Coastal Processes Quiz

Coastal Processes

• Erosion: The breaking down and wearing away of rocks and materials by wind, water, or ice. This includes chemical and physical erosion.
• Transportation: The movement of eroded material from one location to another.
• Deposition: The dropping or depositing of sediment carried by wind, water, or ice when the carrying agent loses energy. This creates coastal features.
• Wave Energy: Waves derive energy from wind; stronger waves cause more erosion. Factors influencing wave size include wind speed, duration, and fetch (distance over water).
• Hydraulic Action: The forceful impact of waves against cliffs, forcing air into cracks to widen and deepen them, weakening the rock.
• Abrasion: Rocks and pebbles carried by waves colliding and wearing each other down. This makes them smaller, rounder, and smoother.
• Attrition: Rocks and pebbles transported by waves colliding with each other and breaking apart as they're thrown against cliffs.
• Corrosion (Solution): Chemicals in seawater dissolving minerals in rocks over thousands of years.

Headlands and Bays

• Headlands: Prominent, jutting portions of land protruding into the sea. Primarily composed of hard rocks (e.g., granite) that resist erosion.
• Bays: Areas of softer rock eroded by the sea, often situated between headlands. Often featuring sandy beaches due to the gentler wave action.
• Cliff Formation: Cliffs are shaped by erosion and weathering.

Wave-Cut Platforms

• Formation: Wave-cut platforms are created when the sea erodes the base of a cliff.
• Process: A wave-cut notch is formed by erosion (hydraulic action and abrasion). As the notch widens, the cliff becomes unstable and collapses under gravity. This results in the cliff retreating inland. The debris is eroded and transported, leaving a wave-cut platform.

Eroding a Headland (Caves, Arches, Stacks, Stumps)

• Sequence: Sea attacks cracks, enlarging them through hydraulic action, abrasion, and weathering. This forms caves, which become larger. Erosion continues through headlands creating arches. The arch's roof weakens and collapses, forming a stack. Continued erosion breaks down the stack into a stump.

Longshore Drift

• Process: The movement of sand and sediments along a coastline, influenced by wave strength and impact angle. The prevailing winds dictate the direction.
• Swash: Waves move up the beach, transporting sediment with them.
• **Backwash:**Water moves down the beach back into the sea due to gravity.
• Zigzag Movement: This combined action of swash and backwash creates a zig-zag pattern of sediment transport.

Spits

• Formation: Formed by longshore drift depositing material in the sea, creating an extension of the coastline.
• **Attachment:**Typically one end is connected to the mainland, with the other extending into the water. Often found next to estuaries or river mouths.
• Marshland Formation: A salt marsh can be formed behind the spit as deposited sediment builds up.
• Vegetation Growth: Vegetation may establish on the spit over time.

Hooks

• Definition: A spit whose end develops a curve (hook) due to changing wind directions.

Beaches

• Composition: Composed of eroded materials transported and deposited by the sea.
• Formation in Sheltered Areas: Often form in sheltered areas (bays) where wave energy is reduced.
• Sandy Beaches: Typically found in bays with calmer waters.
• Pebble Beaches: Commonly form where cliffs erode and high-energy waves predominate.
• Swash and Backwash: The uprush (swash) of water on the shore and its downrush (backwash) impact the beach's formation and sediment transport.

Wave Types

• Constructive Waves: characterized by a strong swash, depositing sediment and building up beaches. Low-energy waves, with a low wave height in relation to the wavelength.
• Destructive Waves: having a strong backwash, erode the shoreline. High-energy waves, with a high wave height compared to their wavelength

Tides

• Definition: The regular rise and fall of sea level.

Geology

• Sedimentary Rocks: Formed by compacted sediments (e.g., chalk, limestone).
• Metamorphic Rocks: Formed from existing rocks subjected to high heat and pressure (e.g., marble, slate).
• Igneous Rocks: Formed from cooled volcanic lava (e.g., basalt, granite).

Rock Characteristics

• Resistance: The ability of a rock to resist erosion. Hard rocks erode slowly. Softer rocks erode quickly.
• Porosity: How easily water passes through a rock.

Tombolo

• Definition: A spit connecting the mainland to an island.

Bar

• Definition: A strip of sand deposited by longshore drift that traps seawater behind it.

Salt Marsh

• Definition: A coastal wetland flooded and drained by tides.