1. QUICK QUIZ 1.Give an example of an Continental Island 2.Name one of the three parts of a Ridge. 3.An area of Subduction will form what type of structure in the ocean? 4.What is a flat topped Seamount called? 5.Long Island and England are what type of Islands?

3. Island Formation How do Islands form? Island Arcs- Philippines Hot spots---The Hawaiian Islands What does Darwin have to do with this? Atolls and Coral reefs

4. 1. Continental Islands = UK, New Zealand. 2. Island arcs – Philippine & Aleutian Islands 3. Volcanic Islands- a. volcanic = Iceland, Hawaii, Azores, etc. (1) along mid-ocean ridges, or (2) mid-basin “hot spots”. b. coral - atolls (1) formed in warm, clear, tropical oceanic waters. (2) have volcanic bases.

5. Continental Islands Large chuck of land breaks off of a continental land mass. Ireland, England were originally part of the European continent (fig 2.14 p 31) New Zealand was part of Australia

6. Which Island can the Mid Atlantic Ridge be seen on land. 1.Ireland 2.Iceland 3.Finland 4.Greenland 5.It cannot be seen on land

7. The three part of a ridge are the 1.Flank, Ridge and slope 2.Flank, Ridge Valley and Base 3.Flank, Rift Valley and Crest 4.Slope, Break and Shelf

8. An example of Island Arcs created through subduction are 1.Iceland 2.Hawaiian Islands 3.Manhattan Island 4.The Islands of Japan

9. The most common geological structure in the ocean is 1.Abyssal Plains 2.Seamounts 3.Guyots 4.Abyssal Hills

10. Oceanic Crust – Continental Crust

11. B. Island Arcs 1. arc-shaped chains of islands (Marianas, Aleutians) 2. usually on continent side of trenches. 3. made by active volcanoes - explosive type. 4. marginal basins a. between arcs and continents b. serve to trap sediment and block it from the deep sea. Aleutian Islands

12. Island Arc Formation

13. Hot Spots-Volcanic Islands A volcanic “plume” at a fixed spot in the mantle pushes through the crust creating a volcano. The volcano builds becoming a seamount which crests the ocean surface. The crust moves over the spot and the process is repeated. This is why you will get Island Chains such as the Hawaiian Islands

14. Hot Spot Formation

20. Volcanic Features The Island Of Hawaii

29. Coral Reefs Tropical waters only (temperature matters) 20 – 30 degrees C Form in shallow water next to island As island erodes, reef remains Can only live in Photic zone- If the Island (Atoll) sinks below the photic zone the coral will die. Photic Zone is the upper layer of water where light can penetrate.

30. Largest reef –Great Barrier Reef covers 80,000 square miles

31. Charles Darwin

32. Darwin In his voyage around the world in the 1830’s Darwin formulated his theory on reef and atoll formation This theory is still considered valid and is used to this day

33. Life of a coral reef (as per Darwin) Fringing reef Barrier reef Atoll