F O R E W O R D

This is the third in a series of special "Conceptual Models" volumes on exploration geochemistry; the first describing the Canadian Cordillera and the Canadian Shield; the second, Norden. A fourth volume on Australia is in preparation. It is hoped that further volumes will follow and also that the original volumes will be updated from time to time as important new advances are made in the understanding of exploration geochemistry in any region.

There are two important differences between these "Conceptual Model" volumes and normal issues of the Journal of Geochemical Exploration which provide case history and research papers or " theme volumes". First, an a t tempt is made to give a complete review of all aspects of exploration geochemistry for a given area or region and to describe the uses of geochem- istry in a series of simplified models. It is an important factor that details of all these models are substantiated by case histories. Second, conclusions are given as to where exploration geochemistry will not work using available technology, as well as where it will. It is customary practise to publish only successful case histories and it is generally only in a volume such as this that negative examples, which are quite as important to the exploration geologist as positive examples, are readily published.

The editors and compilers of this volume have addressed themselves particularly to the problem of geochemical exploration for buried and blind deposits. This is a critical aspect of any exploration method in any relatively well explored area, such as the Basin and Range Province. As such, this volume is very timely. However, the experience gained in this area, which is so aptly summarized in this volume, has application in many areas of the world.

October 1977 P.M.D. BRADSHAW Chairman, Case History Committee Association of Exploration Geochemists