EAR 105 Lecture Notes - Lecture 4: Marie Tharp, Seafloor Spreading, Continental Drift
16 Sep 2016
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Document Summary
Sea floor spreading - new study of the sea floor provided a mechanism for continental drift. Innovator in the study of the sea floor and plate tectonics. Used depth data from scientific cruises to map the seafloor. Because she was a woman, she was not allowed on the ships. The tharp map documented the longest continuous feature on earth (mid- Ocean ridge) and formed the basis for initial theories on plate tectonics. Idea gained traction when earthquakes would occur along ridge. Mapping of the sea floor was done in concert with a wide array of sensors, one of which was a magnetometer. Magnetic anomalies were seen on the seafloor. The anomalies were relatively continuous and were mirror images on either side of the ridge. Earth"s magnetic field is preserved in magnetic minerals as lava rocks cool. Whole surface of the seafloor (not covered by sediment) is covered by basalt. Magnetic minerals align with the magnetic field.
