Abstract

For many years some geologists have been much impressed by real or imagined linear arrangements of various geologic features: drainage lines, faults, joints, volcanoes, ore deposits, and even anticlines. Such real or fancied lineaments have commonly been attributed to deep-seated wrench (strike-slip) faults. Some seem to regard the San Andreas fault as typical; others refer to zones as much as 100 miles wide as lineaments, but surely no one would suggest that a zone that wide would be a guide to ore. In this paper no zones wider than ten miles are considered lineaments.Some geologists consider lineaments to be the record of worldwide stress fields embracing the entire crust. This paper reviews some of the literature in an attempt to evaluate the significance of lineaments. I conclude that, although sea-floor lineaments--marked as they are by both magnetic and sounding evidence--are indeed important structures, the significance of lineaments in the far more heterogenous continental crust has been greatly exaggerated; the value of lineaments as guides to ore is virtually negligible. Most orebodies, even the greatest such as Butte or Bingham, are so small compared to, say, a ten-mile-wide zone, that their discovery would not be significantly facilitated even though exploration is restricted to the zone. Most postulated ore zones are more than ten miles wide, and many that have been postulated can be shown to be nonexistent.

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