Identifying Igneous Rocks in an Arid Environment on Aerial Photography by Photo Tone and Photo Texture

摘要

Work concerning identifying igneous rock types on aerial photography began in the late 1940's and early 1950's (Belcher, and others, 1951; Frost, and others, 1953). Even now, the only igneous rocks thought by many to be identifiable on aerial photography are granite, basalt, and some pyroclastic rocks (Military Geology, 1956; von Bandat, 1962; Way, 1973; and Lillesand and Kiefer, 1979). Recent work has shown, however, that other specific igneous lithologies, such as andesite and monzonite, can be identified successfully by air photo analysis (Ehlen, 1981). The purpose of this study was to determine how, and to what level of classification, igneous rocks can be identified by air photo interpretation procedures. Thus, the specific objectives were: (1) to further evaluate established igneous rock identification criteria for arid an semiarid environments, (2) to discover new photo pattern indicators for igneous rocks in these climates, and (3) to develop a classification for igneous rocks based on their photo patterns, similar to a petrologic classification.