Structure and stratigraphy at or near the earth's surface can be identified and defined by photogeomorphic mapping methods. Processes necessary to proper photogeomorphic mapping are somewhat similar to geologic mapping processes.

Some geomorphic features that contribute information with respect to structure and stratigraphy include trellis drainage, annular drainage, radial or centrifugal drainage, centripetal or interior drainage, drainage deflection, arcuate drainage, linear stream segments, barbed tributaries, channel pattern variation, antecedent and super-imposed drainage, entrenched meanders, oblate tonal variations, tone halos, fracture traces, geomorphic lineaments, curved tonal features, drainage divides, glacial land forms and landslide debris. With proper symbolization and application of these symbols to geomorphic data, structure and stratigraphy can be mapped in a manner that produces data pertinent to oil exploration programming.

When photogeomorphic criteria are delineated in areas of good or poor outcrop expression and density, the resulting map presents both areas of anticlinal folding and (or) associated fault relationships as well as stratigraphic delineation. Use of photogeomorphic interpretation in areas where surface geologic mapping is difficult is a pertinent application of this tool for exploration.

Photogeomorphic features exist at the earth's surface due to the influence of surface rocks, climate, and vegetative growth. Tectonic adjustment so subtle as to be overlooked by normal geologic mapping techniques may be apparent through the use of definitive photogeomorphic mapping. A detailed familiarity with known structure and stratigraphy within the area of study is imperative. In the Cenozoic, emphasis should be directed toward physiographic development for proper application of geomorphic data. The photogeomorphologist must be adequately prepared to discern misleading information and to concentrate on those data that are indicative of favorable conditions for oil or gas entrapment. A method of compilation for photogeomorphic analysis is suggested as well as a tentative programmi g for analysis of the criteria.

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