Hostname: page-component-848d4c4894-cjp7w Total loading time: 0 Render date: 2024-07-07T14:28:24.888Z Has data issue: false hasContentIssue false
  • English
  • Français

XXII.—Silurian Greywackes in Peeblesshire

Published online by Cambridge University Press:  11 June 2012

Ewart Kendall Walton
Get access

Synopsis

Sedimentary structures in the greywackes of Peeblesshire, including graded bedding, cross-lamination and load-cast structures, are described and their origin discussed.

Petrographically the greywackes are poorly sorted sediments composed of a variety of minerals and rock fragments. The minerals include quartz, felspar, augite and horn-blende, mica and chlorite, while the dominant rock fragments are andesites, spilites, quartz-keratophyres and granites.

Three groups of greywackes are recognized according to their mineralogy. The first, the Pyroxenous group, contains augite and hornblende. Rocks of the second group, the Intermediate group, are without these minerals, while the third group consists of rocks rich in garnet—the Garnetiferous group. These mineralogical differences are reflected in differences in the chemical analyses of the three groups. From consideration of the chemical and modal analyses it is suggested that differences in source rocks have influenced the composition of the greywackes more than variations in the intensity of alteration due to weathering and transport.

It is concluded that the greywackes have been formed from the rapid erosion of a land mass largely covered by Ordovician volcanic rocks, but also with developments of lowgrade regionally metamorphosed rocks and others resembling Torridonian arkoses. Sedimentation features are due to accumulation controlled largely by the action of turbidity currents.

Type
Research Article
Information
Proceedings of the Royal Society of Edinburgh, Section B: Biological Sciences , Volume 65 , Issue 3 , 1955 , pp. 327 - 357
Copyright
Copyright © Royal Society of Edinburgh 1955

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

Bailey, E. B., 1930. “New light on sedimentation and tectonics”, Geol. Mag., 67, 77–92.CrossRefGoogle Scholar
Edwards, A. B., 1947 a. “The petrology of the Miocene sediments of the Aure Trough, Papua”, Proc. Roy. Soc. Victoria, 60 (New Series), 123–148.Google Scholar
Edwards, A. B., 1947 b. “The petrology of the Cretaceous greywackes of the Purari valley, Papua”, Proc. Roy. Soc. Victoria, 60 (New Series), 163–171.Google Scholar
Fischer, G., 1933. “Die Petrographie der Grauwacke”, Jahrbuch Preuss. geol. landesanstalt, 54, 320–343.Google Scholar
Henderson, M. K., 1935. “Ordovician submarine disturbances in the Girvan district (Scotland)”, Trans. Roy. Soc. Edin., 58, 487–509.CrossRefGoogle Scholar
Jones, O. T., 1938. “On the evolution of a geosyncline,” Quart. J. Geol. Soc., 94, lx–cx.Google Scholar
Keller, W. O., and Littlefield, R. F., 1950. “Inclusions in the quartz of igneous and metamorphic rocks”, J. Sed. Pet., 20, no. 2, 74–84.Google Scholar
Kennedy, W. Q., and Read, H. H., 1936. “The differentiated dyke of New-mains, Dumfriesshire, and its contact and contamination phenomena”, Quart. J. Geol. Soc., 92, 116–145.CrossRefGoogle Scholar
King, P. B., 1937. “Geology of the Marathon Region, Texas”, U.S. Geol. Surv. Prof. Paper 187.CrossRefGoogle Scholar
King, W. B. R., 1923. “The Upper Ordovician Rocks of the South-Western Berwyn Hills”, Quart. J. Geol. Soc., 79, 478–507.CrossRefGoogle Scholar
Kuenen, Ph. H., 1950. Marine Geology. New York.Google Scholar
Kuenen, Ph. H., 1953. “Graded bedding, with observations on Lower Palæozoic rocks of Britain”, Ver. Konink Nederl. Akad. v. Wet. afd. Natuurk., 20, no. 3, 1–47.Google Scholar
Kuenen, Ph. H., and Menard, H. W., 1952. “Turbidity currents, graded and non-graded deposits”, J. Sed. Pet., 22, 83–95.Google Scholar
Kuenen, Ph. H., and Migliorini, C. I., 1950. “Turbidity currents as a cause of graded bedding”, J. Geol., 58, 91–127.CrossRefGoogle Scholar
Leonhard, K. C., 1823. Charakteristik der Felsarten. Heidelberg.Google Scholar
MacGregor, G. M., 1938. “The evolution of the Criffel-Dalbeattie quartzdiorite: a study of Granitisation”, Geol. Mag., 75, 481–496.CrossRefGoogle Scholar
Mackie, W., 1896. “The sands and sandstones of Eastern Moray”, Trans. Edin. Geol. Soc., 7, 148–172.CrossRefGoogle Scholar
Mackie, W., 1923. “The source of the purple zircons in the sedimentary rocks of Scotland”, Trans. Edin. Geol. Soc., 11, 200–213.Google Scholar
Mackie, W., 1928. “The heavier accessory minerals in the granites of Scotland”, Trans. Edin. Geol. Soc., 12, 22–40.CrossRefGoogle Scholar
Mackie, W., 1929. “Preliminary report on the heavy minerals of the Silurian rocks of Southern Scotland”, Brit. Assoc. Adv. Sci., Glasgow, 1928, p. 556.Google Scholar
Menard, H. W., 1952. “Deep ripple marks in the sea”, J. Sed. Pet., 22, 3–9.Google Scholar
Natland, M. L., and Kuenen, Ph. H., 1951. “Sedimentary history of Ventura Basin, California, and the action of turbidity currents: Turbidity currents and the transportation of coarse sediments to deep water”, Soc. Econ. Palœntologists and Mineralogists Special Publ., No. 2, 76–107.CrossRefGoogle Scholar
Pettijohn, F. J., 1943. “Archean sedimentation”, Bull. Geol. Soc. Amer., 54, 925–972.CrossRefGoogle Scholar
Pettijohn, F. J., 1949. Sedimentary Rocks. New York.Google Scholar
Pringle, I., and Eckford, R. J. A., 1945. “Structures in Silurian greywackes near Innerleithen”, Trans. Edin. Geol. Soc., 14, 5–7.CrossRefGoogle Scholar
Ritchie, M., and Eckford, R. J. A., 1931. “The lavas of Tweeddale and their position in the Caradocian Sequence”, Sum. Prog, for 1930 Mem. Geol. Surv., 46–57.Google Scholar
Ritchie, M., and Eckford, R. J. A., 1935. “The ‘Haggis Rock’ of the Southern Uplands”, Trans. Edin. Geol. Soc., 14, 371–377.Google Scholar
Roth, I., 1887. Allgemeine und Chemische Geologie. Berlin.Google Scholar
Southern Uplands Memoir (Peach, B. N., and Horne, J.), 1889. “The Silurian rocks of Britain. I. Scotland”, Mem. Geol. Surv. U.K.Google Scholar
Tomkeieff, S. I., 1948. “On the derivation of the names ‘quartz’, ‘gneiss’, ‘wacke’ and ‘Kramenzelkalk’”, Geol. Rdsch., 36, 98–99.CrossRefGoogle Scholar
Trask, P. D. et al. , 1939. Recent Marine Sediments, A Symposium. Tulsa.CrossRefGoogle Scholar
Tyrrell, G. W., 1933. “Greenstones and greywackes”, C.R. Réunion Int. pour l'Étude du Pre-Cambrien, 1931, 24–26.Google Scholar
Williams, H., and Bulman, O. M. B., 1931. “The geology of the Dolwyddelan Syncline (North Wales)”, Quart. J. Geol. Soc., 87, 425–456.CrossRefGoogle Scholar
Woodland, A. W., 1938. “Petrological studies in the Harlech Grit Series of Merionethshire. II. The petrography and petrology of some of the grits”, Geol. Mag., 75, 440–454. III. “The development of pyrite in the grits and mudstones”, Geol. Mag., 75, 529–539.CrossRefGoogle Scholar