Hostname: page-component-7c8c6479df-r7xzm Total loading time: 0 Render date: 2024-03-26T22:19:15.877Z Has data issue: false hasContentIssue false

Modern carbonate marine-sands in estuaries of southwest England

Published online by Cambridge University Press:  01 May 2009

J. R. Merefield
Affiliation:
Department of Geology, The University, Exeter, Devon, EX4 4QE

Summary

Large deposits of marine-sand occur in the Taw, Camel and Hayle estuaries of north Devon and Cornwall. Total carbonate concentrations reach 67% in the Hayle, 62% in the Camel, and 40% in the Taw. Well mixed, the sands contain modern skeletal debris of consistent composition, which persists up to 18 km and 12 km landward from the mouths of the Taw and Camel estuaries. Although primarily a molluscan sand, remains of barnacles, bryozoans, echinoids, foraminifera, sponge spicules, decapods and coralline algae are common. Carbonate mineralogy provided by these components (on a 100% carbonate basis) consists of 45% aragonite, 38% low Mg-calcite and 17% high Mg-calcite. Two estuaries of the southeast coast of Devon (the Exe and Teign) contain smaller carbonate concentrations of up to 9 and 14%. Values are low there owing to dilution by readily eroded cliff-talus from local exposures of New Red Sandstone. These Permo-Triassic sediments provide carbonate lithoclasts, however, which supplement the modern biogenic supply. Strontium values have been used to estimate the extent of carbonate lithoclasts supplied to the Exe and Teign. The present source of marine-sand of estuaries in southwest England is considered to be mostly near-shore detritus supplemented by eroded cliff-talus, derived largely from local outcrops. Once this material enters the estuarine regime it is available as a supply of sediment for further up-estuary transport.

Type
Articles
Copyright
Copyright © Cambridge University Press 1982

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

Banner, F. T. 1979. Sediments of the north-western European shelf. Elsevier Oceanography Series vol. 24 A, pp. 271300.Google Scholar
Belderson, R. H., Kenyon, N. H. & Stride, A. H. 1971. Holocene sediments on the continental shelf west of the British Isles. In ICSU/SCOR Working Party 31 Symposium, Cambridge 1970: The Geology of East Atlantic Continental Margin, vol. 2. Europe (ed. Delany, F. M.). Inst. Geol. Sci. Rept. no. 70/14, pp. 161–70.Google Scholar
Blackmon, P. D. & Todd, R. 1959. Mineralogy of some foraminifera as related to their classification and ecology. J. Paleont. 33, 115.Google Scholar
Bouysse, P., Lann, F. L. & Scolari, G. 1979. Les sédiments superficiels des approches occidentales de La Manche. Mar. Geol. 29, 107–35.CrossRefGoogle Scholar
Channon, R. D. & Hamilton, D. 1976. Wave and tidal current sorting of shelf sediments southwest of England. Sedimentology 23, 1742.CrossRefGoogle Scholar
Chave, K. E. 1952. A solid solution between calcite and dolomite. J. Geol. 60, 190–2.Google Scholar
Chave, K. E. 1964. Skeletal durability and preservation. In Approaches to Paleoecology (ed. Imbrie, J. and Newell, N. D.), pp. 377–87. New York: John Wiley.Google Scholar
Codrington, T. 1898. On some submerged rock valleys in south Wales, Devon and Cornwall. Q. Jl geol. Soc. Lond. 54, 251–78.CrossRefGoogle Scholar
Cosgrove, M. E. 1973. The geochemistry and mineralogy of the Permian Red Beds of southwest England. Chem. Geol. 11, 3147.CrossRefGoogle Scholar
Culver, S. J. 1980. Differential two-way sediment transport in the Bristol Channel and Severn Estuary, U.K. Mar. Geol. 34, M 3943.Google Scholar
Culver, S. J. & Banner, F. T. 1979. The significance of derived pre-Quaternary foraminifera in Holocene sediments of the northcentral Bristol Channel. Mar. Geol. 29, 187207.CrossRefGoogle Scholar
De La Beche, H. T. 1839. Report on the geology of Cornwall, Devon and west Somerset. Mem. geol. Surv. U.K.Google Scholar
Donovan, D. T., Savage, R. J. G., Stride, A. H. & Stubbs, A. R. 1961. Geology of the floor of the Bristol Channel. Nature, Lond. 189, 51–2.Google Scholar
Driscol, E. G. 1967. Experimental field study of shell abrasion. J. sedim. Petrol. 37, 1117–23.Google Scholar
Durrance, E. M. 1969. The buried channels of the Exe. Geol. Mag. 106, 174–89.CrossRefGoogle Scholar
Durrance, E. M. 1971. The buried channel of the Teign estuary. Proc. Ussher Soc. 2, 299306.Google Scholar
Edmonds, E. A., Williams, B. J. & Taylor, R. T. 1979. Geology of Bideford and Lundy Island. Mem. geol. Surv. U.K.Google Scholar
Evans, D. J. & Thompson, M. S. 1979. The geology of the central Bristol Channel and the Lundy area, Southwestern Approaches, British Isles. Proc. Geol. Ass. 90, 120.CrossRefGoogle Scholar
Force, L. M. 1969. Calcium carbonate size distribution on the west Florida shelf and experimental studies on the microarchitectural control of skeletal breakdown. J. sedim. Petrol. 39, 902–34.Google Scholar
Gavish, E. & Friedman, G. M. 1973. Quantitative analysis of calcite and Mg-calcite by X-ray diffraction: effect of grinding on peak height and peak area. Sedimentology 20, 437–48.Google Scholar
Goldsmith, J. R., Graf, D. L. & Heard, H. C. 1961. Lattice constants of the calcium-magnesium carbonates. Am. Miner. 46, 453–7.Google Scholar
Guilcher, A. 1964. La sédimentation sous-marine dans la partie orientale de la Rade de Brest, Bretagne. In Developments in Sedimentology, vol. 1 (ed. Straaten, L. M. J. U. van), pp. 148–56.Google Scholar
Hallam, A. & Price, N. B. 1968. Environmental and biochemical control of strontium in shells of Cardium edule. Geochim. cosmochim. Acta. 32, 319–28.Google Scholar
Hamilton, D., Sommerville, J. H. & Stanford, P. N. 1980. Bottom currents and shelf sediments, southwest of Britain. Sediment. Geol. 26, 115–38.CrossRefGoogle Scholar
Hawkins, A. B. 1971. Sea level changes around southwest England. Colston Pap. 23, 6788.Google Scholar
Hjulström, F. 1935. Studies of the morphological activity of rivers as illustrated by the River Fyris. Bull. geol. Instn. Univ. Uppsala. 25, 221527.Google Scholar
Hosking, K. F. G. & Ong, P. 1963. The distribution of tin and certain other heavy metals in the superficial portions of the Gwithian/Hale beach of west Cornwall. Proc. Ussher Soc. 1, 41–3.Google Scholar
Inglis, C. C. & Allen, F. H. 1957. The regimen of the Thames estuary as affected by currents, salinities’ and river flow. Proc. Instn. civ Engrs. 7, 827–78.Google Scholar
Jones, W. C. & Jenkins, D. A. 1970. Calcareous sponge spicules: a study of magnesian calcites. Calcif. Tissue Res. 4, 314–29.CrossRefGoogle ScholarPubMed
Kenyon, N. H. & Stride, A. H. 1970. The tide-swept continental shelf sediments of the Shetland Islands and France. Sedimentology 14, 159–73.Google Scholar
Lees, A. 1975. Possible influence of salinity and temperature on modern shelf carbonate sedimentation. Mar. Geol. 19, 159–98.Google Scholar
Leonard, J. E., Cameron, B., Pilkey, O. H. & Friedman, G. M. 1981. Evaluation of cold-water carbonates as a possible paleoclimatic indicator. Sediment. Geol. 28, 128.Google Scholar
MacFarlane, P. B. 1955. Survey of two drowned river valleys in Devon. Geol. Mag. 92, 419–29.CrossRefGoogle Scholar
Meade, R. H. 1969. Landward transport of bottom sediments in estuaries of the Atlantic Coastal Plain. J. sedim. Petrol. 39, 222–34.Google Scholar
Meade, R. H. 1972. Transport and deposition of sediments in estuaries. Mem. geol. Soc. Am. 133, 91120.Google Scholar
Merefield, J. R. 1976. Barium build-up in the Teign Estuary. Mar. Pollut. Bull. 7, 214–16.CrossRefGoogle Scholar
Merefield, J. R. 1978. Trace elements as indicators of sediments transport in some estuaries of south-west England. (Abstract). Proc. Ussher Soc. 4, 219.Google Scholar
Merefield, J. R. 1981(a). Littoral carbonates of south-west England: preliminary observations on mineralogy and geochemistry. Proc. Ussher Soc. 5, 235–7.Google Scholar
Merefield, J. R. 1981(b). Caesium in the up-estuary transport of sediments. Mar. Geol. 39, M 4555.Google Scholar
Milliman, J. D. 1974. Marine Carbonates: Recent Sedimentary Carbonates, vol. 1. Berlin, Heidelberg, New York: Springer Verlag.CrossRefGoogle Scholar
Milliman, J. D. & Bornhold, B. D. 1973. Peak height versus peak intensity analysis of X-ray diffraction data. Sedimentology 20, 445–8.CrossRefGoogle Scholar
Milliman, J. D., Gastner, M. & Muller, J. 1971. Utilization of magnesium in coralline algae. Bull. geol. Soc. Am. 82, 573–80.Google Scholar
Murray, J. W. & Hawkins, A. B. 1976. Sediment transport in the Severn estuary during the past 8000–9000 years. J. geol. Soc. Lond. 132, 385–98.CrossRefGoogle Scholar
Murray, J. W., Sturrock, S. & Western, J. 1982. Suspended load transport of foraminiferal tests in a tide-and wave-swept sea. J. Foraminer. Res. 12, 5165.Google Scholar
Noll, W. 1934. Geochemie des Strontiums mit Bemerkungen zur Geochemie des Bariums. Chem. Erde 8, 507–60.Google Scholar
Norrish, K. & Hutton, J. T. 1964. Preparation of samples for analysis by X-ray fluorescent spectrography. C.S.I.R.O. Division of Soils. Report 3/64, Adelaide.Google Scholar
Postma, H. 1967. Sediment transport and sedimentation in the estuarine environment. In Estuaries (ed. Lauff, G. H.), pp. 158–79. Am. Assoc. Adv. Sci. Pub. 83.Google Scholar
Rucker, J. B. & Valentine, J. W. 1961. Salinity response of trace element concentration in Grassostrea virginica. Nature, Lond. 190, 1099–100.CrossRefGoogle Scholar
Salmon, R. 1973. Builders take away the Cornish coast. Observer Mag. 22/4, 35.Google Scholar
Schopf, T. J. M. & Manheim, F. T. 1967. Chemical composition of Ectoprocta (Bryozoa). J. Paleont. 41, 1197–225.Google Scholar
Sollas, W. J. 1883. The estuaries of the Severn and its tributaries: an enquiry into the nature and origin of their tidal sediment and alluvial flats. Q. J. geol. Soc. Lond. 39, 611–26.CrossRefGoogle Scholar
Spratt, T. 1856. An Investigation of the Movements of Teignmouth Bar. London.Google Scholar
Stuart, A. & Simpson, B. 1936. The shore sands of Cornwall & Devon from Land's End to the Taw-Torridge estuary. R. geol. Soc. Corn. 17, 1340.Google Scholar
Thomas, J. M. 1980. Sediments and sediment transport in the Exe estuary. In Essays on the Exe Estuary (ed. Boalch, G. T.), pp. 7387. Exeter: Devon Ass. Special Vol. 2.Google Scholar
Vanny, J. R. 1965. Etude sédimentologique du Mor Bras, Bretagne. Mar. Geol. 3, 195222.CrossRefGoogle Scholar
Vinogradov, A. P. 1953. The elementary chemical composition of marine organisms. Sears Found. Marine Res. Mem. II.Google Scholar
Yim, W. W. S. 1976. Heavy metal accumulation in estuarine sediments in a historical mining area of Cornwall. Mar. Pollut. Bull. 7, 147–50.Google Scholar