Compilers: Walter C. Pitman III, Roger L. Larson, and Ellen M. Herron
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These charts show the patterns of magnetic lineations and interpreted basement ages that have been mapped over most of the deep-sea floor in the past decade. The basic data for these studies are magnetic anomaly profiles that are made by towing total-field magnetometers across the ocean basins behind ships or airplanes. After the regional field is removed from the magnetic measurements, the characteristic anomalies that remain can be correlated from track to track. The magnetic anomaly maps are superposed on maps of fracture zones, many of which offset the magnetic lineations at right angles. The resulting lineation chart (shown in black and white) is a map of the world's ocean basins that is similar to a geologic section, except that the time planes are vertical instead of horizontal. In a sense, the interpretation is more straightforward than in classic stratigraphic, because the features correlated (the magnetic anomalies) are considered to be exactly time synchronous, whereas correlated fossils or physical characteristics of a geologic stratigraphic section often are not. Also shown as dots on one chart arc earthquake epicenters.
Published: 10/30/1974
Pages: 2, plus 2 sheets
Product Category: Maps and Charts