Orogeny is the process in which tectonic movements of Earth’s crust or volcanic activities form mountains. Mountains, especially those with a north–south orientation, disrupt global atmospheric circulation patterns that generally move east– west because of Earth’s rotation.

Uplifting of mountains also newly exposes rock that undergoes chemical weathering and absorbs CO₂. Moreover, higher elevations accumulate ice and snow that increases Earth’s albedo. For these reasons, times of relatively rapid mountain building—say, from 40 million years ago, when the Himalayas and Sierra Nevada first arose, until today, as these ranges continue to uplift—are usually cooler periods.

Epeirogeny

Epeirogeny  is the formation of continents and ocean basins through tectonic deformations of Earth's crust., Global distribution of land masses determines the amplitude of glacial-interglacial cycles and, at the extreme, may foster a Snowball Earth. Mid-ocean ridges, where most of the new plate material is produced, release large amounts of energy and greenhouse gases. Sea levels rise and fall as new plate materials modify the shape of ocean basins.

Teaching materials on orogeny and epeirogeny

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