Landforms
Geography · भू-आकृतियां
📋Quick Overview
Landforms are natural features on Earth's surface created by erosion and deposition by agents like rivers, wind, glaciers, and sea waves. Different agents create different landforms in different stages. Rivers create V-shaped valleys, waterfalls, meanders, and deltas. Wind creates sand dunes and mushroom rocks. Glaciers create U-shaped valleys and moraines. Sea waves create cliffs, stacks, and spits. Mountains are classified into 4 types based on formation.
📖Landforms by River
| Stage | Landform | Description |
|---|---|---|
| Upper (Youth) | V-shaped Valley | Deep, narrow valley cut by river in mountains |
| Upper | Waterfall | Water falls from a cliff edge where hard rock overlies soft rock. E.g., Jog Falls (Karnataka, highest in India) |
| Upper | Gorge/Canyon | Deep, narrow valley with steep walls. Grand Canyon (USA) is the largest |
| Middle (Mature) | Meander | S-shaped curve/bend of river in flat plains |
| Middle | Oxbow Lake | Crescent-shaped lake formed when a meander is cut off from the river |
| Middle | Floodplain | Flat area beside a river that floods regularly, very fertile soil |
| Lower (Old) | Delta | Fan-shaped deposit of sediment at river mouth. Sundarbans (Ganga-Brahmaputra) = world's largest delta |
| Lower | Estuary | Funnel-shaped mouth where river meets the sea (no delta). E.g., Narmada, Tapti |
📝Landforms by Wind (Aeolian)
- •Sand Dunes — mounds of sand deposited by wind in deserts. Types: Barchan (crescent-shaped), Seif/Longitudinal (parallel to wind), Star dune
- •Mushroom Rock (Pedestal Rock) — rock eroded more at base than top by wind-blown sand, looks like a mushroom. Found in deserts.
- •Loess — fine dust/silt deposited by wind far from deserts. Very fertile soil.
- •Inselberg — isolated steep-sided hill rising from a plain in a desert (erosion remnant)
📝Landforms by Glacier
- •U-shaped Valley — wide, flat-bottomed valley carved by a glacier (vs V-shaped by river)
- •Cirque (Corrie) — armchair-shaped hollow on a mountainside where glacier originates. When filled with water = Tarn lake
- •Moraine — rock debris deposited by a glacier. Types: Lateral (sides), Medial (middle), Terminal (end), Ground moraine
- •Drumlin — elongated, egg-shaped hill of glacial deposits. Smooth on one end, steep on the other.
- •Arete — sharp, knife-like ridge between two cirques
- •Horn — pyramid-shaped peak formed when 3+ cirques erode a mountain from all sides (e.g., Matterhorn)
📝Landforms by Sea Waves
- •Cliff — steep vertical rock face formed by wave erosion at the coast
- •Sea Cave — hollow carved into a cliff by wave action
- •Sea Arch — when two sea caves on opposite sides break through, forming an arch
- •Stack — isolated pillar of rock left standing after arch collapses
- •Spit — narrow ridge of sand/shingle extending from the coast into the sea, formed by longshore drift
- •Beach — deposit of sand and pebbles along the coast by wave action
📖Types of Mountains
| Type | Formation | Examples |
|---|---|---|
| Fold Mountains | Formed by folding of Earth's crust when tectonic plates collide (convergent boundary) | Himalayas, Alps, Andes, Rockies, Ural |
| Block/Fault Mountains | Formed when a block of land is uplifted between two faults. Central raised part = Horst, Lowered part = Graben/Rift Valley | Vosges (France), Black Forest (Germany), Vindhya, Satpura |
| Volcanic Mountains | Formed by accumulation of lava and volcanic material | Mt. Kilimanjaro (Africa), Mt. Fuji (Japan), Mt. Mauna Loa (Hawaii) |
| Residual/Relict Mountains | Remains of old mountains worn down by erosion over millions of years | Aravalli (India — oldest fold mountain in world), Appalachian (USA), Nilgiri, Parasnath |