Notes

🌊 COASTAL LANDFORMS -- simplified
Erosional
Headlands and Bays
Form on coasts with alternating hard and soft rock
Soft rock erodes faster (hydraulic action + abrasion) → forms bays
Hard rock resists erosion → sticks out as headlands

Cliffs & Wave-cut Platforms
Waves erode base of cliff → wave-cut notch
Notch grows → cliff becomes unstable → collapses
Process repeats → cliff retreats
Leaves behind a flat wave-cut platform

Caves → Arches → Stacks → Stumps
Waves exploit cracks in a headland → cave
Cave deepens → breaks through → arch
Arch roof collapses → stack
Stack erodes → stump

Depositional
Beaches
Form by deposition of sand/shingle
Constructive waves (strong swash, weak backwash) build them up

Spits
Form by longshore drift
Sediment moves along coast
Coastline changes direction → sediment deposited into sea → spit
End may curve (hook) due to wind/waves

Bars & Lagoons
Spit grows across a bay → forms a bar
Water trapped behind = lagoon

Sand Dunes
Wind blows sand inland from beach
Sand trapped by obstacles → builds up
Plants stabilise dunes over time

🏞️ RIVER LANDFORMS
Upper Course
V-shaped Valleys
Vertical erosion dominates
River cuts downwards
Weathering + mass movement steepen sides → V shape

Interlocking Spurs
River flows around harder rock
Erodes vertically, not sideways
Creates winding ridges → spurs

Waterfalls & Gorges
Hard rock over soft rock
Soft rock erodes faster → step forms
Water plunges → erodes plunge pool
Undercutting → collapse → waterfall retreats
Leaves steep-sided gorge

Middle & Lower Course
Meanders
Helicoidal flow moves water side to side
Outer bend: erosion (river cliff)
Inner bend: deposition (slip-off slope)

Oxbow Lakes
Meander neck narrows due to erosion
Flood cuts through → straight channel
Old loop cut off → oxbow lake

Floodplains
Flooding deposits fine sediment (alluvium)
Builds flat valley floor over time

Levees
During floods, heavy material dropped first at river banks
Builds raised edges → levees

Estuaries
River meets sea
Tidal action deposits sediment
Forms wide, tidal mouth

🌋 TECTONIC & VOLCANIC LANDFORMS
Volcanoes
Composite Volcanoes
Form at destructive plate boundaries
Viscous lava + ash layers build steep sides

Explosive eruptions
Shield Volcanoes
Form at constructive boundaries
Runny lava spreads far → wide, gentle slopes

Plate Boundary Landforms
Fold Mountains
Plates collide (compression)
Sediments fold upwards → mountains

Ocean Trenches
Oceanic plate subducts under another
Forms deep trench

Mid-Ocean Ridges
Plates move apart
Magma rises and solidifies → ridge

Rift Valleys
Plates pull apart
Land drops between faults → valley
❄️ GLACIAL LANDFORMS
Arêtes & Pyramidal Peaks
Two corries erode back → arête (ridge)
Three+ corries → pyramidal peak

U-shaped Valleys
Glacier erodes valley sides and floor
Widens + deepens → U shape

Depositional
Moraines
Deposited rock carried by glacier
Types: lateral, medial, terminal