Nature · Earth Science
Earth’s crust folded, faulted and forged skyward
A mountain is a landform that rises prominently above its surroundings, usually with steep slopes and a defined summit. Born from the slow collision of tectonic plates or the fire of volcanism, mountains shape climate, guide rivers and host unique ecosystems layered by altitude.
Most mountains are built by tectonic forces acting over millions of years. Where plates collide, rock buckles into folds or snaps along faults; where magma rises, volcanoes stack lava into peaks. Weathering and glaciers then sculpt the raw uplift into ridges, horns and valleys.
Compressed rock strata arch into anticlines and dip into synclines, with a deep “root” of crust below and altitude zones above.
Crust crumpled by colliding plates
When two plates converge, thick layers of sediment are squeezed and buckled upward into folds. The Himalayas are still rising today as India ploughs into Asia — the classic young fold range.
Great blocks lifted along fractures
Tension in the crust breaks it into blocks along faults; some rise as “horsts” while others drop as “grabens”. The result is a dramatic steep scarp on one side and a gentle slope on the other.
Land pushed up into a broad blister
When a large body of magma pushes the overlying rock upward without breaking through, it creates a broad dome. As the softer top erodes, concentric ridges of harder rock are revealed around an ancient core.
Built grain by grain from erupted rock
Volcanic mountains grow as successive eruptions pile lava and ash around a vent. Many of the world’s most iconic solitary peaks — perfectly conical and snow-crowned — are volcanoes.
Highlands carved by water and time
Rather than being pushed up as peaks, these highlands are what remains after rivers dissect a raised plateau. Resistant flat-topped remnants stand as mesas and buttes above eroded valleys.