1. Today:
We are going to talk about the ocean floor and sea floor spreading.
Then, you will have an activity to work on.
You may find this PowerPoint on my website under Chapter 3 section 3, if you do not get all of the notes down today.

2. Figure 3-11 CONTINENTAL SHELF.

3. Figure 3-12 (a) FORMATION OF CONTINENTAL SHELF.

4. Figure. 3-12 (b) FORMATION OF CONTINENTAL SHELF.

5. Figure 3-12 (c) FORMATION OF CONTINENTAL SHELF.

6. Figure 3-12 (d) FORMATION OF CONTINENTAL SHELF.

7. Coral reef, volcano, or island Water-deposited sediment
Sediment from beach erosion
Sediments
Continental rock
Continent
Wave-cut terrace
Subsurface rock
Coral reef, volcano, or island
Water-deposited sediment
River
River sediment
Continental rock
Continental rock
Stepped Art
Fig. 3-12, p. 56

8. Ocean Bottom
Ocean basin – covers slightly more of the Earth’s surface than the continents.
abyssal plains- These plains extend from the seaward side of the continental slope and are formed by sediments
Hills – rise as high as 1,000 meters, cover as much as 50% of the Atlantic Seafloor, and as much as 80% of the Pacific and Indian Oceans.
Seamounts – a steep sided formation that rises sharply form the bottom. All form from volcanoes and are most prevalent in the Pacific.

9. ridges and rises – a continuous series of large, underwater, volcanic mountains.
trenches and island arcs – very prominent in the Pacific ocean and are usually associated with volcanic islands called island arcs.
Life on the ocean floor
continental shelves are highly productive – much sunlight, shallow water – receive high levels of nutrients washed up from land.
life on the abyssal plains is not abundant, no sunlight, no photosynthesis

10. Figure 3-13 LANDSCAPE OF THE OCEAN FLOOR.

11. Figure 3-14 OCEAN TRENCHES.

12. Table 3-2 Depth of Major Ocean Trenches

13. Composition of the Seafloor
Sediment—loose particles of inorganic and organic material
Table 3-3 Composition of the Seafloor

14. Composition of the Seafloor
Hydrogenous sediments
formed from seawater through a variety of chemical processes
e.g. carbonates, phosphorites, manganese nodules
Biogenous sediments
formed from remains of living organisms
mostly particles of corals, mollusk shells, shells of calcium carbonate or silicious planktonic organisms

15. Figure 3-15 BIOGENOUS SEDIMENTS.

16. Composition of the Seafloor
Terrigenous sediments
produced from continental rocks by the actions of wind, water, freezing, thawing
e.g. mud (clay + silt)
Cosmogenous sediments
iron-rich particles from outer space, land in the ocean and sink to the bottom

17. Figure 3-B AN AMPELISCID AMPHIPOD.

18. Finding Your Way around the Sea
Maps and charts
Mercator projections – Shine light through a globe to create a map.
bathymetric charts – indicates variations in ocean depth by lines that connect areas of similar depth.
physiographic charts – shows same information, but uses coloring and shading rather than lines to show depth.

19. Figure 3-16 MAP PROJECTIONS.

20. Figure 3-17 (a) BATHYMETRIC AND PHYSIOGRAPHIC CHARTS.

21. Figure 3-17 (b) BATHYMETRIC AND PHYSIOGRAPHIC CHARTS.

22. Finding Your Way around the Sea
Reference lines
Latitude – lines running parallel to the equator.
Longitude – are at right angles to latitude lines.
divisions of latitude and longitude – using both latitude and longitude, one can pin-point exactly any place on Earth.

23. Figure 3-18 (a & b) LATITUDE AND LONGITUDE.

24. Figure 3-18 (c) LATITUDE AND LONGITUDE.

25. Finding Your Way around the Sea
Navigating the ocean
principles of navigation
a sextant was used to determine latitude based on the angle of the North Star with reference to the horizon
longitude determined using chronometer – a clock that keeps precise time.

26. Figure 3-19 A SEXTANT.

27. Finding Your Way around the Sea
Navigating the ocean
Global Positioning System (GPS)
utilizes a system of satellites to determine position
GPS measures the time needed to receive a signal from at least 3 satellites, and calculates position

28. Figure 3-20 THE EARTH’S TIME ZONES.