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Discussion of Searle, ‘Tectonic evolution of the Caledonian orogeny in Scotland: a review based on the timing of magmatism, metamorphism and deformation’

Published online by Cambridge University Press:  05 September 2022

John F. Dewey Open the ORCID record for John F. Dewey [Opens in a new window]  and
Paul D. Ryan Open the ORCID record for Paul D. Ryan [Opens in a new window]
John F. Dewey*
Affiliation:
University College, High Street, OxfordOX1 4BH, UK
Paul D. Ryan
Affiliation:
School of Natural Sciences, Earth and Ocean Sciences, National University of Ireland Galway, University Road, Galway, Ireland
*
Author for correspondence: John F. Dewey, Email: jfdeweyrocks@gmail.com
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Abstract

Searle (2022) argues, based on data from Scotland alone, that the deformation and metamorphism of the Scottish Highlands is continuously diachronous from the early Ordovician (Grampian) in the Dalradian of the Grampian Highlands to the mid-Silurian (Scandian) in the Moine of the Northwest Highlands. Necessarily, he disputes substantial offset along the Great Glen Fault (GGF). He compares the Scottish Caledonides with the Himalayas. We take the different view, which also considers evidence from along-strike in Ireland and Newfoundland, that the Grampian and Scandian orogenies were discrete events. The Grampian Orogeny involved major deformation and metamorphism across the Grampian and Northwest Highlands to the Moine Thrust Zone, whereas the Scandian Orogeny affected only the Northwest Highlands. The early Ordovician Grampian Orogeny was generated by the collision and obduction of an oceanic arc-ophiolite with and onto the Laurentian continent. The mid-Silurian Scandian Orogeny was caused by continental collision between Laurentia and Baltica. Late Silurian – early Devonian sinistral slip along the GGF emplaced the the Moine of the Northwest Highlands from a distant location to the north in the Scandian collision zone, against the Dalradian, which had not been involved in the Scandian collision. We outline several (eight) arguments that we believe contradict evidence for progressive northwestward propagation of a Himalaya-style thrust wedge from the early Ordovician to the mid-Silurian.

Keywords

GrampianScandianOrogeny
Type
Discussion
Information
Geological Magazine , Volume 159 , Issue 10 , October 2022 , pp. 1833 - 1836
Copyright
© The Author(s), 2022. Published by Cambridge University Press

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References

Anderson, TB (2000) Structural interpretations of the Southern Uplands Terrane. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, 363–73.CrossRefGoogle Scholar
Archibald, DB, Lauren, MG, Macquarrie, J, Murphy, B, Strachan, RA, McFarlane, CRM, Button, M, Larson, KP and Dunlop, J (2021) The construction of the Donegal Composite Batholith, Irish Caledonides: temporal constraints from U-Pb dating of zircon and titanite. Bulletin of the Geological Society of America 133, 2335–54.Google Scholar
Archibald, DB, Murphy, JB, Fowler, M, Strachan, RA and Hidebrand, RS (2022) Testing petrogenetic models for contemporaneous mafic and felsic to intermediate magmatism within the “Newer Granite” suite of the Scottish and Irish Caledonides. Geological Society of America Special Paper 554, 1–25.Google Scholar
Atherton, MP and Ghani, AA (2002) Slab break-off: a model for Caledonian, Late Granite syn-collisional magmatism in the Orthotectonic (Metamorphic) Zone of Scotland and Donegal, Ireland. Lithos 62, 65–85.CrossRefGoogle Scholar
Batchelor, R, Harper, DAT and Anderson, TB (2003) Geochemistry and potential correlation of Silurian (Telychian) metabentonites from Ireland and SW Scotland. Geological Journal 38, 161–74.CrossRefGoogle Scholar
Cameron, IB and Stephenson, D (1985) British Regional Geology: The Midland Valley of Scotland, 3rd edn. Reprint 2014. Keyworth, Nottingham: British Geological Survey.Google Scholar
Chew, DM and Stillman, CJ (2009) Late Caledonian orogeny and magmatism. In The Geology of Ireland, 2nd edn. pp. 143–73. Edinburgh: Dunedin Academic Press.Google Scholar
Chew, DM and Strachan, RA (2014) The Laurentian Caledonides of Scotland and Ireland. In New Perspectives on the Caledonides of Scandinavia and Related Areas (eds Chew, DM, Gasser, D and Corfu, F), pp. 45–91. Geological Society of London, Special Publication no. 390.Google Scholar
Cooper, M, Crowley, Q and Rushton, A (2008) New age constraints for the Ordovician Tyrone Volcanic Group, Northern Ireland. Journal of the Geological Society 165, 333–9.CrossRefGoogle Scholar
Dewey, JF (2005) Orogeny can be very short. Proceedings of the National Academy of Sciences 102, 15286–93.CrossRefGoogle ScholarPubMed
Dewey, JF and Casey, JF (2021) Mid-Ordovician subduction, obduction, and eduction in western Newfoundland: an eclogite problem. South African Geological Journal 124, 1–10.Google Scholar
Dewey, JF, Dalziel, IWD, Reavy, J and Strachan, RA (2012) The Neo-Proterozoic to mid-Devonian evolution of Scotland: a review and some unresolved issues. Scottish Journal of Geology 51, 5–30.CrossRefGoogle Scholar
Dewey, JF and Strachan, RA (2003) Changing Silurian-Devonian relative plate motion in the Caledonides: sinistral transpression to sinistral transtension. Journal of the Geological Society of London 160, 219–29.CrossRefGoogle Scholar
Floyd, JD (2000) The Southern Uplands terrane: a stratigraphical review. Earth and Environmental Science Transactions of the Royal Society of Edinburgh 91, 349–62.CrossRefGoogle Scholar
Graham, JR (2021) Geology of South Mayo: A Field Guide. Dublin: Geological Survey of Ireland, 158pp.Google Scholar
Herrington, RJ, Hollis, SP, Cooper, MR, Stobbs, I, Tapster, S, Rushton, A, McConnell, B and Jeffries, T (2018) Age and geochemistry of the Charlestown Group, Ireland: implications for the Grampian orogeny, its mineral potential and the Ordovician timescale. Lithos 302, 1–19.CrossRefGoogle Scholar
Kennedy, WQ (1946) The Great Glen Fault. Quarterly Journal of the Geological Society 102, 41–76.CrossRefGoogle Scholar
Kirkland, CL, Alsop, GI, Daly, JS, Whitehouse, MJ, Lam, R and Clark, C (2013) Constraints on the timing of Scandian deformation and the nature of a buried Grampian terrane under the Caledonides of northwestern Ireland. Journal of the Geological Society 170, 615–25.CrossRefGoogle Scholar
Klemperer, SL (1989) Seismic reflection evidence for the location of the Iapetus suture west of Ireland. Journal of the Geological Society of London 146, 409–12.CrossRefGoogle Scholar
Lambert, RSJ, Holland, J and Leggett, J (1981) Petrology and tectonic setting of some Ordovician volcanic rocks from the Southern Uplands of Scotland. Journal of the Geological Society 138, 421–36.CrossRefGoogle Scholar
Miles, A, Woodcock, N and Hawkesworth, C (2016) Tectonic controls on post-subduction granite genesis and emplacement: the late Caledonian suite of Britain and Ireland. Gondwana Research 39, 250–60.CrossRefGoogle Scholar
Mohr, PA (1998) Late-Caledonian syn-tectonic magmatism in North-West Connemara: the Binn Chuanna Sill. Irish Journal of Earth Sciences 16, 1–18.Google Scholar
Murphy, JB, Nance, DR, Gabler, LB, Martell, A and Archibald, DA (2019) Age, geochemistry and origin of the Ardara appinite plutons, northwest Donegal, Ireland. Geoscience Canada 46, 31–48.CrossRefGoogle Scholar
Oliver, GJH, Wilde, SA and Wan, Y (2008) Geochronology and geodynamics of Scottish granitoids from the late Neoproterozoic break-up of Rodinia to Palaeozoic collision. Journal of the Geological Society 165, 661–74.CrossRefGoogle Scholar
Parkes, MA (1993) Silurian (Telychian) fossil assemblages from the Charlestown Inlier, County Mayo. Irish Journal of Earth Sciences 12, 27–40.Google Scholar
Paterson, B, Rogers, G, Stephens, WE and Hinton, RW (1993) The longevity of acid-basic magmatism associated with a major transcurrent fault. Geological Society of America , Abstracts with Programs 25, A42.Google Scholar
Rogers, G and Dunning, GR (1991) Geochronology of appinitic and related granitic magmatism in the W Highlands of Scotland: constraints on the timing of transcurrent fault movement. Journal of the Geological Society 148, 17–27.CrossRefGoogle Scholar
Ryan, PD and Dewey, JF (2004) The South Connemara Group reinterpreted: a subduction-accretion complex in the Caledonides of Galway Bay, western Ireland. Journal of Geodynamics 37, 13–529. doi: 10.1016/j.jog.2004.02.018.CrossRefGoogle Scholar
Ryan, PD and Dewey, JF (2011) Arc–continent collision in the Ordovician of western Ireland: stratigraphic, structural and metamorphic evolution. In Arc-Continent Collision (eds Brown, D and Ryan, PD), pp. 373–401. Berlin: Springer.CrossRefGoogle Scholar
Searle, MP (2022) Tectonic evolution of the Caledonian orogeny in Scotland: a review based on the timing of magmatism, metamorphism and deformation. Geological Magazine 159, 125–52. doi: 10.1017/S0016756821000947.CrossRefGoogle Scholar
Simon, JB (1986) Provenance and setting of some Ordovician and Silurian conglomerates in Northern Ireland. Scottish Journal of Geology 22, 63–76. doi: 10.1144/sjg22010063.CrossRefGoogle Scholar
Soper, NJ, England, R, Snyder, D and Ryan, PD (1992) The Iapetus suture zone in England, Scotland and eastern Ireland: a reconciliation of geological and deep seismic data. Journal of the Geological Society of London 149, 697–700.CrossRefGoogle Scholar
Stewart, E, Baxter, EF and Ague, JJ (2017) Initiation and duration of Grampian orogenesis constrained by refined Sm–Nd garnet geochronology of the Ballantrae ophiolite, Scotland. Journal of the Geological Society 174, 968–78.CrossRefGoogle Scholar
Stone, P, McMillan, AA, Floyd, JD, Barnes, RP and Phillips, ER (2012) British Regional Geology: South of Scotland, 4th edn. Keyworth, Nottingham: British Geological Survey.Google Scholar
Waldron, JWF, Floyd, JD, Simonetti, A and Heaman, LM (2008) Ancient Laurentian detrital zircon in the closing Iapetus Ocean, Southern Uplands Terrane, Scotland. Geology 36, 527–30. doi: 10.1130/G24763A.1.CrossRefGoogle Scholar
Williams, DM and Harper, DAT (1988) A basin model for the Silurian of the Midland Valley of Scotland and Ireland. Journal of the Geological Society 145, 741–8.CrossRefGoogle Scholar
Williams, DM, O’Connor, PD and Menuge, JF (1992) Silurian turbidite provenance and the closure of Iapetus. Journal of the Geological Society 149, 349–57.CrossRefGoogle Scholar
Winchester, JA (1973) Patterns of regional metamorphism suggest sinistral displacement of 160 km along the Great Glen Fault. Nature 246, 81–4.Google Scholar
Zagorevski, A and McNicoll, V (2011) Evidence for seamount accretion to a peri-Laurentian arc during closure of Iapetus. Canadian Journal of Earth Science 49, 147–65.CrossRefGoogle Scholar