Coastal Landforms: Cliffs, Caves, Sea Stacks, Coastal Plains

Introduction

Coasts are ever-changing places where waves shape the land quickly. Understanding coastal processes is vital because erosion and deposition can happen rapidly. Waves crashing onto the shore churn up sediment, causing significant changes. From storm waves to tsunami waves, these forces can transform coastal landscapes in no time.

Coastal Landforms: Processes, Features, and Classification

• Shaping Factors: Coastal landforms are shaped by coastal erosion and deposition and are driven by factors such as wave action, tides, currents, and sediment availability.
• Hydraulic Action: Coastal rocks disintegrate from the impact of moving water.
• Abrasion (Corrasion): Marine waves carrying sands, pebbles, and boulders erode bedrock.
• Attrition: Mechanical wear causes the breakdown of rock fragments.
• Corrosion (Solution): Chemical alteration of coastal rocks, particularly carbonate rocks.
• There are two types of coasts: 
  • High Rocky Coasts (West coast of India): Highly irregular coastline, coastline appears highly indented with extension of water into the land where glacial valleys (fjords) are present in many places. 
    • Erosion features dominate; barrier bars and spits can block bays, forming lagoons that may fill over time, creating coastal plains.
  • Low Sedimentary Coasts (East Coast of India): Mainly deposition occurs. Depositional features dominate like coastal plains, bars, spits, lagoons, and deltas. 
    • These coasts have a smooth appearance with lagoons and tidal creeks. The land gently slopes into the water, and marshes and swamps may be present.

Enroll now for UPSC Online Course

Coastal Erosional Landforms

• Capes and Bays:  On exposed coasts, the continual action of waves on rocks of varying resistance causes the coastline to be eroded irregularly. 
  • Capes and Bays are particularly pronounced where hard rocks, like granites and limestones, occur in alternate bands with softer rocks.
• Softer Rocks: These are worn back into inlets, coves or bays and the harder ones persist as headlands or capes.
• Wave Cut Cliffs: Waves break forcefully against rocky coasts, forming cliffs; 
  • Constant wave impact causes cliffs to recede, creating wave-cut platforms where eroded material is deposited. 
• Wave Cut Terraces: Flat platforms made of rock debris at the base of cliffs, elevated above the average wave height. 
  • Wave-cut cliffs and terraces are major landforms where erosion is the dominant process.
• Caves: Hollows formed by the impact of waves and rock debris against cliffs. \
  • roofs of these caves collapse, giving way for stacks.
• Sea Stacks: resilient rock masses, originally part of cliffs or hills, standing alone just off the shore.
• Stumps: In the course of time, these ‘stubborn’ stacks will gradually be removed. 
  • The vertical rock pillars are eroded, leaving behind only the stumps which are just visible above sea level.
• Wave-Cut Platforms: flat surfaces created by waves pounding in front of cliffs. 
  • These flat, slightly concave surfaces are formed in front of cliffs due to the relentless pounding of waves. 
• Arches: Natural arches are formed when caves on opposite sides of a headland merge over time.

Conclusion

Coastal processes shape our shorelines with constant change. From the erosion of cliffs to the formation of caves and arches, nature’s forces sculpt diverse landforms. Whether it’s the rugged beauty of sea stacks or the gentle slopes of coastal plains, each feature tells a story of waves at work. Understanding these processes is key to appreciating the dynamic and ever-evolving nature of our coasts.

DOWNLOAD PDF