The distribution & significance of deviations from the normal order of crystallization : also the distribution & significance of micropegmatite in granites, as illustrated by the granites of the north of Scotland / by William Mackie.

  • Mackie, William
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: The distribution & significance of deviations from the normal order of crystallization : also the distribution & significance of micropegmatite in granites, as illustrated by the granites of the north of Scotland / by William Mackie. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    General summary of rocks examined :— Rocks. Slides. Micropegmatite. Basic or Hornblendic . 23 49 Ai, B„, Cm.p.j Cm.g., None„ 23 Acid (Biotite) . . . . 47 96 Ai„ B.,1, Cm.p.„, Cm.g.n, None^ Acid (double mica) 14 47 23 Bi^ 14 Acid Foliated . . . . 6 14 Ag, B„ 6 Totals 90 182 Ag,, B«2, Crn.p.,,. Cm.g.n, Noneig 90 < Jeneralization as to occuiTence of micropegraatite :— Micropeginatite of the A type seen in 2.3’3% of rocks examined. ,y » B »> >> 68'8% ,, » » » C ,, ,, I3‘3% ,, I) Microgranitic areas 12'2% Absence of any form of micropegmatite 17’7% Occurrence of the diflFerent forms of micropegmatite in the different kinds of rocks. Hornblendic rooks (23) „ granites (9) Biotite rocks (47) granites (36) Double mica granites (14) Foliated granites (6) For graphic representation of above see PI. XXV. A B m.p C m.g. Absent 4% 48% 4% 9% 48% 0% .56% 11% 0% 33% 36% 66% 23% 19% 10-6o/„ 47% 80% 5-5% 5-5% 13% 0% 100% . . . • • • 50% 100% . - Oeneralizaiioti as to abnormalities in the order of crystallization, stated as percentages of rocks examined :— Class of Rocks. Horn- Blolite. Sphene. I’lagio- Ortho- blende. clase. clase. Horn- j'Quartz, seen in 52% 30% 26% 13% 17% blcndicl Orthoclase ,, . . 34-7 22% 13% 9% . , roc ks (^Plagioclase „ 34-7% 17% 22% See Fig. 1, Plate XXVI. Biotite (Quartz, seen in rooks -! Orthoclase ,, (Plagioclase ,, 30% 4% 23% 37-5% , , 10% 2% 6% 14-5% 2% - - See Fig. 2, Plate XXVI. Double [ Quartz .... , , 28% , 28% 43% mica -! Orthoclase rocks (Plagioclase 0% 21% 7% See Fig. 3, Plate XXVI. Over all, the aberrations of quartz from its normal order in the scheme of crystallization are much in excess of those of any of the other minerals, while those of plagioclase are in excess of those of •orthoclase. See Fig. 4, Plate XXVI.
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