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Microscopic and megascopic fabrics in the Skiddaw Group, Black Combe inlier, English Lake District

Published online by Cambridge University Press:  01 May 2009

Douglas G. Helm
Douglas G. Helm
Affiliation:
Geology Department, University Of London Goldsmith's College, New Cross, London, S.E.14.
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Summary

The rocks of the Skiddaw Group of the Black Combe inlier were subjected to low grade regional metamorphism during the D1 movementphase of an intra-Lower Ordovician orogenic episode. Mimetic recrystallisation of clay minerals parallel to the bedding was ubiquitous. Later, axial-plane cleavages were superimposed on this fabric. The nature of the cleavages and possible mechanism of their formation is discussed.

Silica has been mobilised on at least three occasions during the tectonic history of the inlier. In no case was this due to metasomatism but simply to metamorphic differentiation. The D1 veins are of either quartz, or quartz and chlorite whereas veins of later generations are of quartz alone.

Type
Articles
Information
Geological Magazine , Volume 106 , Issue 6 , December 1969 , pp. 587 - 594
Copyright
Copyright © Cambridge University Press 1969

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References

REFERENCES

Christie, J. M., & Raleigh, C. B. 1959. The origin of deformation lamellae in quartz., Am. J. Sci., 257, 385–407.CrossRefGoogle Scholar
Fleuty, M. J. 1964. The description of folds. Proc. Geol. Ass., 75, 461–492.CrossRefGoogle Scholar
Helm, D. G., In press. Stratigraphy and structure in the Black Combe inlier, English Lake District. Proc. Yorks. geol. Soc.Google Scholar
Orville, P. M. 1962. Alkali metasomatism and feldspars. Norsk geol. Tidsskr., 42 (2), 283—316.Google Scholar
Ramberg, H. 1952. The origin of metamorphic and metasomatic rocks, a treatise on re-crystallisation and replacement in the earth's crust. 317 p. Chicago Univ. Press.Google Scholar