The Earth’s surface is continuously modified by endogenic (internal) and exogenic (external) processes.
Weathering prepares material → geomorphic agents (running water, wind, glaciers, groundwater, waves) perform erosion, transportation, deposition.
These actions create landforms, which evolve over time.
Landform:
A small to medium–sized physical feature of Earth’s surface (e.g., valley, hill, dune).
Landscape:
A collection of related landforms forming a large tract of terrain.
Landform Evolution:
The sequential transformation of landforms through stages analogous to youth → maturity → old age.
Influencing factors:
Climate change, tectonic uplift/subsidence, nature/structure of rocks, intensity of geomorphic processes.
Most dominant agent in humid regions.
Exists in two forms:
✔ Overland flow (sheet flow)
✔ Linear flow (streams & rivers)
Sheet Erosion →
Rills →
Gullies →
Valleys (V-shaped initially)
| Stage | Characteristics |
|---|---|
| Youth | Shallow V-valleys, poor drainage integration, waterfalls/rapids, broad divides, upland meanders |
| Mature | Deep V-valleys, wider floodplains, good drainage integration, divides sharp |
| Old Age | Broad floodplains, meanders, oxbow lakes, natural levees, landscape near sea level |
Almost flat low-relief surface with isolated resistant remnants (monadnocks).
V-shaped valleys, gorges, canyons (step-like walls; wider at top).
Circular depressions on river beds created by abrasion of pebbles.
Deep depressions at waterfall bases due to falling water impact.
Deep meanders cut into hard rock due to uplift/erosion.
Abandoned floodplain steps; paired terraces appear on both sides.
Cone-shaped deposits at foot of mountains.
Multiple distributaries; coarse sediments.
Deposits at river mouth; well-stratified.
Coarse → near shore; fine → offshore.
Growth via distributaries.
Active floodplain (channel deposit)
Inactive floodplain (flood deposits + cut-off channel deposits)
Linear raised banks of coarse sediment along rivers.
Depositional features on inner bends of meanders.
Sinusoidal bends from lateral erosion + deposition.
Occur in limestone/dolomite regions.
Dominant processes:
Solution (dissolution of CaCO₃) & Precipitation.
Sinkholes (Dolines)
Circular depressions; 0.5–30m deep.
Solution sinks & Collapse sinks.
Uvalas
Coalesced sinkholes.
Lapies
Grooved, pitted limestone surfaces.
Limestone Pavements
Smooth surfaces formed after extensive solution.
Caves
Form along bedding planes; horizontal tunnels possible.
Stalactites – hang from ceiling.
Stalagmites – grow upward from floor.
Pillars/Columns – fused stalactites & stalagmites.
Continental Glacier, Valley Glacier, Piedmont Glacier
Movement due to gravity and ice mass.
Bowl-shaped hollows; contain tarn lakes.
Sharp pyramidal peaks formed by headward erosion of multiple cirques (e.g., Matterhorn).
Serrated narrow ridges between cirques.
Wide, flat floors & steep sides.
Tributary glacial valleys at higher elevations.
Drowned glacial valleys filled with seawater.
Unsorted, angular glacial debris.
Meltwater-borne sorted sediments.
Terminal, Lateral, Medial, Ground moraines.
Sinuous ridges from sub-glacial stream deposition.
Extensive deposit fields of meltwater sediments.
Streamlined hills of till; blunt stoss end, tapered lee end.
Most dynamic + frequently changing landscapes.
Erosion during storms & high-energy waves.
Deposition in low-energy environments.
(Further landforms like sea cliffs, arches, spits, bars, lagoons would follow in full chapter notes.)
| River | Glacier |
|---|---|
| V-shaped | U-shaped |
| Dominant downcutting | Abrasion + plucking |
| Narrow floor | Wide floor |
| Waterfalls common | Hanging valleys common |
| Till | Alluvium |
|---|---|
| Unsorted, angular | Sorted, rounded |
| Glacial origin | River-borne |
| No stratification | Clear stratification |
| Alluvial Fan | Delta |
|---|---|
| At mountains’ foothill | At river mouth (sea) |
| Poorly sorted | Well sorted |
| Coarse sediments | Fine sediments dominate |