The earth's surface is continuously reshaped by internal (endogenic) and external (exogenic) forces. This chapter covers the endogenic side: the earth's interior, continental drift, plate tectonics, folds, faults, earthquakes, volcanoes, rocks and the rock cycle.
1. Earth's Forces and the Lithosphere
- Russia drilled the Kola Super Deep Borehole between 1970 and 1994; its deepest part, SG-3 (Star Gate), extends 12.3 km into the earth.
- Diastrophism: the process by which the earth's surface is reshaped through rock movements and displacement. It includes orogenic (mountain building) and epeirogenic (continent forming) processes.
- Endogenetic movements are slow (diastrophism) or sudden (catastrophism: earthquakes, volcanoes).
The earth is composed of the lithosphere, atmosphere, hydrosphere and biosphere. The lithosphere is the outermost rigid rocky shell of the earth, comprising the crust and the upper portion of the mantle. Greek: lithos (rocky), sphaira (sphere). The term was introduced by Joseph Barrel, an American geologist.