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On the genetic relationship and clasaification of Meteorites1

Published online by Cambridge University Press:  14 March 2018

G. T. Prior*
Affiliation:
Mineral Department of the British Museum

Extract

In a previous paper attention was drawn to the close similarity in mineral and chemical composition of chondritic meteoric stones. In the case of about forty chondrites it was shown that, apart from variations in the amount of nickel-iron, not only are the constituent minerals present in very similar amounts, but their chemical compositions vary to no very great extent. In that paper sufficient importance was not attached to the variations in the amount of nickel-iron.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1916

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Footnotes

1

Communicated by permission of the Trustees of the British museum.

References

page 26 note 2 Prior, G. T., 'On the remarkable similarity in chemical and mineral composition of ehondritic meteoric stones.' Mineralogical Magazine, 1913, vol. xvii, pp. 3338 CrossRefGoogle Scholar.

page 28 note 1 Cohen, E., Ann. South African Museum, 1906, vol. v, p. 1 Google Scholar.

page 28 note 2 Merrill, G. P., Proc. U. S. Nat. Museum, 1915, vol. xlix, p. 109 CrossRefGoogle Scholar.

page 28 note 3 W. Wahl, 'Die Enstatitaugite.' Min. Pert. Mitt., 1907, vol. xxvi, p. 1.

page 28 note 4 In the following lists are included, besides other more recent analyses, all those quoted by O. C. Farrington in 'Analyses of Stone Mctcorites'. Field Museum of Natural History, 1911, Publication 151, Geol. Series, vol. iii, No. 9. The original references have been consulted, for in Farrington's list it is not always possible to determine whether the iron for the sulphur is to be taken from Fe or FeO. Where the chemical composition of the olivine aJad bronzite have been determined, the ratio of MgO to FeO has been calculated from them. The numbers in brackets placed in some eases after this ratio is the ratio for the insoluble alone, for, when the separation of the metallic iron has been imperfect, more reliance can be placed upon this ratio than upon that for the soluble.

page 29 note 1 Doubtful ; if correct, these analyses, in which the ratio MgO : FeO is so high, suggest a passage to Group 1. In the case of Klein-Wenden, as in some others of his analyses, Rammelsberg appears to have rather over-corrected for the NiO in the unattracted part.

page 29 note 2 The numbers given depend on Abich's statement that the stone contains over 10 per cent. of nickel-iron, instead of the much lower amount indicated by the bulk-analysis.

page 30 note 1 Doubtful, as it contains nearly 11 per cent. of Fe2O3.

page 31 note 1 These possibly belong to Group 3, for the MgO : FeO ratio for the insoluble is as high as 4½ and the specific gravities of the stones are all over 3·5, which suggests a somewhat higher percentage of nickel-iron than that given in the analyses.

page 31 note 2 Doubtful, for the soluble contains nearly 3 per cent. and the insoluble nearly 2 per cent. of NiO, indicating that the separation by means of iodine of the metal was imperfect.

page 31 note 3 Doubtful, as the analysis was incomplete, the nickel-iron not being determined. It possibly belongs to Group 3.

page 31 note 4 Doubtful, as it is supposed to contain 10 per cent. of limonite ; the ratio for the bronzite is so high owing to the large amount of FeO required for the extraordinarily high percentage of chromite (nearly 10 per cent.).

page 31 note 5 Doubtful: on Crook's analyses, see G. Tsehermak, Sitzber. Wien. Akad., 1872, vol. lxv, p. 134.

page 31 note 6 Doubtful, as it contains nearly 8 per cent. of Fe2O3.

page 31 note 7 Doubtful, owing to high MgO :FeO ratio for the insoluble and the presence of nearly 8 per cent. of NiO in the soluble. It possibly belongs to Group 2, like Allegan, which belongs to the same class (Cco), as d~es also Warrenton, which so closely resembles Ornans in external appearance.

page 31 note 8 The omission of some of the most detailed and accurate analyses of meteoric stones we possess, such as those of Zomba and Makariwa by L. Fletcher, was due probably to the results being given as analy~s of the individual constituents and not as bulk-analyses.

page 33 note 1 Wadsworth's calculation of the bulk-analysis, as quoted by Farrington, is not in agreement with the details of the analyses.

page 36 note 1 H. Michel, 'Plagiokiase der Meteoriten.' Min. Petr. Mitt., 1913, vol. xxxii, p. 170.

page 38 note 1 An alternative plan would be to retain the name Chladnite for BishopviUe as a stone consisting mainly of pure enstatite without diopside, and to revive Tschermak's name of diogenite for the bronzito stones, Shalka, Manegaum, and Ibbenbühren.

page 38 note 2 Wahl, W., Min. Petr. Mitt., 1907, vol. xxvi, p. 90 Google Scholar.

page 38 note 3 Sir L. Fletcher, 'An Introduction to the Study of Meteorites' (British Museum Guide-Book), eleventh edit., 1914, p. 50.

page 39 note 1 Nordenskiöld, A. E., Geol. Foren. Forh. Stockholm, 1878, vol. iv, p. 56 Google Scholar.

page 39 note 2 Wahl, W., 'Beiträtge zur Chemic tier Meteoriten.' Zeit. Anorg. Chemie, 1910, vol. lxix, p. 67 Google Scholar.

page 39 note 3 Part of the Ca and Cr are in the form of sulphides, oldhamite and daubrcolite.

page 39 note 4 This fact, which has given rise to much comment, has been explained by Wahl (l. c. p. 70) as due to the lower heat of production of oxide of nickel as compared with that of oxide of iron.

page 40 note 1 Borgströ, L. H., 'Der Moteorit von St. Michel.' Bull. Comm. Geol. Finlande, 1912, No. 34, p. 38 Google Scholar.

page 40 note 2 Sir Ball, Robert, 'Speculations on the Source of Meteorites.' Nature, 1879, vol. xix, p. 493 CrossRefGoogle Scholar.

page 41 note 1 R. A. Daly, 'Igneous Rocks and their Origin.' 1914.

page 41 note 2 Bowen, N. L., 'The later stages of the evolution of the Igneous Rocks.' Journ. Geol., 1915, vol. xxiii, No. 8, Supp.Google Scholar