Sample Book Review
The following is a sample of a well-written book review.
Origins of Igneous Layering
Ian Parsons (Ed.), D. Reidel, Hingham, Mass, xxii + 666 pp., ISBN 0-000-0000, 1987, $124.
Anyone who has ever seen a photo of a layered intrusion, let alone visited one first hand, or even seen a thin section from one, cannot help but be impressed by the stunning record of crystal growth and deposition. Such bodies stand as majestic monuments of undeniable evidence that intricate magmatic processes exist, processes that couple crystallization, convection, and crystal sorting to form rocks so highly ordered and beautiful that they are a wonder to behold. These are the altars to which petrologists must carry their conceived petrologic processes for approval.
Although significant in number, the best layered intrusions seem to be found almost always in remote places. Their names, Bushveld, Muskox, Kiglapait, Stillwater, Duke Island, Skaergaard, Rhum, ring through igneous petrology almost as historic military battles (Saratoga, Antietam, Bull Run, Manassas, Gettysburg) do through American history. People who have worked on such bodies are almost folk heroes: Wager, Deer, Brown, Jackson, Hess, Irvine, McBirney, Morse; these names are petrological household words. Yet with all this fanfare and reverence, layered intrusions are nearly thought of as period pieces, extreme examples of what can happen, but not generally what does. This is now all changing with the increasing realization that these bodies are perhaps highly representative of all magmatic bodies. They are simply more dynamically complete, containing more of the full range of interactions, and of course, exposing a more complete record. They are one end of a spectrum containing lava flows, lava lakes, large sills, plutons, and layered intrusions. This book uniquely covers this range with an abundance of first-hand field observations and a good dose of process conceptualization, magma physics, and crystal growth kinetics.
This is a collection of 20 full-length papers presented at the NATO Advanced Research Workshop on Origins of Igneous Layering held during August 1986 at Narsarsuaq in South Greenland. Twenty (lucky) invited experts were ferried about by boat and helicopter and shown some of the world’s most extraordinary and best exposed layered igneous rocks. One can well imagine the level of daily discussion when the previous day’s presentations were then brought to the final court of appeal, the rocks themselves.
The book itself is of normal size, shape, and heft. It is well bound and has the usual cover design of books in this series. The table of contents is nicely detailed, and the page numbers and running headers are in their proper places. The text is all camera ready, almost completely free of typos, well organized, and well printed; there is a satisfactory subject index. The book can be roughly separated into two parts: the first consists of 11 field-based reports arranged broadly “in order of decreasing fractionation of the dominant rock types”; the second part is a series of conceptual, theoretical, and experimental papers treating layer formation, texture evolution, and crystallization kinetics. Sandwiched between these two parts, which actually blend nicely together, is a collection of 30 quarter-page photographs of field examples of layering contributed by the workshop members as a whole. Following the second part are two appendices by T. N. Irvine on nomenclature for layered rocks and a list of possible processes leading to the formation of layered rocks.
Three things set this book apart from most others in this vein: each paper is to the point, worth reading, and even worth studying; the abundant photographs are excellent, not only in choice but in reproduction, continually drawing one into the text; and a strong interawareness of field, experiment, and theory appears in nearly every paper. These features steadily bring the issue of concern to the surface, that is, to what extent can layered rocks be adequately explained by purely sedimentological processes and by purely chemical, postdepositional processes. The problem is the same as for salt deposits. Namely, how is it possible to make a monomineralic layer? Is it by fractionation of a liquid, as in double diffusive convection, by sedimentation, adcumulus growth, and compaction, or by total textural requilibration in response to the interaction of early crystals and a chemically evolving liquid. There is seemingly good field and theoretical evidence all around. These works are so well focused that they quantitatively bear on one another rather than, as is more common, passing each other unnoticed in rhetorical darkness.
This book is a landmark publication, literally reeking of wonderful field observations and a host of well thought out and well presented ideas. Every serious igneous petrologist will want this book. It is simply excellent. Parsons has done a splendid job. At the same time it is a tragedy that such an exorbitant price of $124 will make this superb book unavailable to most students of the subject.
–Bruce Marsh, Department of Earth and Planetary Sciences, Johns Hopkins University, Baltimore, Md.
