
191:amphibolite facies
155:
25:
540:978-1-86239-126-0
391:Eriboll Formation
49:Moine Thrust Belt
47:is formed by the
29:Hebridean Terrane
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689:
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632:
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629:
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610:
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588:
587:
570:(1–4): 241–307.
558:
552:
551:
549:
547:
522:
373:overlain by the
216:Laxfordian event
187:granulite facies
169:Scourian complex
142:Lewisian complex
136:Lewisian complex
64:Lewisian complex
57:Paleoproterozoic
732:
731:
727:
726:
725:
723:
722:
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692:
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559:
555:
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543:
541:
523:
494:
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420:
387:
356:
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301:sandstones and
275:
244:
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218:
199:
171:
144:
138:
133:
101:and all of the
95:
17:
12:
11:
5:
730:
720:
719:
714:
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704:
678:57.66°N 6.31°W
656:
655:
633:
611:
589:
553:
539:
491:
490:
488:
485:
458:
455:
426:Durness Group
419:
416:
386:
385:Ardvreck Group
383:
371:Ardvreck Group
355:
352:
338:
337:Torridon Group
335:
314:
311:
274:
271:
240:Main article:
237:
234:
217:
214:
198:
195:
170:
167:
140:Main article:
137:
134:
132:
129:
103:Outer Hebrides
99:Inner Hebrides
94:
91:
68:Neoproterozoic
31:is one of the
15:
9:
6:
4:
3:
2:
729:
718:
715:
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473:transgression
469:
464:
454:
452:
448:
444:
437:
433:
429:
424:
418:Durness Group
415:
413:
412:trace fossils
410:
409:
404:
400:
396:
392:
382:
380:
376:
375:Durness Group
372:
369:
360:
351:
350:environment.
349:
345:
344:alluvial fans
334:
332:
328:
324:
321:peninsula on
320:
310:
308:
304:
303:conglomerates
300:
296:
295:braided river
292:
288:
284:
280:
270:
268:
264:
260:
259:unconformably
253:
248:
243:
233:
231:
227:
223:
213:
211:
207:
204:
197:Scourie dykes
194:
192:
188:
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176:
166:
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153:
148:
143:
128:
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90:
88:
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58:
54:
50:
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42:
39:in northwest
38:
34:
30:
21:
683:57.66; -6.31
659:
646:. Retrieved
636:
624:. Retrieved
614:
602:. Retrieved
592:
567:
563:
556:
544:. Retrieved
530:
460:
440:
406:
399:conglomerate
388:
365:
340:
316:
276:
256:
219:
210:country rock
200:
172:
156:
96:
28:
26:
717:Proterozoic
681: /
403:bioturbated
327:feldspathic
313:Sleat Group
273:Stoer Group
242:Torridonian
226:amphibolite
222:shear zones
71:Torridonian
696:Categories
487:References
463:protoliths
447:limestones
445:with some
379:Ordovician
307:lacustrine
289:. A basal
287:Sutherland
175:protoliths
163:dyke swarm
152:Loch Inver
131:Rock units
83:Laurentian
79:Ordovician
584:129375227
443:dolomites
432:Smoo Cave
408:skolithos
252:sandstone
707:Terranes
546:June 23,
477:Silurian
428:dolomite
368:Cambrian
297:system,
203:dolerite
179:granitic
159:granitic
122:Mesozoic
107:Shetland
60:gneisses
53:Archaean
41:Scotland
33:terranes
712:Archean
666:57°40′N
648:23 June
626:23 June
604:23 June
457:History
436:Durness
291:breccia
281:, near
267:rifting
125:rifting
77:–
62:of the
669:6°19′W
582:
537:
481:thrust
451:cherts
348:bajada
331:shales
283:Assynt
93:Extent
75:Cambro
580:S2CID
381:age.
319:Sleat
279:Stoer
206:dykes
118:wells
650:2010
628:2010
606:2010
548:2010
535:ISBN
449:and
323:Skye
173:The
55:and
27:The
572:doi
568:106
434:in
111:BGS
698::
578:.
566:.
495:^
285:,
269:.
232:.
212:.
183:Ga
165:.
127:.
89:.
652:.
630:.
608:.
586:.
574::
550:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
