Kimberlites, Orangeites, Lamproites, Melilitites, and Minettes: A PETROGRAPHIC ATLAS by Roger Mitchell

Roger Mitchell, internationally recognized petrologist and one of the world authorities on diamond-bearing rocks, has recently produced his latest book, Kimberlites, Orangeites, Lamproites, Melilitites, and Minettes: A Petrographic Atlas.

Following closely on the heels of his well-received trilogy: Kimberlites; Mineralogy, Geochemistry and Petrology; Petrology of Lamproites; and Kimberlites, Orangeites, and Related Rocks; this publication has received enthusiastic reviews from petrologists who are themselves internationally recognized in their respective fields.

Prof. W. S. MacKenzie has published several similar petrographic atlases and thus is eminently qualified to appraise Mitchell's work, as is Barbara Scott Smith, a consultant geologist who is a world recognized authority on the petrology of diamond-bearing rocks. The following excerpts from their reviews speak for themselves. Please read these reviews and decide for yourself the value to you of adding this volume to your library.

In addition to providing a complement to MacKenzie's atlases, covering as it does, rock types not dealt with by that series, this book provides outstanding petrographic images of some rare and economically important rocks. It is thus an invaluable reference work - not only for anyone working in the diamond exploration industry, but also those involved in teaching and research.

W. S. MacKenzie, Mineralogical Magazine, 1998, 62, 727-729
This book consists mainly of very high quality colour photographs of thin sections of some alkaline rocks viewed under the microscope, about 50 of them being back -scattered electron images with false colouring. The majority are of standard thin sections photographed in plane polarized light or between crossed polars. The plates in the book are 100mm x 150mm in size and the magnifications at which most of the plates are reproduced are x60 or x152. The electron microscope images are of higher magnification and a few of the optical photomicrographs were taken at lower magnification in order to show a larger field of view.

The author tell us in the Preface that the principle objective of the work is to provide a guide to the petrographic character of the commoner textures and assemblages of minerals found in a group of alkaline rocks of interest to both academic petrologists and exploration geologists. The economic interest of course is that the first three rock types are primary sources of diamond but since diamonds are considered to be xenocrysts, further comment on their occurrence is not relevant in this work.

The atlas is a very useful companion to many of the recent publications of Roger Mitchell, particularly three text-books, on these unique and fascinating rocks and their mineralogy. In this respect it could be considered as directed to a very specialized readership, but I believe it may have an equally useful function as an aid to teachers of petrography and petrologists in general. I do not know how many geology departments in the U.K., or that matter in any other country, have sufficiently good rock collections to illustrate more than one or two examples of even kimberlites or melilitites. It is a great pleasure for me personally to see thin sections of rocks from well known localities, of which one has heard but never seen, and from localities which are entirely new to me.

Of the 400 illustrations, 188 are of kimberlites, 62 orangeites, 84 lamproites and 16 minettes. The photographs are the best reproductions of photomicrographs which I have seen anywhere and they were reproduced from 35mm transparencies. The magnification chosen by Mitchell is just over four times that of his transparencies and I believe that his choice of lOO x 150 mm prints is the main reason for the considerable impact of this beautiful collection of photographs; it goes without saying that the original transparencies has sharp focus and uniform lighting.

This reviewer is not familiar with the prices of books in Canada or the U.S.A. at the present time but for a publication with so many excellent colour photographs it seems a very reasonable price.