oilfield, an additional strong east-trending regional alignment not 
previously recognized on aerial photographs or in field study, is 
expressed by elongation of some lakes, alignment of others, and by 
linear interlake areas. Andre F. Maurin (1976) has refined the ° 
empirical observations by automatic pattern analysis techniques. The 
trend of this lineament is parallel to the trend of deflections in 
contours of the magnetic and gravity fields in the area and parallel 
to westerly deflections in the northwest ends of northwest-trending 
folds mapped to the south. In addition, the alignment of many small 
lakes forms a large ellipse superimposed on the regional lineament. 
Sparse seismic profiles show periodic reversals in dip and regional 
arching in shallow strata beneath the delineated area. Collectively, 
these data suggest that heretofore unsuspected deep structures may be 
concealed beneath the younger Quaternary Gubik Formation that covers 
the area of the image. In addition, strata in shallow folds are 
younger than those tapped by the oil wells of the Umiat field to the 
south, and may contain favorable reservoir beds. 
Schmidt (1976) used enhanced Landsat imagery and computer 
classifications to examine the characteristics of known copper de- 
Posits in Pakistan. He found 19 ares that he considered to be 
potential sites for the presence of mineralized rock. Of.these, he 
was able to confirm mineralized material on the surface by field 
inspection at five of the locations. 
Rowan and others (1974) provide a detailed description of the 
development and application of a new remote-sensing technique for geo- 
logic exploration. A combination of digital computer processing and 
color compositing of Landsat Multispectral Scanner (MSS) images was 
used to detect and map hydrothermally altered areas associated with 
ore deposits and to discriminate major rock types in south-central 
Nevada. MSS spectral bands were combined by ratioing techniques, pic- 
ture element by picture element, and were subsequently enhanced by 
contrast stretching to magnify subtle spectral differences. The tech- 
nique used in the study appears to have important applications in 
mineral-resources exploration and regional geologic mapping by rapidly 
extending geologic information from well-known regions to lesser known 
areas on the basis of spectral reflectance characteristics. There is 
a probability, therefore, of shortening the time between exploration 
for and discovery of economic mineral deposits and their ultimate 
development and industrial use. 
In an investigation that was recently completed in the Nabesna 
quadrangle in east-central Alaska, large linear features that are too 
long to be recognized on conventional aerial photographs have been 
correlated with known mineral deposits (Albert, 1975; Richter and others, 
1975). The computer interpretations that used enhanced images led to 
Lentative conclusions that 56 percent of all known metallic mineral 
occurrences in this quadrangle lie within approximately 1 mile of 
  
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