Geomorphological features

Updated 10 Oct 2026

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Sample Note : Geomorphological Features

#GS-I #PhysicalGeo #Prelims Source: NCERT XI Fundamentals of Physical Geography (Landforms & their Evolution) + PYQs

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“Landscape is a function of structure, process and stage.” — W. M. Davis

Geomorphology = study of landforms & the processes that shape them. Two sets of forces → endogenic (from inside: diastrophism, volcanism → build relief) vs exogenic (on the surface: weathering, mass wasting, erosion → wear relief down). Exogenic landforms = agent-wise questions, imp. for Prelims.

1. Big picture — agents of gradation

flowchart LR
  EX([Exogenic forces]) --> WE[Weathering]
  EX --> MW[Mass wasting]
  EX --> ED[Erosion and deposition]
  ED --> RW[Running water]
  ED --> GL[Glacier]
  ED --> WI[Wind]
  ED --> WA[Waves]
  ED --> GW[Groundwater]
  RW --> RW1["Gorge, waterfall / meander, delta"]
  GL --> GL1["Cirque, horn / moraine, esker"]
  WI --> WI1["Mushroom rock / barchan, loess"]
  WA --> WA1["Cliff, stack / beach, spit, lagoon"]
  GW --> GW1["Sinkhole / stalactite, stalagmite"]

Every agent does 3 jobs: erode → transport → deposit. Erosional forms where energy is high, depositional where it drops (gentle slope, less velocity, more load).

2. Running water (fluvial) — most imp.

Erosional landforms

V-shaped valley → gorge / canyon — vertical erosion in the upper course.

Gorge: deep, steep, almost as wide at top as at bottom; forms in hard rocks. e.g. Indus, Sutlej & Brahmaputra gorges in the Himalaya.

Canyon: steep step-like sides, wider at top; forms in horizontally bedded sedimentary rocks. e.g. Grand Canyon; in India, Gandikota on the Penna (AP) is called the “Grand Canyon of India”.

Waterfall — hard rock over soft rock → differential erosion; plunge pool at the base.

Jog Falls — Sharavathi, Karnataka (~253 m); Kunchikal Falls — Varahi, Karnataka (~455 m, tiered; often cited as India's highest).

Dhuandhar Falls — Narmada at Bhedaghat (Jabalpur); the river then cuts the Marble Rocks gorge.

Potholes — pebbles swirled by eddies drill round holes into the bed; big ones at a fall's foot = plunge pools.

Depositional landforms

How an oxbow lake forms (draw this once, it sticks):

Outer (concave) bank → fast water → erosion → river cliff; inner (convex) bank → slow water → deposition → point bar.

The loop keeps growing, so the neck of the meander keeps narrowing.

In a flood the river cuts straight across the neck → shorter path.

Silt seals off the old loop → oxbow lake. e.g. Kanwar Lake (Kabartal), Begusarai — oxbow of the Burhi Gandak; Bihar's first Ramsar site (2020).

Mains tip: a 4-step labelled sketch (meander → narrow neck → cut-off → oxbow) earns more than a paragraph. Practise it in 60 seconds.

Meanders, point bars and cut-off oxbow lakes of the Red River, Arkansas (USA). Photo: USDA/FSA, public domain, via Wikimedia Commons

Alluvial fan — where a hill stream enters a plain; e.g. Kosi megafan, the bhabar belt.

Floodplain & natural levees — Ganga plains; levees are highest right next to the channel.

Braided channels & river islands — Brahmaputra; Majuli (Assam), India's first island district.

Delta — Ganga–Brahmaputra (Sundarbans) = world's largest delta; all big east-flowing rivers: Mahanadi, Godavari, Krishna, Kaveri.

Delta vs estuary. Narmada & Tapi (west-flowing) make estuaries, not deltas — they flow through rift valleys over hard rock, carry less silt, and the strong tides of the Gulf of Khambhat scour the mouth. East-flowing rivers → deltas.

Diagram: Long profile of a river · source · mouth → sea · Upper course · V-valley, gorge, waterfall, pothole · Middle course · meanders, oxbow lakes · Lower course · floodplain, levee, delta / estuary · erosion dominates ←—— gradient falls, load rises ——→ deposition dominates

3. Glaciers

Erosional: cirque (armchair hollow → tarn lake), arête (knife-edge ridge between two cirques), horn (pyramidal peak, e.g. Matterhorn), U-shaped valley, hanging valley (→ waterfall).

Depositional: moraines (unsorted till), drumlins (“basket of eggs” topography), eskers (winding ridges of meltwater gravel), outwash plains.

India: Gangotri glacier → Bhagirathi rises at Gaumukh; Siachen (Karakoram) — among the longest non-polar glaciers; U-shaped valleys in Zanskar & Lahaul; Roopkund — high glacial lake (Uttarakhand).

CHAT-U erodes, MODE deposits. Cirque, Horn, Arête, Tarn, U-valley | Moraine, Outwash plain, Drumlin, Esker.

4. Wind (aeolian) — arid lands

Erosional: deflation hollows, yardangs, mushroom / pedestal rocks (sand-blasting is strongest near the ground → narrow stem).

Barchan — crescent dune, horns point downwind; forms where wind is constant & moderate over a flat surface. Common in the Thar (Jaisalmer, Barmer).

Seif = barchan with one wing (wind shifts); longitudinal dunes ∥ wind (poor sand supply); transverse dunes ⊥ wind.

Loess — wind-blown silt (Loess Plateau, China). Salt flats & playas: Rann of Kutch (seasonal salt marsh), Sambhar (inland salt lake).

5. Waves (coastal)

Erosional: sea cliff, wave-cut platform, sea cave → arch → stack → stump. e.g. Varkala cliffs (Kerala) — a GSI National Geological Monument.

Depositional: beaches, spits, bars, lagoons. e.g. Chilika (Odisha) — India's largest coastal lagoon; Pulicat (AP–TN); Vembanad backwaters (Kerala) — India's longest lake.

East coast = emergent (broad plains, deltas, lagoons). West coast = submergent (narrow; old Dwaraka is believed to lie submerged). Frequently asked as a statement question.

6. Groundwater (karst)

Limestone dissolves by carbonation: CaCO₃ + H₂O + CO₂ → Ca(HCO₃)₂. Erosional: sinkholes, uvalas, poljes, lapies, caves. Depositional: stalactites, stalagmites, pillars.

India: Borra Caves (Araku Valley, AP), Belum Caves (AP), Mawsmai & Krem Liat Prah (Meghalaya) — Liat Prah is India's longest known cave.

Stalactite vs stalagmite. stalaCtite hangs from the Ceiling; stalaGmite grows from the Ground. When they meet → pillar / column.

Agent-wise summary

Agent	Erosional	Depositional	Indian e.g.
Running water	Gorge, canyon, waterfall	Meander, oxbow lake, delta	Jog Falls, Kanwar Lake, Sundarbans
Glacier	Cirque, arête, horn, U-valley	Moraine, drumlin, esker	Gangotri, Siachen
Wind	Mushroom rock, yardang	Barchan, seif, loess	Thar dunes
Waves	Cliff, arch, stack	Beach, spit, lagoon	Varkala, Chilika
Groundwater	Sinkhole, uvala, polje	Stalactite, stalagmite	Borra, Belum

Odd one out: Lonar crater (Buldhana, Maharashtra) — made by none of these agents. A meteorite impact crater in Deccan basalt; its lake is saline & alkaline; Ramsar site (2020).

Mind map

# Landforms by agent
## Running water
- Erosional: gorge, canyon, waterfall, pothole
- Depositional: alluvial fan, levee, oxbow lake, delta
## Glacier
- Erosional: cirque, arête, horn, U-valley
- Depositional: moraine, drumlin, esker, outwash plain
## Wind
- Erosional: mushroom rock, yardang, deflation hollow
- Depositional: barchan, seif, loess
## Waves
- Erosional: cliff, sea cave → arch → stack
- Depositional: beach, spit, bar, lagoon
## Groundwater (karst)
- Erosional: sinkhole, uvala, polje, lapies
- Depositional: stalactite, stalagmite, pillar

Quick revision checklist

Fluvial landforms + one Indian e.g. each

Delta vs estuary — why Narmada & Tapi differ

Sketch cirque → arête → horn from memory

Locate Borra & Belum caves on the map

Solve the practice questions below without peeking

PYQ-style practice — click ▸ to reveal

Which of these rivers forms an estuary rather than a delta? (a) Mahanadi (b) Godavari (c) Narmada (d) Krishna

Ans: (c) Narmada. It flows west through a rift valley into the Gulf of Khambhat; the Tapi does the same. Frequently asked concept.

Consider: 1. Barchans form where the wind blows from a constant direction. 2. The horns of a barchan point towards the wind. Which is/are correct?

Ans: 1 only. The horns point downwind; the gentle windward slope faces the wind and the steep slip face is on the lee side.

Kanwar Lake (Kabartal) in Bihar is an example of which landform?

Ans: an oxbow lake — a cut-off meander in the Burhi Gandak floodplain; Ramsar site since 2020.

Image credits: Jog Falls, Red River meanders, Barchan dunes — Wikimedia Commons.

Erosion vs deposition at a glance

Erosional

V-shaped valley, gorge

Cirque, arête, horn

Depositional

Delta, levee, floodplain

Moraine, esker, drumlin