Erosion

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2

May link an island to the main land (tombolo)

spit = curved extension

Slide 14

Tides

Daily changes in sea levels

Tides rise (FLOOD) to produce a HIGH TIDE

And fall (EBB) (LOW TIDE)

Produced by the gravitational pull that the Sun and Moon exert on the Earth’s surface (including the oceans)

Moon/

Sun

Slide 15

This side is pulled towards the Sun and/or Moon by gravitational attraction

This side bulges out because of inertia

Therefore, there are two high tides on Earth at any one time

Slide 16

Every 24 hours 50 minutes any point on the Earth rotates through two bulges

Each location experiences 2 high (FLOOD) tides and 2 low (EBB) tides

Slide 17

Types of Coastline

Submergence and emergence changes coastlines

Pocket beaches

Slide 18

Emergent coast

Uplifted land surface

Coastal landforms are found above present sea level

a wave-cut platform when elevated - uplifted marine terrace

Slide 19

Submergent coast

Rise in sea level

Submergent coast

Landforms under water

A ria coastline is an example of submergence

Slide 20

Submergence Shorlines

Ria coast - shorline valleys eroded by rivers are submerged

has many offshore islands

exposure to waves erodes islands and headlands

Fiord coast - shoreline valleys created by glaciers are submerged

valleys are deep and straight

because of the depth, there are few beaches

Slide 21

Barrier Island Coasts

Occur on low lying coasts with gentle gradients

BARRIER ISLANDS - low ridges of sand built by waves

behind the islands are lagoons

shallow water with tidal deposits

TIDAL INLETS - gaps between the islands

Slide 22

Delta and Volcano Coasts

DELTA - deposit by rivers entering the sea

Water slows down and spreads out as it enters

Channel divides and subdivides to create DISTRIBUTARIES

Volcano coasts develop in volcanic deposits

Low cliffs form in fresh lava

Slide 23

Coral reefs

Corals build up calcium deposits to produce reefs