D. R. Lentz (ed.)(1998) Mineralized intrusion-related skarn systems.|
Mineralogical Association of Canada Short Course Volume 26, 664 pp, Canadian $60
It has now been almost twenty years since publication of a number of classic modern compilations on the geology of skarn deposts by weokers such as Einaudi, Burt, etc. This volume of papers from a joint Geological and Mineralogical Associations of Canada course represents the most important and complete collection of articles on this mineral deposit type since the early 1980's. The chapters in this volume include results of both experimental and field studies of skarn systems. In the case of some skarn types that have been relatively uneconomic in present times, such as tin and tungsten skarns, there may not have been an abundance of detailed studies of individual deposits during the last twenty years. Nevertheless, as noted in the chapter by Newberry, significant advances in the general understanding of magmatic hyydrothermal systems have still allowed for important new insights into various skarn systems. These are weel-documented throughout this volume. In particular, advances in regional tectonics and in fluid evolution during magmatic crystallization have been critical in the development of more comprehensive models of metalliferous skarn formation.
The first half of this volume contains chapters on experimental studies of skarn devlopment and calc-solicate geochemistry. The experimental work includes discussions of phase and aqueous equilibria for determination of physiochemical variables of skarn formation, ionic exchange vectors for studying the composition of calc-silicate assemblages, hydrodynamics of fluid-rock interaction, and stable isotope systematics in skarn environments. Other contributions focus on the geochemistry of pyroxenes and scapolite-group minerals from various skarn types.
The latter part of the volume is focused on specific types of skarn deposits. Chapters include review articules by recognized experts on the geology of deposits classified into tungsten/tin, polymetallic, gold, and rare earth element-U-Th-rich skarn and replacement deposits. Well-studied examples of specific, economically-important skarn deposits are also included. These include descriptions of the Gunung Bijih Tumur Cu-Au skarn, Indonesia; the Copper Canyon gold skarn of the Battle Mountain district, Nevada, USA; gold, copper, and tungsten skarns in British Columbia and Yukon, Canada; and U-Th-Mo-REE-rich skarns and veins from the Grenville Province, Canada.
The inclusion of a broad initial chapter, incorporating both geological characteristics of skarn systems and thermodynamic aspects of ore formation into a single review-type summary, would have been good for those readers not intimately familiar with skarn systems. Therefore, this probably is not the place for new students in economic geology to begin their study of this deposit type. Nevertheless, for the more experienced economic geologist, the volume is filled with some of the most recent information on the geology and geochemistry of skarn deposits, and should be a valuable reference. The price of the soft-covered volume is quite reasonable and, therefore, I would expect it to be a welcomed and useful addition to many personal collections.