Carbonate Petrography by Pattern Recognition: GEOLOGICAL NOTES

Abstract

Carbonate rocks, although relatively simple in their basic mineralogy, include a bewildering array of constituents, textures, structures, and diagenetic features, as well as complex pore geometry. Because of their complexity, detailed quantitative studies of carbonate rocks require a large investment of time by the carbonate petrologist simply for data gathering. Conversely, if large numbers of samples are to be studied or if time and cost are important factors, relatively little information is extracted from the available samples. Derivation of petrographic data from carbonate rocks may be considered a problem of image analysis. One approach to such problems is to utilize techniques and equipment developed in the field of pattern recognition. For example, it is possible to distinguish between individual grain types, such as biotic constituents, in carbonate rocks. With this procedure, in surface and crystal texture, the reaction of different minerals to staining agents, and other differences in appearance are combined to achieve unique optical characteristics for each class of constituents. Once grains have been properly identified and delineated, individual particles can be counted, their areas measured, and statistics derived from the image. The same techniques can be applied to other rock types as well as to a wide variety of geologic images. Equipment can be computer-interfaced for immediate data reduction and display.