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?]
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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![The Distribution and Significance of Deviations from the Nonnal Order of Crystallization, also the Distribution and Significance of Micropegmatite in Granites, as illustrated by the Granites of the North of Scotland. By William Mackie, M.A., M.D., &c. (MS. received I7th January, 1908. Read I8th November, 1908.) The' results embodied in this, paper were worked out with the aid of a grant and the loan of a ]jetrological microscope from the Carnegie Trustees. These I gratefully acknowledge. I have further to acknowledge an additional grant in aid of the printing and illustration of the .same. W. M. In some of my previous investigations, which entailed the micro- scopic examination of a considerable number of the granites of the North of Scotland, it became evident that deviations from the normal order of crystallization existed in almost every rock- slice I examined, while the occurrence of areas of micro- pegmatite in the same rocks appeared to be far more frequent than the ordinary descriptions of such rocks would indicate. The present research has accordingly been undertaken with the view of testing these general impressions; to obtain data from which some generalization may be made as to the order of crystallization, and as to the occurrence and distribution of micropegmatite; and further, if possible, to arrive at some definite conclusions as to the origin and causation of the ob- served phenomena. In this connection specimens from most of the larger granite masses of the North of Scotland, that is from north of the Grampian range, have been subjected to microscopic examination. The rocks of the Grampian range itself are pro- bably insufficiently represented in the following lists ; but all the rest of the area is, I think, very fairly represented. Diorites in a number of instances have been included, while a few rocks of the dyke and effusive acid type have also been included. Fragments of granite occurring as pebbles in the Old Ked Sand- stones of the North of Scotland as likely to indicate possible variations in the granite masses in a vertical direction in regard to the particular points at issue have also in a number of instances been examined. Purely basic rocks have not been included except in one or two instances, where they have been found to show micropegmatite existing or developed under exceptional conditions. In the accompanying tables, the granites have been divided into four classes, according to their general basicity or acidity, foliation, etc. Such rocks as diorites, felsites, etc., not strictly classifiable as granites, have been classified with the type of rock to which they are most closely related. To make these tables](https://iiif.wellcomecollection.org/image/b2242782x_0005.jp2/full/800%2C/0/default.jpg)
