The significance of a reliable Ordovician age for some Highland Border rocks in Central Scotland

Curry, Gordon B.; Ingham, J. K.; Bluck, B. J.; Williams, Alwyn

doi:10.1144/gsjgs.139.4.0451

Cited by 60 publications

(56 citation statements)

References 15 publications

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“…2), separated by unconformities are recognized in the Highland Border Complex (Curry et al 1982Bluck et al 1984). The oldest (1) consists of serpentinites and associated lithologies, originally largely harzburgitic, interpreted as an ophiolite (Henderson & Robertson, 1982) at least partly older than c. 540 Ma (the cooling age of the Bute amphibolite (Dempster & Bluck, 1991)).…”

Section: A3 the Highland Border Complexmentioning

confidence: 99%

The Antrim–Galway Line: a resolution of the Highland Border Fault enigma of the Caledonides of Britain and Ireland

Ryan

Soper

Snyder³

et al. 1995

Geol. Mag.

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The westward continuation of the Highland Border fault of Scotland (HBFZ) into Ireland is problematic. It is widely thought to follow a pronounced magnetic and gravity lineament, the Fair Head-Clew Bay Line (FCL). The advantage of this interpretation is that it places all the Ordovician ophiolitic complexes and associated sedimentary basins to the south of the FCL, which would represent the contact between Laurentia and the outboard terranes. Its main shortcomings are that both the deep structure and timing of strike-slip are different on the HBFZ and FCL. In Ireland the FCL is a north-dipping feature that can be traced to the Moho on BIRPS profiles, while the HBFZ has no such signature. Terrane amalgamation in western Ireland was completed by the late Ordovician, while in Scotland the Midland Valley terrane did not finally dock until the early Devonian. These considerations suggest that in western Ireland a branch of the HBFZ exists, which was active in post-Ordovician time and must lie south of Connemara.

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Section: A3 the Highland Border Complexmentioning

confidence: 99%

The Antrim–Galway Line: a resolution of the Highland Border Fault enigma of the Caledonides of Britain and Ireland

Ryan

Soper

Snyder³

et al. 1995

Geol. Mag.

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“…A considerable amount of new critical informtion has emerged in recent years on the rocks of the Highland Border Complex (Curry et al 1982Bluck, 1986;Bluck et al 1984). The stratigraphic sequence now established shows evidence of a pre-Arenig ophiolite overlain unconformably by a shallow water Arenig limestone.…”

Section: CL Highland Border Terranementioning

confidence: 99%

Strike-slip terranes and a model for the evolution of the British and Irish Caledonides

Hutton

1987

Geol. Mag.

178

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“…This might also have been the case for the deposits of the NW Highlands, so that the continental shelf would have originally spread eastwards by some considerable distance (Bluck et al 1997;Bluck 2007;and Figs 2b, 3). The age of this continental margin sequence overlaps with the ages of the Highland Border Complex which are ±490-470 Ma (Curry et al 1982;Chew et al 2010) and younger. It is likely that this complex, if it was obducted from the south, was transported on to this passive margin sequence.…”

Section: Laurentian Marginmentioning

confidence: 65%

Geotectonic evolution of Midland Scotland from Cambrian to Silurian: a review

Bluck

2013

SJG

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Synopsis During its Lower Palaeozoic history, the Midland Valley of Scotland was subject to compression from the blocks on either side, confirming the views of Kennedy (1958). Cambrian–Llanvirn-aged rocks of the Hebridean craton formed part of a passive margin, which extended to the ESE and is now replaced by the metamorphic complexes of the Moine and Dalradian. Both blocks had undergone metamorphism, uplift and shedding of their covers elsewhere. The ophiolitic part of the Highland Border Complex, which may be a continuation of the structurally foreshortened and rotated Ballantrae Complex, was obducted at c .490 Ma and may have interacted with rocks of the Hebridean passive margin. Ordovician rocks at Girvan are a small remnant of a one-time far larger forearc basin, which formed to the south of a major arc complex, originally situated in the Midland Valley and probably extending from somewhere in the North Sea to offshore Ireland and beyond. The Highland Border Complex includes rocks coeval with the Midland Valley arc at c .470 Ma that formed a back-arc basin. The Southern Uplands have converged on the Midland Valley, with the forearc sequence apparently missing in Scotland. Part of that convergence history is recorded in the Silurian conglomerates of the southern Midland Valley. Silurian sequences in this area contain conglomerates and breccias, derived from the south that record the presence of an igneous and possibly also a metamorphic complex in the region now occupied by the trench sequence of the Southern Uplands. It is suggested that the trench was later thrust over this source block and that the Southern Upland Fault forms part of that thrust sequence. The metamorphic complexes to the north, replacing the Hebridean passive margin, did not interact with the Midland Valley until Lower Devonian times. It follows that there was no mountain-building orogeny in Scotland, other than an arc, a sliver of trench, and numerous examples of crustal contraction by strike-slip and/or thrusting.

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The significance of a reliable Ordovician age for some Highland Border rocks in Central Scotland

Abstract: A Lower Arenig fauna with North American affinities has been rediscovered at Dounans, Aberfoyle, Central Scotland. This discovery makes part of the Highland Border Complex younger than the adjacent Dalradian rocks, and suggests a provenance from the S.

Cited by 60 publications

References 15 publications

The Antrim–Galway Line: a resolution of the Highland Border Fault enigma of the Caledonides of Britain and Ireland

The Antrim–Galway Line: a resolution of the Highland Border Fault enigma of the Caledonides of Britain and Ireland

Strike-slip terranes and a model for the evolution of the British and Irish Caledonides

Geotectonic evolution of Midland Scotland from Cambrian to Silurian: a review

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