Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-13T00:52:51.733Z Has data issue: false hasContentIssue false
  • English
  • Français

Fold Structures in the Mylor Beds, near Porthleven, Cornwall

Published online by Cambridge University Press:  01 May 2009

Maurice Stone
Maurice Stone
Affiliation:
Department of Geology, University of Exeter, Exeter, Devon.
Get access Rights & Permissions [Opens in a new window]

Abstract

Early folds (F1) in the Mylor Beds are upright or overturned to the north-west and trend north-easterly. They are cut by a flat-lying cleavage (S2) which is related to small-scale recumbent folds (F2) superimposed on the steep limbs of the early folds. The sequence of development of folds can be found elsewhere in the Mylor-Gram-scatho Beds and also in the Lizard Head mica schists. It is shown that F2 folds and S2 cleavage resulted from vertical shortening, which is believed to have been caused by the superimposition of slide sheets. It is suggested that the previously accepted age order of the Mylor and Gramscatho Beds should be reversed.

Type
Articles
Information
Geological Magazine , Volume 103 , Issue 5 , October 1966 , pp. 440 - 460
Copyright
Copyright © Cambridge University Press 1966

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

REFERENCES

Cummins, W. A., and Shackleton, R. M., 1955. The Ben Lui recumbent syncline (S.W. Highlands). Geol. Mag., 92, 351–363.CrossRefGoogle Scholar
Dodson, M. H., 1960. Isotopic ages from the Lizard Peninsula, South Cornwall. Proc. geol. Soc. Lond., 1591, 133–136.Google Scholar
Dodson, M. H., 1962. Potassium-argon ages of some South-Western slates and phyllites. Proc. Ussher Soc., i, Part 1, 13–14.Google Scholar
SirFlett, J. S., 1946. Geology of the Lizard and Meneage. Mem. geol. Surv. U.K. (2nd Edit.).Google Scholar
Flett, J. S., and Hill, J. B., 1912. The geology of the Lizard and Meneage. Mem. geol. Surv. U.K.Google Scholar
Fleuty, M. J., 1964. The description of folds. Proc. Geol. Ass., 75, 461–492.CrossRefGoogle Scholar
Flinn, D., 1961. On deformation at thrust planes in Shetland and the Jotunheim area of Norway. Geol. Mag., 98, 245–256.CrossRefGoogle Scholar
Green, D. H., 1964. A restudy and re-interpretation of the geology of the Lizard Peninsuala, Cornwall. In Hosking, K. F. G., and Shrimpton, G. J. (Edit.): Present views of some aspects of the geology of Cornwall and Devon. R. geol. Soc. Corn., Penzance, pp. 87–114.Google Scholar
Green, U., and Sherborn, C. D., 1912. Note on the Pollurian-Trewavas coast section. Geol. Mag., N.S. Dec. 5, 9, 558–560.CrossRefGoogle Scholar
Green, U., 1913. On the general geological structure of western Cornwall, with a note on the Porthluney-Dodman section. Geol. Mag., N.S. Dec. 5, 10, 70–73.CrossRefGoogle Scholar
Hall, S., 1930. The geology of the Godolphin granite. A study of the coastal geology between Perranuthnoe and Loe Pool. Proc. Geol. Ass., 41, 117–147.CrossRefGoogle Scholar
Hendriks, E. M. L., 1937. Rock succession and structure in south Cornwall: a revision, with notes on the central European facies and Variscan folding there present. Q. Jl geol. Soc., Lond., 93, 322–360.CrossRefGoogle Scholar
Hendriks, E. M. L., 1959. A summary of present views on the structure of Cornwall and Devon. Geol. Mag., 96, 253–257.CrossRefGoogle Scholar
Hill, J. B., 1899. In Summ. Progr. geol. Surv., Gt. Br. for 1898, pp. 97–101.Google Scholar
Hill, J. B., 1900. In Summ. Progr. geol. Surv., Gt. Br. for 1899, pp. 88–95.Google Scholar
Hill, J. B., 1906a. In Summ. Progr. geol. Surv., Gt. Br. for 1905, pp. 24–27.Google Scholar
Hill, J. B., 1906b. On the relations between the older and new Palaeozoics of west Cornwall. Geol. Mag., N.S. Dec. 5, 3, 206–216.CrossRefGoogle Scholar
Hill, J. B., 1907. In Summ. Progr. geol. Surv., Gt. Br. for 1906, pp. 30–31.Google Scholar
Hill, J. B., 1913. The geology of northern Meneage. Proc. Geol. Ass., 24, 134–158.CrossRefGoogle Scholar
Hills, E. S., 1953. Outlines of structural geology. (3rd Edit.), London.Google Scholar
Hubbert, M. K., and Ruby, W. W., 1959. Role of fluid pressure in mechanics of overthrust faulting 1. Mechanics of fluid-filled porous solids and its application to overthrust faulting. Bull. geol. Soc. Am., 70, 115–166.Google Scholar
Lambert, J. L. M., 1959. Cross-folding in the Gramscatho Beds at Helford River, Cornwall. Geol. Mag., 96, 489–496.CrossRefGoogle Scholar
Ramsey, J. G., 1962. The geometry and mechanics of formation of “similar” type folds. J. Geol., 70, 309–327.CrossRefGoogle Scholar
de Sitter, L. U., 1954. Gravitational gliding tectonics. An essay in comparative structural geology. Am. J. Sci., 252, 321–344.CrossRefGoogle Scholar
de Sitter, L. U., 1957. Plis couchés. Bull. Soc. belge Géol., 66, 353–375.Google Scholar
de Sitter, L. U., 1958. Boudins and parasitic folds in relation to cleavage and folding. Geologie Mijnb., 20, 227–286.Google Scholar
Stone, M., 1960. The Tregonning-Godolphin granite. Abstr. Proc. 3rd Conf. Geol. Geomorph. S.W. England. R. geol. Soc. Corn., p. 13.Google Scholar
Stone, M., 1962. Vertical flattening in the Mylor Beds, near Porthleven, Cornwall. Proc. Ussher Soc., i, Part 1, 25–27.Google Scholar
Stone, M., and Lambert, J. L. M., 1956. Shear folding in the Mylor Beds, near Porthleven, Cornwall. Geol. Mag., 93, 331–335.CrossRefGoogle Scholar
Tilley, C. E., 1937. Anthophyllite-cordierite granulites of the Lizard. Geol. Mag., 74, 300–309.CrossRefGoogle Scholar
Turner, F. J., 1957. Lineation, symmetry, and internal movement in monoclinic tectonite fabrics. Bull. geol. Soc. Am., 68, 1–18.CrossRefGoogle Scholar
Williams, E., 1961. The deformation of confined, incompetent layers in folding. Geol. Mag., 98, 317–323.CrossRefGoogle Scholar
Wilson, G., 1951. The geology of the Tintagel area, north Cornwall. Q. Jl geol. Soc., Lond., 106, 393–432.CrossRefGoogle Scholar