1. MARINE GEOLOGY

2. Geology
Study of the development and physical characteristics of our planet’s seafloor and continents and the forces that shape them
How did the oceans and continents form?

4. Big Bang 20 billion years ago
Matter (all elements in periodic table) expanded into space
Matter clumped and planets formed 5 bya
Early on our planet is a hard rock being bombarded by other planetary bodies and experiencing volcanic eruptions

5. 82 percent of meteorite falls are chondrites
82 percent of meteorite falls are chondrites

6. Formation of Earth’s Layers
Heating (leftover radioactive heating)
Denser (Fe and Ni) material sunk to the center
Lighter (Si and O) material rose to surface
Some materials vaporized to form early oceans and atmosphere
2. Layers formed
3. Planet cools

7. Our “usual” image of Earth

8. Evidence for layers from Seismic Waves

9. http://www. windows. ucar. edu/tour/link=/earth/images/earthint_image

10. Early Atmosphere
3.5 bya
Water vapor, carbon monoxide, hydrogen sulfide, nitrogen and cyanide

11. Early Oceans
amp.wpcamr.org/archives/date/2007/12
4 bya water vapor from mantle is cooled and collects on surface.
1000’s of years of thunderstorms and rain
Low lying spots fill to become our early oceans
Water also from comets, volcanoes, meteors, geysers, rocks that contain moisture

13. Origin of the Continents
Alfred Wegener suggested the continents were not always on their present positions
Continental Drift
200mya a single landmass called Pangea broke up
Evidence
Coastlines fit like a puzzle
Similar fossils and rock formations on different continents

15. Problems With CD No mechanism for how the continents “drift”
Wegener was a meteorologist…what did he know anyway!!!

16. CRUST
thin outer layer
less dense, rocks that floated to the surface when the Earth was formed
between 35km and 70km thick.
not a continuous layer of rock
Split into plates, which are free to drift slowly across the surface of the planet.

18. Moving Plates Continents move 1 cm/yr
Boundary between plates is a fault
Seismic activity occurs at faults
The lower mantle is heated by the core which creates convection currents
Rising magma may break thru the crust at ridges like the Mid-Atlantic Ridge

20. Moving Plates
Sea floor spreading- plates move apart from rising magma at a ridge
Subduction- two plates collide and the denser plate sinks into the mantle
Forms trenches (Marianas Trench)
Trenches are the deepest parts of the ocean

22. Ocean Floor Formation Sea floor spreading is source of new ocean floor
Subduction recycles ocean floor back into the mantle
Atlantic is growing
Pacific is shrinking

23. Sea Floor Spreading Evidence
Younger rocks are found closer to the ridge
Less sediment closer to the ridge
Polarity of magnetic minerals is mirror image on either side of the ridge
N and S pole flip periodically
Minerals line up as magma cools with the N pole

26. Plate Tectonics
Unifying theory that combines continental drift and sea floor spreading
Explains the origin of, connections between earthquakes, volcanoes, faults, continental drift and sea floor spreading
Explains how oceans and its features are formed

27. Why We Have Oceans & Why The Ocean Floor Is Not Flat
en.wikipedia.org

28. Ocean Floor Topography
Average ocean depth is 3636 m
Sonar is used to map features of the ocean floor
The study of elevations and depressions is topography
Ocean Floor Topography

30. Oceanic crust is denser than continental crust sinks lower into the mantle
This is why it is filled w/ water and has become an ocean basin.

31. Younger than 200 million years Sinks into mantle
Continental crust
less dense (lighter)
floats on the mantle
km thick
3500 million years old
Oceanic Crust
6 Km thick
Younger than 200 million years
Sinks into mantle
2 Types of Crust

32. Typical Features Continental Shelf-extension of the continent
Continental Slope- steep drop off from shelf and end of the continent and it’s crust
Submarine Canyons- deep valleys in the slope created by underwater landslides or old rivers
Continental Rise- a pile of sediment that has slid down the slope
Seamounts and Guyots- Islands created by underwater volcanoes

34. Plate Tectonics and Continental Coastlines
Active margins (California)
Sites of tectonic activity -earthquakes, volcanoes, mountains,
Narrow c. shelf and steep slope ending in trench
Passive
Little to no tectonic activity
Wide shelf, pile of sediment at the bottom of the slope
Plate Tectonics and Continental Coastlines

36. C & C- mountains& earthquakes
Converging plates
O & C- oceanic subducts under continental: trenches, volcanic islands & earthquakes
O & O- one plate subducts under the other: trenches, volcanic islands & earthquakes
C & C- mountains& earthquakes
Plate Margins

37. Features of Ocean Ridges
Water is superheated (371 C) by hot magma and dissolves minerals from nearby rock
As water comes out from the rock it looks like smoke
Area with these hot springs is called a hydrothermal vent
Features of Ocean Ridges

39. Animals From Hydrothermal Vents
Bacteria are the base of the food chain
Chemosynthesis- make sugars using energy from compounds like H2S
Other vent animals include giant tubeworms, crabs, octopus, shrimp and mussels
Animals From Hydrothermal Vents

41. WHY LEARN ABOUT GEOLOGY
Nature of our planet and its changes
Impact on human life
Predicting future natural disasters

42. Distribution of our Oceans
Cover ¾ of our planet
Southern hemisphere is 80% ocean while Northern hemisphere is 60% ocean
Separate but connected basins
Include features like…
Most of the ocean bottom is an abyssal plain

43. Ocean Bottom Review
Shelf
Slope
Rise
Ocean basin

44. Continental shelf
Narrow shelf
Wide shelf

45. Continental Margins ACTIVE MARGINS PASSIVE MARGINS Trench
Abyssal plain

46. PLATE TECTONICS Outer layer of our planet move and deform Boundary
Converging
Diverging
Transform

47. EVIDENCE Continental drift Sea floor spreading Subduction Diverge
Ridges
Subduction
Converge
Trenches