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A magnesian chamosite from the Wenlock Limestone of Wickwar, Gloucestershire

Published online by Cambridge University Press:  14 March 2018

F. A. Bannister  and
W. F. Whittard
F. A. Bannister
Affiliation:
Mineral Department, British Museum
W. F. Whittard
Affiliation:
University of Bristol
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Extract

The Little Avon river rises on the scarp slope of the Cotswolds near Hawkesbury, 14 miles north-east of Bristol, and flows in a westerly direction over Mesozoic strata, until half a mile south-east of Wickwar it cuts through the Triassic mantle and exposes to view three inliers of Wenlock Limestone (Whittard & Smith, 1944, p. 65 and map). The West Gloucestershire Water Company was interested in the valley as a possible site for an impounded reservoir, and as part of a preliminary survey a trial-shaft was sunk into the Wenlock Limestone of the southernmost inlier situated near Sturt Bridge. The shaft penetrated 28 feet of dolomitized siltstones and crinoidal limestones, and at a depth of 4 feet it entered a band of calcareous chamositic siltstone averaging 9 inches in thickness. The shaft had been completed and the sides boarded before we heard it had been sunk; the hand-specimens were therefore obtained from the tip-heaps, but there is no doubt that all the material originated from the same horizon.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 27 , Issue 190 , September 1945 , pp. 99 - 111
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1945

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References

Deans, (T.), 1934. The spherulitic ironstones of west Yorkshire. Geol. Mag., vol. 71, pp. 49–65. [M.A. 6–28.]Google Scholar
Dixon, (B. E.), 1930. Summary of progress for 1929. Mem. Geol. Surv. Great Britain, pt. i, pp. 98–99.Google Scholar
Engelhardt, (W. von), 1942. Die Strukturen von Thuringit, Bavalit und Chamosit und ihre Stellung in der Chloritgruppe. Zeits. Krist., vol. 104, pp. 142–159. [M.A. 8–291.]Google Scholar
Ennos, (F. R.) & Sutcliffe, (R.), 1925. On the estimation of the chlorite in sedimentary rocks by extraction with dilute hydrochloric acid. Appendix to Hallimond (1925), pp. 115–120.Google Scholar
Gruner, (J. W.), 1944. The kaolinite structure of amesite, (OH)3(Mg,Fe)4Al2(Si2Al2)O10, and additional data on chlorites. Amer. Min., vol. 29, pp. 422–430.Google Scholar
Hallimond, (A. F.), 1925. Iron ores: bedded ores of England and Wales. Petrography and chemistry. Mem. Geol. Surv. Great Britain, Special Reports, Mineral Resources, vol. 29, pp. 1–139.Google Scholar
Hallimond, (A. F.) 1939. On the relation of chamosite and daphnite to the chlorite group, with chemical analyses by C. O. Harvey and X-ray measurements by F. A. Bannister. Min. Mag., vol. 25, pp. 441–464.Google Scholar
Hawes, (G. W.), 1875. Contributions from the Sheffield Laboratory of Yale College, No. XXXIII. On diabantite, a chlorite occurring in the trap of the Connecticut valley. Amer. Journ. Sci., ser. 3, vol. 9, pp. 454–457.CrossRefGoogle Scholar
Hayes, (A. O.), 1915. Wabana iron ore of Newfoundland. Geol. Surv. Canada, Mem. 78, no. 66, pp. 1–163.Google Scholar
Holzner, (J.), 1938. Eisenchlorite aus dem Lahngebiet; chemische Formel und Valenz-ausgleich bei den Eisenchloriten. Neues Jahrbuch Min., Abt. A, vol. 73, pp. 389–418. [M.A. 7–408.]Google Scholar
Jung, (H.) & Köhler, (E.), 1930. Untersuchungen über den Thuringit von Schmiedefeld in Thüringen. Chem. Erde, vol. 5, pp, 182–200. [M.A. 4–334.]Google Scholar
Jung, (H.), 1931. Untersuchungen über den Chamosit von Schmiedefeld i. Thür. Ibid., vol. 6, pp. 275–306. [M.A. 5–40.]Google Scholar
Knight, (R. G.), 1937. Mineral residues of some British limestones. Thesis submitted for diploma, Imperial College of Science and Technology, London.Google Scholar
McMurchy, (R. C.), 1934. The crystal structure of the chlorite minerals. Zeits. Krist., vol. 88, pp. 420–432. [M.A. 6–45.]Google Scholar
Oakley, (K. P.), 1934. Phosphatic calculi in Silurian polyzoa. Proc. Roy. Soc. London, Ser. B, vol. 116, pp. 296–314.Google Scholar
Pauling, (L.), 1930. The structure of the micas and related minerals. Proc. Nat. Acad. Sci. U.S.A., vol. 16, pp. 123–129. [M.A. 4–368.]CrossRefGoogle ScholarPubMed
Pulfrey, (W.), 1933. The iron-ore oolites and pisolites of North Wales. Quart. Journ. Geol. Soc. London, vol. 89, pp. 401–427.Google Scholar
Rastall, (R. H.) & Hemingway, (J. E.), 1940. The Yorkshire Dogger. I. The coastal region. Geol. Mag., vol. 77, pp. 257–275.Google Scholar
Shannon, (E. V.), 1920. Analyses and optical properties of amesite and corundophilite from Chester, Massachusetts, and of chromium-bearing chlorites from California and Wyoming. Proc. U.S. Nat. Mus., vol. 58, pp. 371–379. [M.A. 1–214.]Google Scholar
Shannon, (E. V.) & Wherry, (E. T.), 1922. Notes on white chlorites. Journ. Washington Acad. Sci., vol. 12, pp: 239–241. [M.A. 2–189.]Google Scholar
Smith, (W. C.), 1924. On a compact chlorite from Bernstein, Austria. Min. Mag., vol. 20, pp. 241–247.Google Scholar
Sollas, (W. J.), 1879. On the Silurian district of Rhymney and Pen-y-lan, Cardiff. Quart. Journ. Geol. Soc. London, vol. 35, pp. 475–507.Google Scholar
Tschermak, (G.), 1891. Die Chlorit Gruppe. Sitz. ber. Akad. Wiss. Wien, vol. 100, pp. 29–107.Google Scholar
Whittard, (W. F.) & Smith, (S.), 1944. Unrecorded inliers of Silurian rocks, near Wickwar Gloucestershire, with notes on the occurrence of a stromatolite. Geol. Mag., vol. 81, pp. 65–76.CrossRefGoogle Scholar
Winchell, (A. N.), 1936. A third study of chlorite. Amer. Min., vol. 21, pp. 642–651. [M.A. 6–532.]Google Scholar