Hostname: page-component-745bb68f8f-5r2nc Total loading time: 0 Render date: 2025-01-13T07:37:51.112Z Has data issue: false hasContentIssue false
  • English
  • Français

Crustal magnetization variations across the Iapetus Suture Zone

Published online by Cambridge University Press:  01 May 2009

G. S. Kimbell  and
P. Stone
G. S. Kimbell
Affiliation:
British Geological Survey, Kingsley Dunham Centre, Key worth, Nottingham NG12 5GG, UK
P. Stone
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

The Iapetus Suture (Solway) line coincides with a magnetic low, which lies between magnetic highs over southwestern Scotland and the Lake District-Isle of Man region. Although topography on deep magnetic basement can account for these long wavelength geophysical variations, an explanation which involves lateral basement magnetization contrasts is preferred on the basis of (a) correlations between inferred magnetization boundaries and major structures delineated from other evidence, and (b) the apparent westward continuation of the Solway low through Ireland and Newfoundland across areas with very different subsidence histories but similar position with respect to the collision of Laurentia and Avalonia. In the preferred model, relatively magnetic continental crust beneath the Southern Uplands and Lake District terranes is separated by a zone of less magnetic crust interpreted as sedimentary rock of Avalonian affinity carried to deeper structural levels within the Iapetus Suture Zone. The magnetic unit beneath the Southern Uplands is bounded to the south by the northward-dipping Iapetus Suture and to the north by a structure which may have been reactivated in late Caledonian times to produce the Moniaive Shear Zone in the overlying rocks; this unit may represent the ‘missing’ arc terrane inferred from provenance studies. Alternatively, the two magnetic basement domains may have originally been part of the same terrane, with that portion beneath the Southern Uplands rifting from the Avalonian continent during its northwards drift and being subsequently trapped in the hanging wall of the Iapetus Suture. The southern margin of the Lake District domain appears as a discontinuity in the magnetic anomaly pattern, with long wavelength anomalies to the south having a southeast ‘Tornquist’ trend.

Type
Articles
Information
Geological Magazine , Volume 132 , Issue 5 , September 1995 , pp. 599 - 609
Copyright
Copyright © Cambridge University Press 1995

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Al-Chalabi, M., 1970. Interpretation of two-dimensional magnetic profiles by non-linear optimisation. Bollettino di Geofisica Teorica ed Applicata 12, 3–20.Google Scholar
Anderson, T. B., & Oliver, G. J. H., 1986. The Orlock Bridge Fault: a major Late Caledonian sinistral fault in the Southern Uplands terrane, British Isles. Transactions of the Royal Society of Edinburgh 77, 203–22.CrossRefGoogle Scholar
Barnes, R. P., Phillips, E. R., & Boland, M. P., 1995. The Orlock Bridge Fault in the Southern Uplands of Scotland: a terrane boundary? Geological Magazine 132, 523–9.CrossRefGoogle Scholar
Barton, P. J., 1992. LISPB revisited: a new look under the Caledonides of northern Britain. Geophysical Journal International 110, 371–91.CrossRefGoogle Scholar
Beamish, D., 1995. Deep resistivity imaging across the Northern and Central belts of the Southern Uplands. Geological Magazine 132, 531–8.CrossRefGoogle Scholar
Beamish, D., & Smythe, D. B., 1986. Geophysical images of the deep crust: the Iapetus suture. Journal of the Geological Society, London 143, 489–97.CrossRefGoogle Scholar
Berridge, N. G., 1982. Petrography of the pre-Carboniferous rocks of the Beckermonds Scar borehole in the context of the magnetic anomaly at the site. Proceedings of the Yorkshire Geological Society 44, 89–98.CrossRefGoogle Scholar
Blundell, D. J., Hobbs, R. W., Klemperer, S. L., Scottrobinson, R., Long, R. E., West, T. E., & Duin, E., 1991. Crustal structure of the central and southern North Sea from BIRPS deep seismic reflection profiling. Journal of the Geological Society, London 148, 445–57.CrossRefGoogle Scholar
Bott, M. H. P., 1965. The deep structure of the northern Irish Sea — a problem of crustal dynamics. In Submarine geology and geophysics (eds Whittard, W. F. and Bradshaw, R.), pp. 179–204. Colston Paper no. 17.Google Scholar
Bott, M. H. P., 1967. Geophysical investigations of northern Pennine basement rocks. Proceedings of the Yorkshire Geological Society 36, 139–68.CrossRefGoogle Scholar
Bott, M. H. P., & Masson, Smith D., 1957. Interpretation of a vertical field magnetic survey in north-east England. Quarterly Journal of the Geological Society, London 113, 119–36.CrossRefGoogle Scholar
Brewer, J. A., Matthews, D. H., Warner, M. R., Hall, J., Smythe, D. K., & Whittington, R. J., 1983. BIRPS deep seismic reflection studies of the British Caledonides — the WINCH profile. Nature 305, 206–10.CrossRefGoogle Scholar
Chadwick, R. A., Evans, D. J., & Holliday, D. W., 1993. The Maryport fault: the post-Caledonian tectonic history of southern Britain in microcosm. Journal of the Geological Society, London 150, 247–50.CrossRefGoogle Scholar
Chadwick, R. A., & Holliday, D. W., 1991. Deep crustal structure and Carboniferous basin development within the Iapetus convergence zone, northern England. Journal of the Geological Society, London 148, 41–53.CrossRefGoogle Scholar
Chapman, D. S., 1986. Thermal gradients in the continental crust. In The Nature of the Lower Continental Crust (eds Dawson, J. B., Carswell, D. A., Hall, J. and Wedepohl, K. H.), pp. 63–70. Geological Society Special Publication no. 24.Google Scholar
Cocks, L. R. M., & Fortey, R. A., 1982. Faunal evidence for oceanic separations in the Palaeozoic of Britain. Journal of the Geological Society, London 139, 465–78.CrossRefGoogle Scholar
Colman-Sadd, S. P., & Swinden, H. S., 1984. A tectonic window in Central Newfoundland? Geological evidence that the Appalachian Dunnage Zone may be allochthonous. Canadian Journal of Earth Science 21, 1349–67.CrossRefGoogle Scholar
Cooper, A. H., Millward, D., Johnson, E. W., & Soper, N. J., 1993. The early Palaeozoic evolution of northwest England. Geological Magazine 130, 711–24.CrossRefGoogle Scholar
Cordell, L. E., & Grauch, V. J. S., 1985. Mapping basement magnetization zones from aeromagnetic data in the San Juan basin, New Mexico. In The utility of regional gravity and magnetic anomaly maps (ed. Hinzman, W. J.), pp. 181–97. Tulsa: Society of Exploration Geophysicists.CrossRefGoogle Scholar
Dawson, J., Floyd, J. D., Philip, P. R., Burley, A. J., Allsop, J. M., & Bennett, J. R. P., 1977. A mineral reconnaissance survey of the Doon-Glenkens area, south-west Scotland. Mineral Reconnaissance Programme Report, Institute of Geological Sciences, no. 18.Google Scholar
Evans, A. D., 1993. Analysis of the geomagnetic total-field secular variation in Europe since 1945. Part 1 — Data tables. Project Note, Regional Geophysics Group, British Geological Survey, no. 93/2.Google Scholar
Floyd, J. D., 1994. The derivation and definition of the ‘Southern Upland Fault’: a review of the Midland Valley—Southern Uplands terrane boundary. Scottish Journal of Geology 30, 51–62.CrossRefGoogle Scholar
Floyd, J. D., & Kimbell, G. S., 1995. Magnetic and tectonostratigraphic correlation at a terrane boundary: the Tappins Group of the Southern Uplands. Geological Magazine 132, 515–21.CrossRefGoogle Scholar
Freeman, B., Klemperer, S. L., & Hobbs, R. W., 1988. The deep structure of northern England and the Iapetus Suture zone from BIRPS deep seismic reflection profiles. Journal of the Geological Society, London 145, 727–40.CrossRefGoogle Scholar
Frost, B. R., & Shive, P. N., 1986. Magnetic mineralogy of the lower continental crust. Journal of Geophysical Research 91, 6513–21.CrossRefGoogle Scholar
Gardiner, C. I., & Reynolds, S. H., 1932. The Loch Doon ‘Granite’ area, Galloway. Quarterly Journal of the Geological Society of London 88, 1–33.CrossRefGoogle Scholar
Gebski, J. S., Wheildon, J., & Thomas-Betts, A., 1987. Investigations of the UK heat flow field (1984–1987). Investigation of the Geothermal Potential of the UK. Keyworth: British Geological Survey.Google Scholar
Hall, J., Brewer, J. A., Matthews, D. H., & Warner, M. R., 1984. Crustal structure across the Caledonides from the ‘WINCH’ seismic reflection profile: influences on the evolution of the Midland Valley of Scotland. Transactions of the Royal Society of Edinburgh 75, 97–109.CrossRefGoogle Scholar
Hall, J., Powell, D. W., Warner, M. R., El-Isa, Z. H. M., Adesanya, O., & Bluck, B. J., 1983. Seismological evidence for shallow crystalline basement in the Southern Uplands of Scotland. Nature 305, 418–20.CrossRefGoogle Scholar
Hughes, R. A., Cooper, A. H., & Stone, P., 1993. Structural evolution of the Skiddaw Group (English Lake District) on the northern margin of eastern Avalonia. Geological Magazine 130, 621–9.CrossRefGoogle Scholar
Jacobi, R. D., & Kristoffersen, Y., 1981. Transatlantic correlations of geophysical anomalies on Newfoundland, British Isles, France and adjacent continental shelves. In Geology of the North Atlantic Borderlands, pp. 197–229. Canadian Society of Petroleum Geologists, Memoir no. 7.Google Scholar
Jackson, D. I., & Mulholland, P., 1993. Tectonic and stratigraphic aspects of the East Irish Sea Basin and adjacent areas: contrasts in their post-Carboniferous structural styles. In Petroleum Geology of Northwest Europe: Proceedings of the 4th Conference (ed. Parker, J. R.), pp. 791–808. London: The Geological Society.Google Scholar
Kimbell, G. S., 1991. An assessment of geophysical data from the Rhins of Galloway district, south-west Scotland. British Geological Survey Technical Report WK/91/10.Google Scholar
Klemperer, S. L., 1989. Seismic reflection evidence for the location of the Iapetus suture west of Ireland. Journal of the Geological Society, London 146, 409–12.CrossRefGoogle Scholar
Klemperer, S. L., & Hobbs, R. H., 1991. The BIRPS Atlas. Cambridge, UK: Cambridge University Press.Google Scholar
Klemperer, S. L., & Matthews, D. H., 1987. Iapetus Suture located beneath the North Sea by BIRPS deep seismic reflection profiling. Geology 15, 195–8.2.0.CO;2>CrossRefGoogle Scholar
Klemperer, S. L., Ryan, P. D., & Snyder, D. B., 1991. A deep seismic reflection transect across the Irish Caledonides. Journal of the Geological Society, London 148, 149–64.CrossRefGoogle Scholar
Kneller, B. C., & Bell, A. M., 1993. An Acadian mountain front in the English Lake District: the Westmorland Monocline. Geological Magazine 130, 203–13.CrossRefGoogle Scholar
Kneller, B. C., King, L. M., & Bell, A. M., 1993. Foreland basin development and tectonics on the northwest margin of eastern Avalonia. Geological Magazine 130, 691–7.CrossRefGoogle Scholar
Lagios, E., & Hipkin, R. G., 1979. The Tweeddale Granite — a newly discovered batholith in the Southern Uplands. Nature 280, 672–5.CrossRefGoogle Scholar
Lagios, E., & Hipkin, R. G., 1982. A geophysical approach to the granite batholith under the eastern Southern Uplands, Scotland.Pageoph 120, 375–88.CrossRefGoogle Scholar
Lee, M. K., 1989. Upper crustal structure of the Lake District from modelling and image processing of potential field data. British Geological Survey Technical Report WK/89/1.Google Scholar
Lee, M. K., Pharaoh, T. C., & Soper, N. J., 1990. Structural trends in central Britain from images of gravity and aeromagnetic fields. Journal of the Geological Society, London 147, 241–58.CrossRefGoogle Scholar
Lintern, B. C., Barnes, R. P., & Stone, P., 1992. Discussion on Silurian and early Devonian deformation of the Ratagain Granite, Scotland: constraints on the age of Caledonian movements on the Great Glen system. Journal of the Geological Society, London 149, 858.Google Scholar
Livelybrooks, D., Banks, R. J., Parr, R. S., & Hutton, V. R. S., 1993. Inversion of electromagnetic induction data for the Iapetus Suture Zone in the UK. Physics of the Earth and Planetary Interiors 81, 67–84.CrossRefGoogle Scholar
Max, M. D., & Inamdar, D. D., 1985. Magnetic and generalised geological compilation map of Ireland (1:1, 000, 000). Dublin: Geological Survey of Ireland.Google Scholar
McKerrow, W. S., & Soper, N. J., 1989. The Iapetus suture in the British Isles. Geological Magazine 126, 1–8.CrossRefGoogle Scholar
Meissner, R., Matthews, D., & Wever, Th., 1986. The ‘Moho’ in and around Great Britain. Annales Geophysicae 4, 659–64.Google Scholar
Parr, R. S., & Hutton, V. R. S., 1993. Magnetotelluric studies in and adjacent to the Northumberland Basin, northern England. Physics of the Earth and Planetary Interiors 81, 43–66.CrossRefGoogle Scholar
Parslow, G. R., & Randall, B. A., 1973. A gravity survey of the Cairnsmore of Fleet granite and its environs. Scottish Journal of Geology 9, 219–31.CrossRefGoogle Scholar
Pharaoh, T. C., Merriman, R. J., Webb, P. C., & Beckinsale, R. D., 1987. The concealed Caledonides of eastern England: preliminary results of a multidisciplinary study. Proceedings of the Yorkshire Geological Society 46, 355–69.CrossRefGoogle Scholar
Phillips, A. E., Stillman, C. J., & Murphy, T., 1976. A Caledonian plate tectonic model. Quarterly Journal of the Geological Society of London 132, 579–609.CrossRefGoogle Scholar
Pidgeon, R. T., & Aftalion, M., 1978. Cogenetic and inherited zircon U-Pb systems in granites: Palaeozoic granites of Scotland and England. Crustal evolution in northwestern Britain and adjacent regions (eds Bowes, D. R. and Leake, B. E.), pp. 183–220. Geological Journal Special Issue no. 10.Google Scholar
Powell, D. W., 1970. Magnetised rocks within the Lewisian of Western Scotland and under the Southern Uplands. Scottish Journal of Geology 6, 353–69.CrossRefGoogle Scholar
Powell, D. W., 1971. A model for the Lower Palaeozoic evolution of the southern margin of the early Caledonides of Scotland and Ireland. Scottish Journal of Geology 7, 369–72.CrossRefGoogle Scholar
Smith, I. F., & Royles, C. P., 1989. The digital aeromagnetic survey of the United Kingdom. British Geological Survey Technical Report WK/89/5.Google Scholar
Soper, N. J., England, R. W., Snyder, D. B., & Ryan, P. D., 1992. The Iapetus suture zone in England, Scotland and eastern Ireland: a reconciliation of geological and deep seismic data. Journal of the Geological Society, London 149, 697–700.CrossRefGoogle Scholar
Soper, N. J., Webb, B. C., & Woodcock, N. H., 1987. Late Caledonian (Acadian) transpression in north-west England: timing, geometry and geotectonic significance. Proceedings of the Yorkshire Geological Society 46, 175–92.CrossRefGoogle Scholar
Stone, P., Floyd, J. D., Barnes, R. P., & Lintern, B. C., 1987. A sequential back-arc and foreland basin thrust duplex model for the Southern Uplands of Scotland. Journal of the Geological Society, London 144, 753–64.CrossRefGoogle Scholar
Stone, P., Green, P. M., Lintern, B. C., Simpson, P. R., & Plant, J. A., 1993. Regional geochemical variation across the Iapetus Suture Zone: tectonic implications. Scottish Journal of Geology 29, 113–21.CrossRefGoogle Scholar
Van der Pluijm, B. A., & Van Staal, C. R., 1988. Characteristics and evolution of the Central Mobile Belt, Canadian Appalachians. Journal of Geology 96, 535–47.CrossRefGoogle Scholar
Wasilewski, P. J., & Mayhew, M. A., 1992. The Moho as a magnetic boundary revisited. Geophysical Research Letters 19, 2259–62.CrossRefGoogle Scholar
Webb, B. C., & Cooper, A. H., 1988. Slump folds and gravity slide structures in a Lower Palaeozoic marginal basin sequence (the Skiddaw Group), NW England. Journal of Structural Geology 10, 463–72.CrossRefGoogle Scholar