Essentials of geology / Основы геологии

Why do earthquakes, volcanoes, floods, and landslides happen? What causes mountains to rise? How do beautiful landscapes develop? Do climate and life change through time? When did the Earth form and by what process? Where do we dig to find valuable metals and where do we drill to find oil? Does sea level change? Can continents move? The study of geology addresses these important questions and many more.

But from the birth of the discipline in the late 18th century until the mid-20th century, geologists considered each question largely in isolation, without pondering its relation to the others. This approach changed, beginning in the 1960s, in response to the formulation of two “paradigm-shifting” ideas that have unified thinking about the Earth and its features. The first idea, called the theory of plate tectonics, states that the Earth’s outer shell consists of discrete plates that slowly move relative to each other so that the map of our planet continuously changes. Plate interactions cause earthquakes and volcanoes, build mountains, provide gases that make up the atmosphere, and affect the distribution of life on Earth. The second idea, called the Earth System concept, emphasizes that our planet’s water, land, atmosphere, and living inhabitants are dynamically interconnected. In the Earth System, materials constantly cycle among various living and nonliving reservoirs on, above, and within the planet. Thus, we have come to realize that the history of life is intimately linked to the history of the physical Earth.