🌊 How the Sea Shapes the Land
The ocean is always working on shaping the land through erosion (wearing away of rocks) and deposition (dropping off materials). This happens due to waves, tides, currents, and storms. The stronger the waves and the softer the rock, the faster the erosion.
How Does the Sea Erode the Land?
- Wave Force – When powerful waves crash against rocks, the air inside cracks gets compressed. This weakens the rock, causing it to break.
- Rock Fragments as Tools – Waves carry broken pieces of rock. These fragments hit the coast, breaking down even more rock.
- Dissolving Rocks – If the rock is made of materials like limestone or chalk, seawater can dissolve it over time.
🌍 Erosional Landforms (Landforms Made by Sea Erosion)
1️⃣ Chasms (Deep Cuts in the Rock)
- Imagine a sharp knife cutting deep into a soft cake.
- Waves hit weak spots in coastal rocks, cutting deep, narrow gaps.
- Over time, these gaps grow bigger and may turn into bays (large water bodies along the coast).
2️⃣ Wave-Cut Platform (Flat Area Along the Coast)
- Waves keep hitting a cliff, breaking it down slowly.
- The land retreats, leaving behind a flat, horizontal area at the bottom.
- Think of it like scraping a block of ice—after multiple scrapes, a smooth surface remains.
3️⃣ Sea Cliffs (Steep Rock Faces at the Coast)
- When a high rock wall faces strong waves, the bottom part gets eroded first.
- Eventually, the top part collapses, forming a steep cliff.
- Example: Cliffs of Dover in England.
4️⃣ Sea Caves (Caves Along the Shore)
- Some rocks have hard and soft parts.
- Waves erode the soft parts first, forming arched caves.
- Example: The famous Blue Caves of Zakynthos (Greece).
5️⃣ Sea Arches (Rock Bridges Over Water)
- If a cave gets eroded from both sides, it turns into a natural bridge.
- Example: The Durdle Door in England.
6️⃣ Stacks (Lonely Rock Pillars in the Sea)
- When a sea arch collapses, a tall column of rock remains standing alone.
- Think of a bridge breaking in the middle and leaving its pillars standing.
- Example: The Twelve Apostles in Australia.
7️⃣ Hanging Valleys (Small Rivers Over the Sea)
- If a river reaches the sea too high up, it looks like it’s hanging before dropping down.
- Example: Waterfalls that fall directly into the ocean.
8️⃣ Blowholes (Water Fountain from Rocks)
- When waves push water into a sea cave, it finds a way out through a small hole on top, creating a spout of water.
- It looks like a whale spouting water from its blowhole.
- Example: Kiama Blowhole in Australia.
🌊 What Happens After Erosion?
9️⃣ Plains of Marine Erosion (Flat Coastal Areas)
- Once erosion slows down, the land near the sea becomes flat.
- If this plain is at the same height as the sea, it is called a peneplain (almost a plain).
Summary (In Simple Terms)
- The sea is like a sculptor, carving out caves, cliffs, and arches.
- Stronger waves + softer rocks = faster erosion.
- Over time, some features (arches) break down into new ones (stacks).
- After a long period, the land becomes a flat plain due to continuous erosion.
