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The Geology and Petrology of the Cockburn Law Intrusion, Berwickshire

Published online by Cambridge University Press:  01 May 2009

H. G. Midgley
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X.summary

The Cockburn Law intrusion is a small sheeted boss of late Caledonian age, intruded into Silurian rocks of Llandovery age.

The following are the chief stages in its formation:—

1. The earliest igneous activity was the intrusion of basic rock, now only found as xenoliths. This intrusion was followed at some later stage by—

2. The main plutonic magma which assimilated the basic rock and country rock to produce the following hybrids—

(a) Hybrid hypersthene diorite, from contamination by the Silurian pelites and greywackes.

(b) Hybrid diopside diorite, from contamination by the basic rock.

(c) Hybrid pyroxene diorite, from contamination by material from both basic igneous and sedimentary rocks.

3. After the consolidation of the marginal hybrids the main body of the magma began to solidify, but had time to differentiate in place to give a composition ranging from adamellite through granite to granophyric microgranite.

4. The heat from the intrusion metamorphosed the Silurian sediments to biotite cordierite hornfels which grade insensibly into the hybrid hypersthene diorite.

5. Following the consolidation of the plutonic mass there was considerable activity by vapours to form pneumatolytic products, while differentiation of the residual magma produced the aplitic, acidic, and lamprophyric dykes.

The intrusion may form a cupola from a bathylith, which may possibly belong to a series of bathyliths lying in a Caledonian direction from Newry to the Firth of Forth.

Type
Articles
Information
Geological Magazine , Volume 83 , Issue 2 , April 1946 , pp. 49 - 66
Copyright
Copyright © Cambridge University Press 1946

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References

XI. LIST of Works to which References is Made

Bowen, N. 1928. The Evolution of the Igneous Rocks. Princeton, p. 60.Google Scholar
Deer, W. A. 1935. The Cairnsmore of Carsphairn Igneous Complex. Quart. Journ. Geol. Soc., xci, 47.Google Scholar
Gardiner, C. I., and Reynolds, S. H. 1932. The Loch Doon Granite Area, Galloway. Quart. Journ. Geol. Soc., lxxxviii, 1.Google Scholar
Gardiner, C. I., and Reynolds, S. H. 1937. Cairnsmore of Fleet Granite and Metamorphic Aureole. Geol. Mag., lxxiv, 289.Google Scholar
Geikie, , and others. 1910. The Geology of East Lothian. Mem. Geol. Surv. Scotland.Google Scholar
Harker, A. 1919. Petrology for Students. 7th edn. p. 219. Cambridge.Google Scholar
Jhingran, A. G. 1942. The Cheviot Granite. Quart. Journ. Geol. Soc., xcviii, 241.Google Scholar
Johannsen, A. 1937. Petrography, II. p. 208. University of Chicago Press.Google Scholar
MacGregor, A. G. 1930. Chap. III and IV in The Geology of North Ayrshire. Mem. Geol. Surv. Scotland.Google Scholar
MacGregor, M. 1937. The Western part of the Criffel-Dalbeattie Igneous Complex. Quart. Journ. Geol. Soc., xciii, 457.Google Scholar
MacGregor, M. 1938. The Evolution of the Criffel-Dalbeattie Quartz-diorite. A study in Granitization. Geol. Mag., lxxv, 481.Google Scholar
Nockolds, S. R. 1931. The Dhoon (Isle of Man) granite. Min. Mag., xxii, 494.Google Scholar
Read, H. H. 1935. The Gabbros and associated Xenolithic Complexes of the Haddo House District, Aberdeenshire. Quart. Journ. Geol. Soc., xci, 601.Google Scholar
Reynolds, D. L. 1934. The Eastern End of the Newry Complex. Quart. Journ. Geol. Soc., xc, 585.CrossRefGoogle Scholar
Stevenson, W. 1849. The Geology of Cockburnlaw and the adjoining District in Berwickshire. Trans. Roy. Soc. Edinb., xvi, 33.Google Scholar
Tilley, C. E. 1924. Contact Metamorphism in the Comrie area. Quart. Journ. Geol. Soc., lxxx, 58.Google Scholar
Walker, F. 1925. Four Granitic Intrusions in South-Eastern Scotland. Trans. Edinb. Geol. Soc., xi, 357–365.CrossRefGoogle Scholar
Walker, F. 1928. The Plutonic Intrusions of the Southern Uplands East of the Nith Valley. Geol. Mag., lxv, 153–162.Google Scholar