Hostname: page-component-cd9895bd7-jkksz Total loading time: 0 Render date: 2024-12-25T07:49:12.247Z Has data issue: false hasContentIssue false
  • English
  • Français

Folding and pressure solution in a laminated calcite-quartz vein from the Silurian slates of the Llangollen region of N Wales

Published online by Cambridge University Press:  01 May 2009

R. Nicholson
R. Nicholson
Affiliation:
Department of Geology, The University, Manchester
Get access Rights & Permissions [Opens in a new window]

Summary

Folds of a 12 mm thick calcite-rich vein, embedded in slate and with a primary planar fabric of parallel, thin and plate-like calcite crystals, or laminae, have a vein thickness/arc length ratio near 1. Folds were first entirely dependent for development on intra-laminar strain and inter-laminar sliding. As limb dips increased, however, pressure solution began to thin laminae in limb regions only. As adjacent inter-laminar surfaces met at fold inflexion points, where laminae were first cut through, loss on fabric-cutting surfaces began to replace inter-laminar pressure solution. The resulting stylolites grew across the vein in fold limbs, at the limit eliminating them. In contrast, in folded equigranular calcite rocks stylolites are widely developed in both limbs and hinges, and eventual fold collapse through late stage concentration of pressure solution takes place in fold hinges and not limbs.

Type
Articles
Information
Geological Magazine , Volume 115 , Issue 1 , January 1978 , pp. 47 - 54
Copyright
Copyright © Cambridge University Press 1978

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

Biot, M. A. 1964.Theory of internal buckling of a confined multilayered structure. Bull. geol. Soc. Am. 75, 563–8.CrossRefGoogle Scholar
Biot, M. A. 1965(a). Theory of similar folding of the first and second kind. Bull. geol. Soc. Am. 76, 251–8.CrossRefGoogle Scholar
Biot, M. A. 1965(b). Mechanics of Incremental Deformations, New York: Wiley.CrossRefGoogle Scholar
Chadwick, P. 1975. A psychological analysis of observation in geology. Nature, Lond. 256, 570–3.CrossRefGoogle Scholar
Cottrell, A. H. 1964. The Mechanical Properties of Metals. New York: Wiley.Google Scholar
Elliott, D. 1973. Diffusion flow laws in metamorphic rocks. Bull. geol. Soc. Am. 84, 2645–64.2.0.CO;2>CrossRefGoogle Scholar
Fletcher, R. C. 1977. Quantitative theory for metamorphic differentiation in development of crenulation cleavage. Geology 5, 185–7.2.0.CO;2>CrossRefGoogle Scholar
Groshong, R. H. M. 1972. Strain calculated from twinning in calcite. Bull. geol. Soc. Am. 83, 2025–38.CrossRefGoogle Scholar
Groshong, R. H. M. 1975. Strain, fractures, and pressure solution in natural single-layer folds. Bull. geol. Soc. Am. 86, 1363–76.2.0.CO;2>CrossRefGoogle Scholar
Nettle, J. T. 1964. Fabric analysis of a deformed vein. Geol. Mag. 101, 220–7.CrossRefGoogle Scholar
Nicholson, R. 1964. Fabric analysis of a deformed vein. Geol. Mag. 101, 474.CrossRefGoogle Scholar
Nicholson, R. 1966. The problem of origin, deformation and recrystallization of calcite-quartz bodies. Geol. J. 5, 117–26.CrossRefGoogle Scholar
Ramsay, J. G. 1967. Folding and fracturing of rocks. New York: McGraw-Hill.Google Scholar
Rutter, E. H. 1974. The influence of temperature, strain rate and interstitial water in the experimental deformation of calcite rocks. Tectonophysics 22, 311–34.CrossRefGoogle Scholar
Sherwin, J. A. & Chapple, H. 1968. Wave-lengths of single layer folds: A comparison between theory and observation. Am. J. Sci. 266, 167–79.CrossRefGoogle Scholar
Warren, P. T., Harrison, R. K., Wilson, H. E., Smith, E. G. & Nutt, M. J. C. 1970. Tectonic ripples and associated minor structures in the Silurian rocks of Denbighshire, North Wales. Geol. Mag. 107, 51–60.CrossRefGoogle Scholar
Wedd, C. B., Smith, B. & Wills, L. J. 1927. The geology of the country around Wrexham. Mem. Geol. Surv. England and Wales.Google Scholar