Application of geographic information system technology to the recognition of prospecting targets in the eastern half of the Tucson Quadrangle, Arizona

Groups and individuals concerned with the search for mineral deposits use a great deal of information with high spatial content to generate prospecting targets. The information is commonly in the form of maps and may be subjected to a variety of qualitative and quantitative techniques of map analysis, the objective of which is to avoid mindless wandering in the field by reducing the exploration area while retaining a high potential for success. Geographic information systems are of great interest as a means of managing map-based information. The systems are used in government but costs and complexity are slowing their acceptance in the for-profit sector. This research demonstrates low-cost software on a widely available computer system to explore five alternative methods of applying a geographic information system to the problem of generating prospecting targets. The methodology could be applied equally well to defining targets of other kinds, from sites for toxic waste disposal to candidates for mass marketing. Success of the applications is measured by their ability to reduce the exploration area while retaining a high proportion of the known mineral deposits that provide an estimate of the undiscovered deposits. Area reductions range from zero percent, a worst case, to 98%; retentions of known deposits range from 100% to 29%. Efficiency, a ratio of the area containing known deposits within the favorable area to the entire favorable area, is introduced as a comparative measure of success. The most efficient approach is more than 40 times as efficient as the least efficient. Two of the approaches demonstrated are new, and provide a formal approach to map analysis. The research demonstrates the utility and flexibility of a low-cost, raster-format geographic information system in a pioneer application to the east half of the Tucson quadrangle, an area of over 10,000 square kilometers.