Ben Oostdam's |
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SOME GEOLOGY AROUND 1960 |
Before 1960, most geologists assumed the ocean basins were permanent and very old. Kuenen had calculated the average sediment thickness to be 3 kilometers. (left, and link below): Menard (1986) "The Ocean of Truth": quoting Hess, 1960: contrast between oceans and continents |
| from Menard's Tectonics Lecture of September 23, 1960: | |||
| LAYER: |
SOUNDVELOCITY (kilometers/second) |
AVERAGE THICKNESS (kilometers) |
COMPOSITION |
| 1 | 2.15 | 0.3 | sediments |
| 2 | 4.5 - 6.3 | 1.57 |
possibly limestone, volcanics, or consolidated sediments |
| 3 | 6.4 - 7.1 | 5 | igneous |
| MOHO | 7.8 - 8.2 | 0 | inter-face (-phase?) between crust above and mantle below |