Plate tectonics concept map. Ordering instructions this book was originally published in paper form in february 1996 design and coordination by martha kiger. Tektonikos pertaining to building is a scientific theory describing the large scale motion of seven large plates and the movements of a larger number of smaller plates of the earths lithosphere since tectonic processes began on earth between 3 and 35 billion years ago. Tectonics comes from the greek word meaning builder. Image from computerized digital images and associated databases available from the national geophysical data center national oceanic.
Plate tectonics is the geologic theory that earths crust is made up of rigid plates that float on the surface of the planet. To see continental positions during a particular time click on the stop button of your browser as the red arrow reaches the era of interest. According to the theory earth has a rigid outer layer known as the lithosphere which is typically about 100 km 60 miles thick and overlies a plastic moldable partially molten layer called the asthenosphere. Illustrations and production by jane russell.
The concept of plate tectonics was formulated in the 1960s. Most movement occurs along narrow zones between plates where the results of plate tectonic forces are most evident. Surface relief of the earth 1. Plate tectonics is a widely accepted model used to explain the behavior of the earths outermost rocky layer the crust which exists as a number of puzzle piece like plates that are about 80 kilometers thick.
The layer below the crust is the mantle. The mantle has more iron and magnesium than the crust making it more dense. Plate tectonics from the late latin tectonicus from the greek.