BOOK REVIEW — Atlas offers aid for young core logger

.BReviewed By James Whyte

Atlas of Alteration

By Anne Thompson and John Thompson, editors

$55

Special Publication No. 6 of the Mineral Deposits Division,

Geological Association of Canada

It is a time-honored tradition in the mineral industry to subject newly graduated geologists to an initiation gently termed “dogging a drill.” The fresh-faced youngster is placed in a small enclosure, with little light and no comforts save a badly chipped ashtray, and given box upon wooden box of drill core to describe in accordance with geological Scripture.

It is not long before the pile of boxes outside the door is a ladder from earth to Heaven, while the shivering neophyte is still puzzling over the first box. The recruit has been stumped by the strange appearance of the minerals, which bear little or no resemblance to the pictures of pristine crystals in the mineralogical texts; and the core shack rings with newly-learned cuss words, aimed at the oily tormentors in coveralls who bring the boxes, and at all the instructors that never mentioned the value of learning what alteration minerals look like.

Now into the breach step Anne and John Thompson, whose Atlas of Alteration, published by the Mineral Deposits Division of the Geological Association of Canada, was conceived to fill this poor creature’s need. With the assistance of a long list of contributors, the editors document more than 40 common, and less common, alteration minerals and mineral mixtures, providing practical descriptions designed for confident identification, insight into the geological and geochemical significance of the mineralogy, and — best of all — pictures of the real thing in outcrops, cores, hand specimens and thin sections. A table of optical properties, at the back of the book, may enjoy the distinction of being the only table of optical properties that actually starts with crystal form and growth habit — a far more useful diagnostic tool than the quantitative optical properties by which conventional textbooks set such store.

Add an introduction that offers the student of alteration a checklist approach to interpreting alteration mineralogy, and a simple table of common alteration types that probably offers the best quick study available in the literature, and the product is a valuable reference for the troubled young geologist (and for many a troubled old one).

The Atlas of Alteration is a useful and detailed guide to alteration mineralogy, and will be as handy in the core shack as it is in the laboratory. It is also a terrible disservice to the industry, which will have to spend much time and trouble devising a new initiation ritual.