The last 15 years have been of vital importance in the history of the use of planktic microfossils for the dating of Cretaceous and Cenozoic deep sea sediments. During this time, the Glomar Chall eng er of the Deep Sea Drilling Project (DSDP) has drilled at a total of 624 sites in almost every ocean basin in the world and brought up Cenozoic and Mesozoic sediment cores from the great majority of them. As the oceans occupy 72% of the surface of the Globe, the results were bound to have a profound effect on geologic thinking. A review of some of the important findings of the first ten years of the project is given in Warme et a!. (1981).

This book has grown and evolved from a course I teach at New Mexico Tech, which is taken chiefly by seniors and graduate students in the Earth Sciences. The rapid accumulation of data on plate tectonics, mantle evolution, and the origin of continents in the last decade has necessitated continued updating of the course. The book is written for an advanced undergraduate or graduate student, and it assumes a basic knowledge of geology, biology, chemistry, and physics that most students in the Earth Sciences acquire during their undergraduate education. It also may serve as a reference book for various specialists in the geological sciences who want to keep abreast of scientific advances in this field. I have attempted to synthesize and digest data from the fields of oceanography, geophysics, geology, planetology, and geochemistry, and to present this information in a systematic manner, addressing problems related to the evolution of the Earth's crust and mantle over the last 4 Gy. The role of plate tectonics in the geological past is examined in the light of geologic evidence, and examples of plate reconstructions are discussed. <...>

Plate tectonics is a major new paradigm, or scientific worldview, that profoundly changes our ideas about how the earth works. It has been compared to the Bohr theory of the atom in its simplicity, its elegance, and its ability to explain a wide range of experiments and observations.

Humans live on unsteady ground. This fact was made abruptly apparent on January 12, 2010, when a magnitude 7.0 earthquake devastated the Caribbean island nation of Haiti. Because many buildings in thisimpoverished country were poorly constructed, they could not withstand the shaking and collapsed en masse, particularly in the capital city of Portau-Prince, 15 miles from the quake’s epicenter. Rescue workers desperately combed through rubble, hunting for survivors. By early February, Haiti’s prime minister estimated that more than 200,000 people had been killed by the earthquake’s effects. This type of earthquake, caused by two separate sections, or plates, of the Earth’s crust sliding against each other is known as a strike-slip earthquake. It is just one example of the restlessness of Earth’s surface. <...>