The NSS Bulletin - ISSN 1090-6924
Volume 44 Number 4: 107-110 - October 1982
A publication of the National Speleological Society

A Statistical Comparison of Joint, Straight Cave Segment, and Photo-Lineament Orientations
Charles A. Barlow and Albert E. Ogden

Abstract

A statistical comparision was made of the orientations of joints, straight cave-passage segments, low altitude photo-lineament (1:20,000) and high altitude photo-lineaments (1:120,000 and 1:250,000) in Benton County, Arkansas. A modified version of the Kolmogorov-Smirnov (K-S) test, compensating for circular (0-360°) data, was used. The area is underlain by nearly flat-lying Mississippian carbonates (Boone and St. Joe formations) on the southwest flank of the Ozark Dome.

Eight, 2 sample K-S tests were used to compare the orientation diagrams. The null hypothesis in each case is a statement of no significant difference in orientations of the 2 distributions or populations at the chosen alpha level (0.10). The results show that for low altitude photo-lineaments and straight cave-passage segments (both 50 ft and 100 ft), the orientations are similar. This suggests that low altitude photo-lineaments may be either discrete fractures or zones of weakness that control cave passage development to a significant degree. The lack of similarity of orientation of lineaments and joints suggests that lineaments may be formed in part by larger-scale processes than those forming the regional joint patterns.

Previous testing of similar data from West Virginia showed lack of a relationship between any of the parameters (Ogden, 1974). This may be due to differences in geology and hydraulic gradient. In West Virginia, the rocks are much more deformed and the hydraulic gradient is steeper. Also, many photo-linaments in West Virginia were defined by alignments of the abundant dolines, whereas Arkansas has few dolines. The West Virgina photo-lineaments are believed less likely to depict underlying fractures. Therefore, greater care in photo-lineament mapping must be taken, because an alignment of 3 or more dolines may not represent a zone of weakness.

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