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Examples of twinning and parallel growth in zircons from some Precambrian granites and gneisses

Published online by Cambridge University Press:  05 July 2018

J. Jocelyn
Affiliation:
Scottish Universities Research and Reactor Centre, East Kilbride, Scotland
R. T. Pidgeon
Affiliation:
Scottish Universities Research and Reactor Centre, East Kilbride, Scotland

Summary

Growth twins, parallel growths, and necked crystals are described from zircon populations from granitic gneisses from the Precambrian of SW. Greenland. From observations of the distribution of internal growth zones it is concluded that whereas twinning takes place early in the growth history of elbow twins it can occur at any time during crystallization of the zircon. Parallel growth is attributed to a process of synneusis or attachment of zircons that have initially undergone separate growth histories. This implies that viscosity conditions of the rocks were low enough to permit the movement and collision of growing zircon crystals. The common occurrence of zircons with central constrictions, sometimes superimposed on transverse fractures, in zircon suites from the granitic gneisses is explained in terms of late-stage chemical corrosion accompanied by brittle fracturing.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1974

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References

Berry, (L. G.) and Mason, (B.), 1959. Mineralogy. San Francisco (Freeman).Google Scholar
Berzina, (A. P.) and Sotnikov, (V. I.), , 1963. Doklady Akademii hank SSSR, 150, 118-20 (English translation of ).Google Scholar
Carstens, (H.), 1968. Amer. Min., 53, 342.Google Scholar
Caruba, (R.) and Turco, (G.), 197I. Bull. Soc. franc. Min. Crist., 94, 427–36.Google Scholar
Chowdhary, (P. K.), 197I. GeoL Mug., 108,255-62.Google Scholar
Dalziel, (I. W. D.), 1963. Trans. Edin. Geol. Soc., 19, 349–62.CrossRefGoogle Scholar
Donnelly, (T. W.), 1967. Amer. Min., 52,I-12.Google Scholar
Frondel, (C.), 1940. Ibid. 25,69-87.CrossRefGoogle Scholar
Gaubert, (P.), 1896. Bull. Soc. franr Min., 19, 43 14.Google Scholar
Groves, (A. W.), 1927. Geol. Mag., 44,457-73.Google Scholar
Harris, (R. L. Jr.), 1959. Bull. Geol. Soc. Amer., 70, I 185216.CrossRefGoogle Scholar
Hopgood, (A. M.), in press. Rapp. Gronlands geoL Unders. Google Scholar
Hintze, (C.), 1915. Handb. Min., 1, Abt. 2. pp. 1212-2674 Leipzig (Veit).Google Scholar
Ingham, (F. T.), 1929. Proc. Geol. Assoc., 40,1-17.CrossRefGoogle Scholar
Kalsbeek, (F.) and Zwart, (H. J.), 1967. Geologie Mijnb., 46e,457-66.Google Scholar
Kostov, (l.), 1968. Mineralogy. Edinburgh (Oliver and Boyd) (author's translation ed. Embrey, P. G. and Phemister, J.).Google Scholar
Kunz, (G. F.), 1892. Gems and Precious Stones of North America (2nd edn, reprinted 1968, Dover Publications, New York).Google Scholar
Larsen, (L. H.), 1955. Bull. Geol. Soc. Amer., 66,1588.Google Scholar
Ozhogin, (V. A.) , 1968. Doklady Akademii nauk SSSR,, 182, 159-62. (English translation of CCCP).Google Scholar
Pidgeon, (R. T.) and Aftalion, (M.), 1972. Earth Planet. Sci. Letters,, 17,269-74.CrossRefGoogle Scholar
Poldervaart, (A.) and Eckelmann, (F, D.), 1955. Bull. Geol. Soc. Amer., 66,947-8.Google Scholar
Poldervaart, (A.) and YON BACKSTR()M, (J. W.), 1950. Trans. Geol. Soc. S. Africa,, 52,433-95.Google Scholar
Pupin, (J. P.) and Turco, (G.), 1972. Compt. Rend. Acad. Sci. Paris (series D), 274,2t21-41.Google Scholar
Schaskolsky, (M.) and Schubnikov, (A.), 1933. Zeits. Krist., 85,1-16.Google Scholar
Schirlowski, (M. O. G.), 1963. Neues Jahrb. Mitt., Abh. 100, 145-63.Google Scholar
Silver, (L, T.), 1969. In Origin of Anorthosite and related rocks, Isachsen, (Y. W.), editor, New York State Museum and Science Service Memoir 18.Google Scholar
Van Breemen, (O.), Allaart, (J.), and Aftalion, (M.), in press. Geol. Unders. Rapp. Gronlands. Google Scholar
Vance, (J. A.), 1969. Contr. Miner. Petrol., 24,7-29.CrossRefGoogle Scholar
Verspyck, (G. W.), 1961, Geologie Mijnb., 40,58-70.Google Scholar
Viola, (C.), 1902. Zeits. Krist., 36, 234–44.Google Scholar
Vogt, (J. H. L.), 1921. Journ. GeoL, 29, 318–50.CrossRefGoogle Scholar