Hostname: page-component-78c5997874-4rdpn Total loading time: 0 Render date: 2024-11-09T19:29:23.575Z Has data issue: false hasContentIssue false
  • English
  • Français

X.—A Gravity Survey in Ayrshire and its Geological Interpretation*

Published online by Cambridge University Press:  06 July 2012

Adam C. McLean
Adam C. McLean
Affiliation:
Department of Geology, University of Glasgow.
Get access Rights & Permissions [Opens in a new window]

Synopsis

Bouguer anomaly maps covering most of Ayrshire at a density of about one station per sq. km., show a close relationship between anomalies and the distribution of the Upper Palæozoic rocks in the area south of the Inch-gotrick Fault, but are less clearly interpreted to the north, where thick dense igneous masses are present.

In central and south Ayrshire the gravity field may be largely interpreted in terms of the known density-contrasts at the interfaces separating Upper and Lower Old Red Sandstone, and Lower Old Red Sandstone and Lower Palæozoic rocks. The major structure, the Mauchline Basin, is reflected clearly in the largest anomaly, and there is evidence of a culmination of its south-western limb near Kirkoswald. The important N.E.–S.W. faults also give rise to large anomalies, which may be connected with the known geology. It is inferred that they moved as normal faults in Carboniferous times, and that the adjacent synclines are essentially sags associated with the fault displacements. There is geophysical evidence that both the Southern Upland and Kerse Loch Faults existed in Middle O.R.S. (proto-Armorican) times. It is concluded that a hypothesis of N.–S. Armorican stress is not valid in south Ayrshire.

In north Ayrshire, many of the anomalies are best explained by changes of thickness of the Millstone Grit lavas and of the Clyde Plateau lavas, and by the presence of thick dolerite intrusions. Additional evidence is needed, however, before final conclusions may be drawn.

Type
Research Article
Information
Earth and Environmental Science Transactions of The Royal Society of Edinburgh , Volume 66 , Issue 10 , 1966 , pp. 239 - 265
Copyright
Copyright © Royal Society of Edinburgh 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 to Literature

Anderson, E. M., 1951. The dynamics of faulting. Edinburgh. 2nd Edn.Google Scholar
Anderson, E. M. et al. , 1925. “The Economic Geology of the Ayrshire Coalfields, Area II”, Mem. Geol. Surv. U.K.Google Scholar
Bullerwell, W., 1952. “Gravimeter Observations Comparing Pendulum Stations at Cambridge, York, Newcastle-upon-Tyne, Edinburgh and Aberdeen”, Mon. Not. Roy. Astr. Soc. Geophys. Suppl., 6, 303–315.Google Scholar
Cloos, H., 1931. “Zur Experimentellen Tektonik”, Naturwissenschaften, 19, 242–247.CrossRefGoogle Scholar
Cloos, E., 1955. “Experimental Analysis of Fracture Patterns”, Bull. Geol. Soc. Amer., 66, 241–256.CrossRefGoogle Scholar
Eyles, V. A., Simpson, J. B., and MacGregor, A. G., 1930. “Economic Geology of the Ayrshire Coalfields, Area III”, Mem. Geol. Surv. U.K.Google Scholar
Eyles, V. A., Simpson, J. B., and MacGregor, A. G., 1949. “Geology of Central Ayrshire”, 2nd Edn. Mem. Geol. Surv. U.K.Google Scholar
George, T. N., 1951. “Hercynian Structures in Wales and Scotland”, Proc. Geol. Soc. Glasg., 21, 383.Google Scholar
Goguel, J., 1962. Tectonics, San Francisco. 2nd Edn. (translation).Google Scholar
Hubbert, M. K., 1948. “Line-integral Method of Computing Gravity”, Geophysics, 13, 215–225.CrossRefGoogle Scholar
Kelling, G., 1961. “The Stratigraphy and Structure of the Ordovician Rocks of the Rhinns of Galloway”, Quart. J. Geol. Soc. Lond., 117, 37–75.Google Scholar
Kennedy, W. Q., 1958. “The Tectonic Evolution of the Midland Valley of Scotland”, Trans. Geol. Soc. Glasg., 23, 106–133.CrossRefGoogle Scholar
Laubscher, H. P., 1956. “Structural and Seismic Deformations along Normal Faults in the Eastern Venezuelan Basin”, Geophysics, 21, 368–387.CrossRefGoogle Scholar
McLean, A. C., 1961 a. “Density Measurements of Rocks in South-West Scotland”, Proc. Roy. Soc. Edin., B, 68, 103–111.Google Scholar
McLean, A. C., 1961 b. “A Gravity Survey of the Sanquhar Coalfield”, Proc. Roy. Soc. Edin., B, 68, 112–127.Google Scholar
Patterson, E. M., 1954. “Notes on the Tectonics of Greenock-Largs Uplands and Cumbraes”, Trans. Geol. Soc. Glasg., 21, 430–435.CrossRefGoogle Scholar
Peach, B. N. et al. , 1871. Explanation of Sheet 15 (Scotland), Mem. Geol. Surv. U.K.Google Scholar
Richey, J. E.et al., 1930. “The Geology of North Ayrshire”, Mem. Geol. Surv. U.K.Google Scholar
Richey, J. E., 1925. “The Economic Geology of the Ayrshire Coalfields, Area I”, Mem. Geol. Surv. U.K.Google Scholar
Richter, C. F., 1958. “Elementary Seismology”, San Francisco.Google Scholar
Rolfe, W. D. L., 1962. “The Geology of the Hagshaw Hills Silurian Inlier”, Trans. Edin. Geol. Soc., 18, 240–69.CrossRefGoogle Scholar
Simpson, J. B., and MacGregor, A. G., 1932. “The Economic Geology of the Ayrshire Coalfields, Area IV”, Mem. Geol. Surv. U.K.Google Scholar
Simpson, J. B., and Richey, J. E., 1936. “The Geology of the Sanquhar Coalfield”, Mem. Geol. Surv. U.K.Google Scholar
Smith, A. E., 1951. “Graphic Adjustment by Least Squares”, Geophysics, 16, 222–227.CrossRefGoogle Scholar
Walton, E. K., 1961. “Some Aspects of the Succession and Structure in the Lower Palæozoic Rocks of the Southern Uplands of Scotland”, Geol. Rdsch., 50, 63–77.CrossRefGoogle Scholar
Williams, A., 1959. “A Structural History of the Girvan District, S. W. Ayrshire”, Trans. Roy. Soc. Edin., 63, 629–667.CrossRefGoogle Scholar