The Sea Floor

Man's understanding of how this planet is put together and how it evolved has radically changed during the last twenty years. This great revolution in geology now usually subsumed under the concept of Plate Tectonics and its ramifications - was an outgrowth of the study of the ocean floor. In its impact on the earth sciences, it is comparable to the revolution brought about by Charles Darwin (1809-1882) a century ago. The evolution of the biosphere was the focal point at that time. We are now discussing the evolution of the lithosphere, the uppermost 100 km of the Earth. Darwin drew his inspiration from observations made during the voyage of the Beagle, and his work gave strong impetus to the first global oceanographic expedition, the voyage of HMS Challenger (1872-1875). Ever since, oceanographic research has been intimately associated with fundamental advances in the knowledge of Earth. This should come as no surprise. After all, our planet's surface is mostly ocean. This booklet is the result of our conviction that to study introductory geology and oceanography and environment al science, one needs a summary of the tectonics and morphology of the sea floor, of the geologic processes active in the deep sea and in shelf seas, and of the climatic re cord in deep sea sedi ments. Our aim is to give abrief survey of these topics.