The Classifications of Metamorphic Rocks and Their Applications to Air Photo Interpretation Procedures,
ARMY ENGINEER TOPOGRAPHIC LABS FORT BELVOIR VA
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Although there are stated Army needs for rock-type information, there are as yet few reliable procedures for obtaining much of this information, particularly for metamorphic rocks, via remote sensing. The three common classifications of metamorphic rocks, i.e. textural, facies, and formational, were evaluated in terms of their usefulness in predicting metamorphic rock types using air photo interpretation procedures. Areas in the northeastern United States containing a wide range of metamorphic rocks were selected as test areas. Predictions of rock type were verified by field reconnaissance and comparison to geologic maps. Although none of the three classifications were found adequate for use on air photos, the results of this study indicate that the potential for successfully predicting metamorphic rock types by air photo interpretation procedures exists. The textural classification was found most useful, primarily because criteria for identifying metamorphic rocks on air photos using this classification were developed previously. Although using the facies classification has potential, it is unlikely that it can be used routinely in conjunction with air photo interpretation procedures because of the high degree of skill required to identify metamorphic facies. The formational classification was found to be useful because it identifies metamorphic rocks by mapping unit, but it does not provide a mechanism for naming the rock units.
- Cartography and Aerial Photography
- Geology, Geochemistry and Mineralogy