Chapter: Landforms and their Evolution

• Introduction

  • Definition of Landform
  • Role of Geomorphic Agents (Running water, groundwater, glaciers, waves, winds)
  • Meaning of Geomorphic Processes (Erosion, transportation, deposition)
  • Concept of Landform Evolution (Stage of development over time)

• Running Water (Fluvial Landforms)

  • Overland Flow (Sheet wash)
  • Linear Flow (Streams and rivers)
  • Stages of Youth
    • V-shaped valleys
    • Gorges and Canyons
    • Waterfalls and Rapids
  • Stages of Maturity
    • Wider valleys
    • Meanders
    • Interlocking spurs
  • Stages of Old Age
    • Floodplains
    • Oxbow lakes
    • Braided channels
    • Deltas at the mouth

• Groundwater (Karst Topography)

  • Conditions for formation (Limestone / Dolomite regions)
  • Erosional Landforms
    • Sinks and Swallow holes
    • Dolines and Collapse sinks
    • Lapies (grooves and ridges)
    • Caves and Caverns
  • Depositional Landforms
    • Stalactites (hanging from the roof)
    • Stalagmites (rising from the floor)
    • Pillar / Column (joined stalactites and stalagmites)

• Glaciers

  • Definition and Types (Continental and Mountain glaciers)
  • Erosional Landforms
    • Cirque (armchair-shaped depression)
    • Horns and Serrated ridges (Aretes)
    • Glacial Valleys / U-shaped valleys
    • Fjords (submerged glacial valleys)
    • Hanging valleys
  • Depositional Landforms
    • Moraines (Terminal, Lateral, Medial, Ground)
    • Eskers
    • Outwash plains
    • Drumlins

• Waves and Currents (Coastal Landforms)

  • High energy vs. Low energy coasts
  • Erosional Landforms
    • Cliffs and Terraces
    • Sea caves
    • Sea arches and Sea stacks
  • Depositional Landforms
    • Beaches and Dunes
    • Bars (offshore bars)
    • Barriers, Spits, and Lagoons
    • Tombolos

• Winds (Eolian Landforms)

  • Dominant in arid and semi-arid regions
  • Erosional Landforms
    • Pediplains and Inselbergs
    • Deflation hollows and Caves
    • Yardangs and Mushroom rocks
  • Depositional Landforms
    • Sand Dunes (Barchans, Transverse, Longitudinal/Seif, Star dunes)
    • Loess (fine silt deposits)

• Landscape Evolution (Cycle of Erosion)

  • Concept of Davisian Cycle
    • Youth stage
    • Maturity stage
    • Old stage
  • Influence of Structure, Process, and Time
  • Dynamic equilibrium in modern geomorphology