Class 6 Geography Chapter 5 Complete Guide Book — Major Land Features | PunjabTest.com

Mountains are high lands rising steeply, usually over 600 m above surroundings. They form by folding (Himalayas), faulting, or volcanoes. Peaks, ranges and passes (like Khyber Pass) mark them.

Mountains give water (snow melt feeds rivers), forests, minerals and tourism — but life there is hard: cold, steep and isolated.

A mountain is not just a tall hill; height alone does not make it, steepness and a sharp rise above the land around it do. Most great ranges, like the Himalayas, were folded up when two huge plates of Earth's crust pushed together, crumpling the land the way a tablecloth crumples when you push it from both sides. Other mountains are born from volcanoes or from cracks, called faults, in the crust. Mountains matter far beyond their own slopes: their snow melts into rivers that water the plains, their forests shelter wildlife, and their passes, like the Khyber Pass, have been roads for traders and travellers for centuries. Life there is hard — cold, steep and far from markets — but without mountains, the plains below would lose much of their water.

Plateaus are high flat lands, raised above surroundings with steep sides (e.g. Potwar Plateau). Plains are low, flat lands, often formed by river deposits (alluvium) — best for farming and cities.

Most of Pakistan’s people live on the Indus Plain, where rivers, flat land and fertile soil support crops and cities.

The difference between a plateau and a plain is height, not flatness, because both are flat on top. A plateau is a high, flat table of land lifted above its surroundings, with steep sides dropping away — the Potwar Plateau is the example to remember. A plain is a low, flat land, usually built by rivers dropping fine soil, called alluvium, flood after flood, until the land is level and fertile. That is why plains, not plateaus, hold most people and farms: flat land is easy to plough, to build roads and houses on, and to water from rivers. In Pakistan, the Indus Plain is the proof — most of the country's people, crops and cities sit on it, not on the high plateaus.

Valleys are low lands between mountains, often with a river (V-shaped by rivers, U-shaped by glaciers). Deserts are very dry lands (under 250 mm rain a year): hot deserts (Thar) and cold deserts (Skardu region).

Valleys shelter farms and towns; deserts challenge life, but people adapt with camels, wells and oases.

Valleys and deserts look like opposites, but both are shaped by what is missing or present: water and ice. A river cuts down through rock like a knife, leaving a narrow V-shaped valley with the river at the bottom. A glacier, a slow river of ice, bulldozes a wide, flat-bottomed U-shaped valley instead. Deserts are defined by dryness, not heat: any land getting under about 250 mm of rain a year counts, so the hot Thar and the cold desert around Skardu both qualify. People still live in deserts, and they do it cleverly — camels for transport, wells and rain ponds for water, and oases, those green spots where underground water reaches the surface and palms can grow, as resting places and farms in the middle of dryness.

Rivers shape land: eroding upstream, depositing plains and deltas downstream. The Indus delta, where the river meets the Arabian Sea, is fertile and rich in fish.

Coasts are where land meets sea: beaches (sand), cliffs (rock), and harbours (sheltered water for ships). Karachi’s port thrives on its coast.

Follow a river from mountains to sea and you watch it change jobs. Upstream, fast and steep, it erodes — it cuts V-valleys and waterfalls into rock. Mid-course, slower and wider, it carries its load and drops the finer soil on floodplains, building the flat land farmers love. At the mouth, where it meets the sea, it drops what is left and builds a delta, a fan of rich, flat land — the Indus delta is Pakistan's example, fertile and full of fish. Coasts are where this story ends: a beach is loose sand the sea has laid down, a cliff is hard rock the sea is eating away, and a harbour is sheltered water where ships can rest safely. Karachi grew where the coast gave it exactly that shelter.

Weathering breaks rocks (by water, ice, heat, plants). Erosion carries the pieces away (rivers, wind, glaciers). Deposition drops them elsewhere — building plains and deltas.

Earthquakes and volcanoes can change land suddenly; weathering and erosion change it slowly, over thousands of years.

Three words carry this whole topic, and mixing them up costs marks, so learn them as a chain. Weathering breaks rock where it stands — rain, ice freezing in cracks, heat and cold, and plant roots all split rock apart, but nothing has moved yet. Erosion is the moving: rivers, wind and glaciers pick up those broken pieces and carry them away. Deposition is the dropping: when the river slows or the wind dies, the load falls and builds something new, a plain or a delta. Weathering and erosion work slowly, over thousands of years, grain by grain. Earthquakes and volcanoes are the exception: they can raise, crack or bury land in a single day, which is why a landscape can look ancient and still change overnight.