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Measurement and distribution of zircons in some granitic rocks of magmatic origin

Published online by Cambridge University Press:  14 March 2018

Leonard H. Larsen  and
Arie Poldervaart
Leonard H. Larsen
Affiliation:
Dept. of Geology and Geography, University of Cincinnati, Ohio, U.S.A.
Arie Poldervaart
Affiliation:
Dept. of Geology, Columbia University, New York, U.S.A.
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Summary

Morphological characters of zircons in concentrates have been studied by measurement of length along the c-axis and breadth along the a1- or a2-axis of 200 doubly terminated crystals for each sample. The sample is represented graphically by a line fitted mathematically to a scatter plot of the measurements. This line, the reduced major axis, is visualized as a growth trend, and samples are described and compared statistically.

From a careful study of zircons in a tonalite it is concluded that zircon crystallized over a short range before crystallization of the main constituent minerals.

The distribution of zircon in a batholith of magmatic origin has also been studied. The batholith grades from a core of granodiorite to a mantle of tonalite, but the zircons are uniform throughout. Small bodies of granodiorite and quartz monzonite have sharp contacts against the main batholithic rocks, and zircon samples from these intrusives differ from one another and from those of the batholith. It is concluded that the batholith represents a single intrusion which differentiated after emplacement, and that the later intrusives each crystallized under different conditions.

Type
Research Article
Information
Mineralogical magazine and journal of the Mineralogical Society , Volume 31 , Issue 238 , September 1957 , pp. 544 - 564
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1957

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References

page 544 note 1 Amer. Min., 1937, vol. 22, p. 73 [M.A. 7-188].

page 544 note 2 Geologica, 1951, Rcihe 9, 114 pp. [M.A. 12-32].

page 544 note 3 Amer. Jour. Sci., 1956, vol. 254, p. 521.

page 545 note 1 A. Poldervaart, loc. cit., p. 546.

page 545 note 2 W. Eitel, The Physical Chemistry of the Silicates, 1954, Chicago Univ. Press, p. 569.

page 546 note 1 For example, E. S.Larsen et al., Amer. Min., 1938, vol. 23, p. 255 [M.A. 7-178].

page 546 note 2 N. Holgate. Jour. Geol., Chicago, 1954, vol. 62, p. 439 [M.A. 12-537].

page 546 note 3 Trans. Geol. Soc. South Africa, 1951, vol. 54, Annex, 27 pp. ; Geol. Soc. Amer., Spec. Paper 62, 1955, p. 409.

page 546 note 4 Geol. Mag., 1939, vol. 76, p. 351.

page 546 note 5 J. Imbrie, Bull. Amer. Mus. Nat. Hist., 1956, vol. 108, art. 2, p. 230.

page 547 note 1 Biometrika, 1950, vo]. 37, p. 30.

page 547 note 2 J. Imbrie, loc. cit., p. 244.

page 548 note 1 More precisely, sx is the standard deviation (in x) of the sample, as distinct from the unknown (alpha)x, the standard deviation (in x) of the total population, and σx, the best estimate of σx; σx = sx {√/ N /(N—l)} .

page 548 note 2 Loc. cit., p. 241.

page 549 note 1 Prof. Howard Levene, Columbia University, 1956, personal communication.

page 549 note 2 Values of z are tabulated in most statistical texts. If N is large (e.g. 200) z may be regarded as equivalent to t, and t tables may be used instead.

page 549 note 3 J. Imbrie, loc. cir., p. 237.

page 550 note 1 Amer. Jour. Sci., 1955, vol. 253, p. 435.

page 550 note 2 Bull. Geol. Soc. Amer., 1950, vol. 61, p. 643.

page 553 note 1 Amer. Min., 1925, vol. 10, p. 187.

page 554 note 1 A. Poldervaart, Amer. Jour. Sci., 1956, vol. 254, p. 529.

page 555 note 1 Loc. cit., p. 547.

page 559 note 1 Bull. Geol. Soc. Amer., 1957, vol. 68, p. 181.

page 561 note 1 Geol. Soe. Amer., Spec. Paper 62, 1955, 10. 489.

page 562 note 1 Trans. Geol. Soc. South Africa, 1951, vol. 54, Annex; and Geol. Soe. Amer., Spec. Paper 62, 1955, p. 409.

page 563 note 1 J. Imbrie, loc. cit., p. 223.

page 563 note 2 A. Poldervaart, loc. cit., p. 522.

page 563 note 3 Loc. cit., 1951, p. 21.

page 563 note 4 Jour. Geol. Soc. Japan, 1954, vol. 60, p. 517.

page 563 note 5 F. D. Eckelmann and A. Poldervaart, Bull. Geol. Soc. Amer., 1955, vol. 66, p. 947.