ABSTRACT: Photointerpretation of Side-Looking Airborne Radar Imagery of the Paducah Quadrangle for Lineaments

STOHR, CHRISTOPHER, Illinois State Geological Survey, Champaign, IL

Linear drainage patterns are often formed in response to geologic structures, such as faults and prominent fractures. In unglaciated, southern Illinois, southeastern Missouri, and northern Kentucky 27% of all lineaments identified on side-looking airborne radar (SLAR) imagery were coincident with known structures. Imagery showing known structures was used to interpret lineaments in areas where detailed mapping is incomplete. Seven criteria used to identify lineaments include: (1) linear and curvilinear drainage, (2) drainage pattern, (3) wide valleys with linear segments and escarpments, (4) wide mouth at confluence of streams, (5) orientation of drainage, (6) topographic expression of structure, and (7) prominent changes in imagery texture or tone not attributable to shadowing or mos icking.

Lineaments were identified by both single and multiple criteria. Natural features can exhibit distinguishing criteria either distinctively or ambiguously.

A total of 266 lineaments were identified on the U.S. Geological Survey 1:250,000 SLAR mosaic of the Paducah Quadrangle. Of the total, 33 (12%) were coincident with known structures, 39 (15%) were coincident with known structures extended by interpretation of the SLAR imagery, 175 (66%) were probable traces not coincident with known structures, and 19 (7%) were weakly manifested lineaments not coincident with known structures. One syncline could be matched with drainage indications on the SLAR imagery, but two other known synclines could not be identified.

AAPG Search and Discovery Article #91013©1992 AAPG Eastern Section Meeting, Champaign, Illinois, September 20-22, 1992 (2009)