This document summarizes different landforming processes and the landforms they create. It discusses the erosional and depositional work of rivers, which creates features like V-shaped valleys, waterfalls, meanders, ox-bow lakes, flood plains, and deltas. It also describes how sea waves can form sea caves, sea arches, and stacks. Moving ice is discussed as well, noting how it forms cirques, tarns, and glacial moraines. Finally, the document covers wind processes in deserts and the landforms they shape, such as mushroom rocks, loess deposits, and sand dunes.

1. MAJOR LANDFORMS
Class 7
NCERT
Chapter- 4

2. • Weathering – disintegration and decomposition
of rocks by agents like heat, cold, frost action and
chemical reactions
• Erosion- process by which broken rock materials
are removed from place of origin and deposited
elsewhere
• Landforms are created by various agents of
erosion and deposition

3. WORK OF RIVER
• Area drained by river- river basin
• River originates at source; river joins another
water body is mouth
• Running water carries out work in 3 ways-
Erosion
Transportation
Deposition

4. EROSIONAL WORK OF RIVERS
V-shaped valley(due to widening and deepening of
river valley)
Waterfall(river flows vertically down a steep
valley)
Highest waterfall in India(Jog falls on Sharavati
river, Karnataka; 260m)
Highest waterfall in the
World (Salto Angel Falls,
Venezuela; S.America; 975m)

5. DEPOSITIONAL WORK OF RIVERS
• Meanders- large bents or loops formed when the
rivers twists and turns
• Ox-bow lake- loop left behind i.e. completely cut-
off from the main channel
• Flood plain- the fertile part of the fine alluvial soil
brought by the rivers during floods
• Natural levees- long ridges of low height coarse
materials formed along the banks
• Sand bars-deposition of excess alluvium at the
mouth of the river
• Delta- triangle shaped land formed between
distributaries due to deposition of sediments

6. WORK OF SEA WAVES
• Aided by currents, tides and storms
• Sea caves- splashing waves create cavities on the rocks; on
widening these cavities form caves
• Sea arch- passage created on the headland projecting into the
sea due to wave action
• Stacks- pillars of rock on standing water
• Sea cliff- steep vertical
wall facing the sea
• Beaches- deposition of
sand, gravel & pebbles on shore
• Lagoon- partially enclosed
lake

7. WORK OF MOVING ICE
• Snowfields- accumulation of snow which falls in high
altitudes and latitudes
• Glacier- moving river of snow and ice
• Cirque- deep armchair like depressions along the slope
of mountains
• Tarn- depression filled up with water and forms a lake
• Glacial moraines- rock
materials deposited on sides
and floor of the valley when
carrying capacity of glacier
reduces

8. WORK OF WIND
• Most effective agent of erosion in deserts
• Ideal height of wind deposition- 25 to 75cm
• Mushroom rocks- narrow base and broad top
rocks
• Loess- fine dust particles deposited
extensively
• Sand dunes- coarse particles
deposited in the form of hillocks