Geoenvironmental Models

Mineral deposits have been classified by their geologic and mineralogic characteristics for decades, but the recognition that mineral deposits could be classified by their environmental characteristics is relatively new. In the past 5 years, advancements have been made by building on the earlier work of economic geologists who classified geologic characteristics. Several approaches have been taken that range from wholesale assessments of large areas (millions of square kilometres) to detailed assessments of individual watersheds or individual mines. Current efforts in the development of geoenvironmental models include the assemblage of diverse database and encompassing geologic, geochemical, geophysical, hydrologic, and other data. Although the geologic information layers are most important in classifying the environmental signatures of mineral deposits, other data, which include the delineation of ecological regions, or ecoregions, provide a framework within which geoenvironmental models can best be developed. For instance, although the economic classification of ore deposits is best accomplished by grouping geologic, mineralogic, and depositional characteristics, the environmental classification of ore deposits may be best accomplished by grouping according to geochemistry, mineralogy and hydrology within the ecoregion framework. Thus, economically different deposits in one ecoregion might have greater environmental similarities than similar deposits in different ecoregions. This is because the weathering behaviour of mineral deposits is controlled by climatic, as well as geologic, properties. This presentation provides an overview of the development of mineral deposit environmental models and discussions of the most important data types to be included in the models. This paper presents the current state of the art of geoenvironmental models, suggests a new framework for the models, and sets the stage for the topical presentations that follow in this volume.