Keywords
zircon
provenance
Triassic
Devon
How to Cite
Abstract
An integrated heavy-mineral, mineral-chemical and zircon-dating study of the Triassic succession exposed on the south Devon coast, in the western part of the Wessex Basin, indicates derivation from a combination of granitic and metasedimentary lithologies of ages of mostly over 550 Ma. These sources were probably located at a relatively proximal location near the southern margin of the basin. Derivation from more distal sources in the Armorican Massif or local Variscan sources to the west appears unlikely in view of the scarcity of Permo-Carboniferous (Variscan-age) zircons. The Budleigh Salterton Pebble Bed Formation was derived from a different combination of source lithologies than the Otter Sandstone Formation, the former including staurolite-grade metasediments that were absent in the catchment area of the Otter Sandstone. The Devon coast succession has provenance characteristics that differ from equivalent sandstones further east in the Wessex Basin, and from sandstones in the East Irish Sea Basin to the north. These differences indicate that sediment supply patterns to the linked Triassic basin systems in southern Britain are complex, involving multiple distinct sub-catchment areas, and that heavy-mineral studies have considerable potential for unravelling these sub-catchment area sources.
References
Audley-Charles, M.G., 1970. Triassic palaeogeography of the British Isles. Quarterly Journal of the Geological Societyof London 126, 49-89. DOI: https://www.doi.org/10.1144/gsjgs.126.1.0049
Ballèvre, M., Bosse, V., Ducassou, C. & Pitra, P., 2009. Palaeozoic history of the Armorican Massif: models for the tectonic evolution of the suture zones. Comptes Rendus de Géoscience 341, 174-201. DOI: https://www.doi.org/10.1016/j.crte.2008.11.009
Brown, M. & Dallmeyer, R.D., 1996. Rapid Variscan exhumation and the role of magma in core complex formation: southern Brittany metamorphic belt, France. Journal of Metamorphic Geology 14, 361-379. DOI: https://www.doi.org/10.1111/j.1525-1314.1996.00361.x
Brun, J.P., Guennoc, P., Truffert, C., Vairon, J. & The ARMOR Working Group of the GeoFrance 3-D Program, 2001. Cadomian tectonics in northern Brittany: a contribution of 3-D crustal-scale modelling. Tectonophysics 331, 229-246. DOI: https://www.doi.org/10.1016/S0040-1951(00)00244-4
Butler, M., 1998. The geological history and the southern Wessex Basin - a review of new information from oil exploration. [In:] J.R. Underhill (Ed.): Development, evolution and petroleum geology of the Wessex Basin. Geological Society of London, Special Publication 133, 67-86. DOI: https://www.doi.org/10.1144/GSL.SP.1998.133.01.04
Calvez, J.Y. & Vidal, P., 1978. Two billion year old relicts in the Hercynian Belt of western Europe. Contributions to Mineralogy and Petrology 65, 395-399. DOI: https://www.doi.org/10.1007/BF00372286
Campbell-Smith, W., 1963. Description of the igneous rocks represented among pebbles from the Bunter Pebble Beds of the Midlands of England. Bulletin of the British Museum of Natural History (Mineralogy) 2, 1-17.
Catalán, J.R.M., Fernández-Suárez, J., Jenner, G.A., Belousova, E. & Montez, A.D., 2004. Provenance constraints from detrital zircon U-Pb ages in the NW Iberian Massif: implications for Palaeozoic plate configuration and Variscan evolution. Journal of the Geological Society 161, 463-476. DOI: https://www.doi.org/10.1144/0016-764903-054
Cocks, L.R.M., 1993. Triassic pebbles, derived fossils and the Ordovician to Devonian palaeogeography of Europe. Journal of the Geological Society 150, 219-226. DOI: https://www.doi.org/10.1144/gsjgs.150.2.0219
Dinis, P., Andersen, T., Machado, G. & Guimarães, F., 2012. Detrital zircon U-Pb ages of a late-Variscan Carboniferous succession associated with the Porto- Tomar shear zone (West Portugal): provenance implications. Sedimentary Geology 273/274, 19-29. DOI: https://www.doi.org/10.1016/j.sedgeo.2012.06.007
Edmonds, E.A. & Williams, B.J., 1985. Geology of the countryaround Taunton and the Quantock Hills - Memoir for1:50,000 geological sheet 295 (England and Wales). British Geological Survey, HMSO, London.
Edwards, R.A., 1999. The Minehead district: a concise accountof the geology - Memoir for 1:50,000 geological sheet278 and part of sheet 294 (England and Wales). British Geological Survey, HMSO, London.
Edwards, R.A., Warrington, G., Scrivener, R.C., Jones, N.S., Haslam, H.W. & Ault, L., 1997. The Exeter Group, south Devon, England: a contribution to the early post-Variscan stratigraphy of northwest Europe. Geological Magazine 134, 177-197. DOI: https://www.doi.org/10.1017/S001675689700664X
Fitch, F.J., Miller, J.A. & Thompson, D.B., 1966. The palaeogeographic significance of isotopic age determinations on detrital micas from the Triassic of the Stockport-Macclesfield district, Cheshire, England. Palaeogeography, Palaeoclimatology, Palaeoecology 2, 281-312. DOI: https://www.doi.org/10.1016/0031-0182(66)90021-6
Frei, D. & Gerdes, A., 2009. Precise and accurate in-situ U-Pb dating of zircon with high sample throughput by automated LA-SF-ICP-MS. Chemical Geology 261, 261-270. DOI: https://www.doi.org/10.1016/j.chemgeo.2008.07.025
Galehouse, J.S., 1971. Point-counting. [In:] R.E. Carver (Ed.): Procedures in sedimentary petrology. Wiley-Interscience, New York, 385-407.
Gallois, R.W., 2004. The type section of the junction of the Otter Sandstone Formation and the Mercia Mudstone Group (mid Triassic) at Pennington Point, Sidmouth. Geoscience in south-west England 11, 51-58.
Gerdes, A. & Zeh, A., 2006. Combined U-Pb and Hf isotope LA-(MC)-ICP-MS analyses of detrital zircons: comparison with SHRIMP and new constraints for the provenance and age of an Armorican metasediment in central Germany. Earth and Planetary ScienceLetters 249, 47-61. DOI: https://www.doi.org/10.1016/j.epsl.2006.06.039
Guerrot, C. & Peucat, J.J., 1990. U-Pb geochronology of the Upper Proterozoic Cadomian orogeny in the northern Armorican Massif, France. [In:] D’Lemos, R.S., Strachan, R.A. & Topley, C.C. (Eds): The Cadomian orogeny. Geological Society, London, Special Publications 51, 13-26. DOI: https://www.doi.org/10.1144/GSL.SP.1990.051.01.02
Hallsworth, C.R., Morton, A.C., Claoué-Long, J. & Fanning, C.M., 2000. Carboniferous sand provenance in the Pennine Basin, UK: constraints from heavy mineral and detrital zircon age data. Sedimentary Geology 137, 147-185. DOI: https://www.doi.org/10.1016/S0037-0738(00)00153-6
Henry, D.J. & Guidotti, C.V., 1985. Tourmaline as a petrogenetic indicator mineral: an example from the staurolite-grade metapelites of NW Maine. American Mineralogist 70, 1-15.
Holloway, S., Milodowski, A.E., Strong, G.E. & Warrington, G., 1989. The Sherwood Sandstone Group of the Wessex Basin, southern England. Proceedings of the Geologists Association 100, 383-394. DOI: https://www.doi.org/10.1016/S0016-7878(89)80056-2
Hounslow, M.W. & Ruffell, A.H., 2006. Triassic: seasonal rivers, dusty deserts and saline lakes. [In:] P.J. Brenchley & P.F. Rawson (Eds): Geology of England and Wales. Geological Society, London, 295-324. DOI: https://www.doi.org/10.1144/GOEWP.13
Hounslow, M.W. & McIntosh, G., 2003. Magnetostratigraphy of the Sherwood Sandstone Group (Lower and Middle Triassic), South Devon, UK: detailed correlation of the marine and non-marine Anisian. Palaeogeography, Palaeoclimatology, Palaeoecology 193, 325-348. DOI: https://www.doi.org/10.1016/S0031-0182(03)00235-9
Inglis, J.D., Samson, S.D., D’Lemos, R.S. & Hamilton, M., 2004. U-Pb geochronological constraints on the tectonothermal evolution of the Paleoproterozoic basement of Cadomia, La Hague, NW France. Precambrian Research 134, 293-315. DOI: https://www.doi.org/10.1016/j.precamres.2004.07.003
Jackson, S., Pearson, N., Griffin, W. & Belousova, E., 2004. The application of laser ablation - inductively coupled plasma - mass spectrometry to in situ U-Pb zircon geochronology. Chemical Geology 211, 47-69. DOI: https://www.doi.org/10.1016/j.chemgeo.2004.06.017
Jeans, C.V., Reed, S.J.B. & Xing, M., 1993. Heavy mineral stratigraphy in the UK Trias: western approaches, onshore England and the central North Sea. [In:] J.R. Parker (Ed.): Petroleum geology of Northwest Europe -Proceedings of the 4th Conference. Geological Society, London, 609-624. DOI: https://www.doi.org/10.1144/0040609
Jones, D.G., Morton, A.C., Leng, M.J., Haslam, H.W., Milodowski, A.E., Strong, G.E. & Kemp, S.J., 2000. Provenance of the basin fill. [In:] J.A. Plant, D.G. Jones & H.W. Haslam (Eds): The Cheshire Basin: basin evolution, fluid movement and mineral resources in a Permo-Triasrift setting. British Geological Survey, Keyworth, UK, 90-124.
Jones, N.S. & Ambrose, K., 1994. Triassic sandy braidplain and aeolian sedimentation in the Sherwood Sandstone Group of the Sellafield area, west Cumbria. Proceedings of the Yorkshire Geological Society 50, 61-76. DOI: https://www.doi.org/10.1144/pygs.50.1.61
Leonard, A.J., Moore, A.G. & Selwood, B.E., 1982. Ventifacts from a deflation surface marking the top of the Budleigh Salterton Pebble Beds, east Devon. Proceedings of the Ussher Society 5, 333-339.
Lorsong, J.M. & Atkinson, C.D., 1995. Sedimentology andstratigraphy of Lower Triassic alluvial deposits, East Devoncoast. Excursion guide. Petroleum Group. Geological Society, London.
Lott, G.K. & Strong, G.E., 1982. The petrology and petrographyof the Sherwood Sandstone (?Middle Triassic) of the Winterborne Kingston Borehole, Dorset. Report of the Institute of Geological Sciences 81/3, 135-142.
Ludwig, K.R., 2003. Isoplot/Ex version 3: a geochronological toolkit for Microsoft Excel. Berkeley Geochronology Center, Special Publication, 4.
Ludwikowska-Kędzia, M., 2013. The composition of transparent heavy minerals in Quaternary sediments of the Kielce-Łagów valley (Holy Cross Mountains, Poland). Geologos 19 (this issue), 95-129. DOI: https://www.doi.org/10.2478/logos-2013-0007
Mange, M.A. & Maurer, H.F.W., 1992. Heavy minerals in colour. Chapman and Hall, London, 147 pp. DOI: https://www.doi.org/10.1007/978-94-011-2308-2
Mange, M.A. & Morton, A.C., 2007. Geochemistry of heavy minerals. [In:] M. Mange & D.T. Wright (Eds): Heavy minerals in use. Developments in Sedimentology 58, 345-391. DOI: https://www.doi.org/10.1016/S0070-4571(07)58013-1
Mange, M., Turner, P., Ince, D., Pugh, J. & Wright, D., 1999. A new perspective on the zonation and correlation of barren strata: an integrated heavy mineral and palaeomagnetic study of the Sherwood Sandstone Group, East Irish Sea Basin and surrounding areas. Journal of Petroleum Geology 22, 325-348. DOI: https://www.doi.org/10.1111/j.1747-5457.1999.tb00990.x
Marcinkowski, B. & Mycielska-Dowgiałło, E., 2013. Heavy-mineral analysis in Polish investigations of Quaternary deposits: a review. Geologos 19 (this issue), 5-23. DOI: https://www.doi.org/10.2478/logos-2013-0002
Mattinson, J.M., 2010. Analysis of the relative decay constants of 235U and 238U by multi-step CA-TIMS measurements of closed-system natural zircon samples. Chemical Geology 275, 186-198. DOI: https://www.doi.org/10.1016/j.chemgeo.2010.05.007
McKie, T. & Williams, B., 2009. Triassic palaeogeography and fluvial dispersal across the northwest European Basins. Geological Journal 44, 711-741. DOI: https://www.doi.org/10.1002/gj.1201
McKie, T., Aggett, J. & Hogg, A.J.C., 1998. Reservoir architecture of the upper Sherwood Sandstone, Wytch Farm field, southern England. [In:] J.R. Underhill (Ed.): Development, evolution and petroleum geology of the Wessex basin. Geological Society, London, Special Publications 133, 133-406. DOI: https://www.doi.org/10.1144/GSL.SP.1998.133.01.21
Miller, B.V., Samson, S.D. & D’Lemos, R.S., 2001. U-Pb geochronological constraints on the timing of plutonism, volcanism, and sedimentation, Jersey, Channel Islands, UK. Journal of the Geological Society (London) 158, 243-252. DOI: https://www.doi.org/10.1144/jgs.158.2.243
Morton, A.C., 2012. Value of heavy minerals in sediments and sedimentary rocks for provenance, transport history and stratigraphic correlation. [In:] P. Sylvester (Ed.): Quantitative mineralogy and microanalysis of sedimentsand sedimentary rocks. Mineralogical Association of Canada Short Course Series 42, 133-165.
Morton, A.C. & Hallsworth, C.R., 1994. Identifying provenance- specific features of detrital heavy mineral assemblages in sandstones. Sedimentary Geology 90, 241-256. DOI: https://www.doi.org/10.1016/0037-0738(94)90041-8
Morton, A.C., Fanning, C.M. & Jones, N.S., 2010. Variscan sourcing of Westphalian (Pennsylvanian) sandstones in the Canonbie Coalfield, UK. Geological Magazine 147, 718-727. DOI: https://www.doi.org/10.1017/S0016756810000014
Nasdala, L., Hofmeister, W., Norberg, N., Mattinson, J.M., Corfu, F., Dörr, W., Kamo, S.L., Kennedy, A.K., Kronz, A., Reiners, P.W., Frei, D., Košler, J., Wan, Y., Götze, J., Häger, T., Kröner, A. & Valley, J.W., 2008. Zircon M257 - a homogeneous natural reference material for the ion microprobe U-Pb analysis of zircon. Geostandards and Geoanalytical Research 32, 247-265. DOI: https://www.doi.org/10.1111/j.1751-908X.2008.00914.x
Preto, N., Kustatscherc, E. & Wignall, P.B., 2010. Triassic climates - state of the art and perspectives. Palaeogeography, Palaeoclimatology, Palaeoecology 290, 1-10. DOI: https://www.doi.org/10.1016/j.palaeo.2010.03.015
Purvis, K. & Wright, V.P., 1991. Calcretes related to phreatophytic vegetation from the Middle Triassic Otter Sandstone of southwestern England. Sedimentology 38, 539-551. DOI: https://www.doi.org/10.1111/j.1365-3091.1991.tb00366.x
Roach, R.A., Lees, G.J. & Shufflebotham, M.M., 1990. Brioverian volcanism and Cadomian tectonics, Baie de St Brieuc, Brittany: stages in the evolution of a late Precambrian ensialic basin. [In:] R.S. D’Lemos, R.A. Strachan & C.C. Topley (Eds): The Cadomian orogeny. Geological Society, London, Special Publications 51, 41-67. DOI: https://www.doi.org/10.1144/GSL.SP.1990.051.01.04
Ruffell, A. & Shelton, R., 1999. The control of sedimentary facies by climate during phases of crustal extension; examples from the Triassic of onshore and offshore England and Northern Ireland. Journal of the Geological Society 156, 779-789. DOI: https://www.doi.org/10.1144/gsjgs.156.4.0779
Samson, S.D. & D’Lemos, R.S., 1998. U-Pb geochronology and Sm-Nd isotopic composition of Proterozoic gneisses, Channel Islands, UK. Journal of the Geological Society 155, 609-618. DOI: https://www.doi.org/10.1144/gsjgs.155.4.0609
Samson, S.D., D’Lemos, R.S., Miller, B.V. & Hamilton, M.A., 2005. Neoproterozoic palaeogeography of the Cadomia and Avalon terranes: constraints from detrital zircon U-Pb ages. Journal of the Geological Society 162, 65-71. DOI: https://www.doi.org/10.1144/0016-764904-003
Schulmann, K., Schaltegger, U., Jezek, J., Thompson, A.B. & Edel, J.-B., 2002. Rapid burial and exhumation during orogeny: thickening and synconvergent exhumation of thermally-weakened and thinned crust (Variscan orogen in western Europe). American Journal of Science 302, 856-879. DOI: https://www.doi.org/10.2475/ajs.302.10.856
Sircombe, K.N., 2004. AgeDisplay: an EXCEL workbook to evaluate and display univariate geochronological data using binned frequency histograms and probability density distributions. Computers & Geosciences 30, 21-31. DOI: https://www.doi.org/10.1016/j.cageo.2003.09.006
Sláma, J., Košler, J., Condon, D.J., Crowley, J.L., Gerdes, A., Hanchar, J.M., Horstwood, M.S.A., Morris, G.A., Nasdala, L., Norberg, N., Schaltegger, U., Schoene, B., Tubrett, M.N. & Whitehouse, M.J., 2008. Plešovice zircon - a new natural reference material for U-Pb and Hf isotopic microanalysis. Chemical Geology 249, 1-35. DOI: https://www.doi.org/10.1016/j.chemgeo.2007.11.005
Smith, S.A., 1990. The sedimentology and accretionary styles of an ancient gravel-bed stream: the Budleigh Salterton Pebble Beds (Lower Triassic), southwest England. Sedimentary Geology 67, 199-219. DOI: https://www.doi.org/10.1016/0037-0738(90)90035-R
Smith, S.A. & Edwards, R.A. 1991. Regional sedimentological variations in Lower Triassic fluvial conglomerates (Budleigh Salterton Pebble Beds), southwest England: some implications for palaeogeography and basin evolution. Geological Journal 26, 65-83. DOI: https://www.doi.org/10.1002/gj.3350260105
Stacey, J.S. & Kramers, J.D., 1975. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth and Planetary Science Letters 26, 207-221. DOI: https://www.doi.org/10.1016/0012-821X(75)90088-6
Steel, R.J. & Thompson, D.B., 1983. Structures and textures in Triassic braided stream conglomerates (‘Bunter’ Pebble Beds) in the Sherwood Sandstone Group, North Staffordshire, England. Sedimentology 30, 341-367. DOI: https://www.doi.org/10.1111/j.1365-3091.1983.tb00677.x
Svendsen, J.B. & Hartley, N.R., 2001. Comparison between outcrop-spectral gamma ray logging and whole rock geochemistry: implications for quantitative reservoir characterization in continental sequences. Marine and Petroleum Geology 18, 657-670. DOI: https://www.doi.org/10.1016/S0264-8172(01)00022-8
Svendsen, J.B. & Hartley, N.R., 2002. Synthetic heavy mineral stratigraphy: applications and limitations. Marine and Petroleum Geology 19, 389-405. DOI: https://www.doi.org/10.1016/S0264-8172(02)00010-7
Thomas, H.H., 1902. Mineralogical constitution of the finer material of the Bunter Pebble-Bed in the west of England. Quarterly Journal of the Geological Society of London 58, 620-632. DOI: https://www.doi.org/10.1144/GSL.JGS.1902.058.01-04.35
Thomas, H.H., 1909. A contribution to the petrography of the New Red Sandstone in the west of England. Quarterly Journal of the Geological Society of London 65, 229-244. DOI: https://www.doi.org/10.1144/GSL.JGS.1909.065.01-04.18
Thompson, D.B., 1970. Sedimentation of the Triassic (Scythian) red pebbly sandstones in the Cheshire Basin and its margins. Geological Journal 7, 183-216. DOI: https://www.doi.org/10.1002/gj.3350070111
Tischendorf, G., Förster, H.-J., Frischbutter, A., Kramer, W., Schmidt, W. & Werner, C.D., 1995. Igneous activity. [In:] R.D. Dallmeyer, W. Franke & K. Weber (Eds): Pre-Permian geology of central and eastern Europe. Springer-Verlag, Berlin, 249-259. DOI: https://www.doi.org/10.1007/978-3-642-77518-5_25
Tyrrell, S., Haughton, P.D.W., Souders, A.K., Daly, J.S. & Shannon, P.M., 2012. Large-scale, linked drainage systems in the NW European Triassic: insights from the Pb isotopic composition of detrital K-feldspar. Journalof the Geological Society 169, 279-295. DOI: https://www.doi.org/10.1144/0016-76492011-104
Van Loon, A.J. & Mange, M.A., 2007. “In situ” dissolution of heavy minerals through extreme weathering, and the application of the surviving assemblages and their dissolution characteristics to correlation of Dutch and German silver sands. [In:] M.A. Mange & D.T. Wright (Eds): Heavy minerals in use. Developments in Sedimentology 58, 189-213. DOI: https://www.doi.org/10.1016/S0070-4571(07)58006-4
Vidal, P., Auvray, B., Charlot, R. & Cogné, J., 1981. Precambrian relicts in the Armorican Massif: their age and role in the evolution of the western and central European Cadomian-Hercynian belt. Precambrian Research 14, 1-20. DOI: https://www.doi.org/10.1016/0301-9268(81)90032-2
Warrington, G. & Ivimey-Cooke, H.C., 1992. Triassic. [In:] J.C.W. Cope, J.K. Ingham & P.F. Rawson (Eds): Atlasof palaeogeography and lithofacies. Geological Society, London, Memoir 13, 97-106. DOI: https://www.doi.org/10.1144/GSL.MEM.1992.013.01.11
Wills, L.J., 1956. Concealed coalfields. Blackie, London, 208 pp.
Wills, L.J., 1970. The Triassic succession in the central Midlands in its regional setting. Quarterly Journal ofthe Geological Society of London, 126, 225-283. DOI: https://www.doi.org/10.1144/gsjgs.126.1.0225
Woronko, B., Rychel, J., Karasiewicz, M.T., Ber, A., Krzywicki, T., Marks, L. & Pochocka-Szwarc, K., 2013. Heavy and light minerals as a tool for reconstruction of depositional environments: an example from the Jałówka site (northern Podlasie region, NE Poland). Geologos 19 (this issue), 47-66. DOI: https://www.doi.org/10.2478/logos-2013-0004
Wright, V.P., Marriott, S.B. & Vanstone, S.D., 1991. A reg palaeosol from the Lower Triassic of south Devon: stratigraphic and palaeoclimatic implications. Geological Magazine 128, 517-523. DOI: https://www.doi.org/10.1017/S0016756800018653
License
This content is open access.