Quiz 1 Flashcards
Why Study the Ocean?
1. What is the world ocean? Why is there only one world ocean?
The world ocean contains 5 major geographic oceans - the Atlantic, Pacific, Indian, Arctic and the Southern.
A single world ocean emphasizes the connection between theses oceans. Oceanographers recognize that the world ocean behaves as a system of interdependent parts and processes.
Why Study the Ocean?
2. What are the major ocean basins?
the Pacific Ocean, the Atlantic Ocean, The Arctic Ocean, the Indian Ocean, and the Southern Ocean.
Why Study the Ocean?
3. What are the different spheres of consideration on Earth?
Atmosphere, Biosphere, Geosphere, and hydropshere
Why Study the Ocean?
4. What is composition of Earth’s atmosphere?
The Earths Atmosphere is made up of gases (Nitrogen, Oxygen, Argon, Carbon Dioxide, other stuff), water vapor and dust/particle matter
Why Study the Ocean?
5. What types of questions do geological oceanographers ask?
Geographical oceanographers strive to understand processes that create and modify ocean basins and to identify the origins of the structures and features found within them. Most recently, they have focused their attention on the history of Earth’s climate as evidenced in sediments. Geological oceanographers also study deep-sea hydro thermal vents, regions of the seafloor.
Seek answers to the ocean’s secrets
Why Study the Ocean?
6. How much of the Earth’s surface is covered by ocean water?
70.8%
Why Study the Ocean?
7. Ocean water comprises what percentage of the hydrosphere?
97.2%
Why Study the Ocean?
8. What is physical oceanography?
The study of physical properties and processes in the world ocean (Waves, Tides, Beaches, Coasts and Coastal Zone Management)
Why Study the Ocean?
9. What is chemical oceanography?
The study of chemistry of the world ocean
Why Study the Ocean?
10. Why are oceanographic studies important?
Oceanography is an interdisciplinary science that involves the study of the entire ocean, from the shallow coastal areas to the deepest trenches. It involves geology, biology, chemistry, and physics. Students will learn about some of the important discoveries that oceanographers have made and some areas that they are still investigating.
Why Study the Ocean?
11. What are some of the impacts of humans on the ocean and atmosphere?
- Eat Fish
- Most drinking water comes from the ocean
- Ocean moderates climates and humans are contributing to greenhouse gases
- Oil spills
- Marine pollution
How Do We Study the Ocean?
12. Compare and contrast early and modern oceanographic studies.
Early -Expensive -Dangerous -Time Consuming -First Bathymetric Map since 1959 Modern -Interdisciplinary -Real time data acquisition
How Do We Study the Ocean?
13. Why are oceanographic studies so difficult?
The ocean can be extremely cold, pressure, darkness and corrsive conditions make it hard for humans to explore
How Do We Study the Ocean?
14. What are some methods of determining seafloor topography?
- Depth measurements
- Plumb lines
- Echo sounding
- Sediment dredges
- Shipboard magnetometers
- Submersibles/ROVs
- Remote Sensing Techniques
How Do We Study the Ocean?
15. How do you get subsurface information about the seafloor?
- Coring
- Gravity
- Piston
- Drilling
- Seismic reflection and refraction
How Do We Study the Ocean?
16. Understand the echosound method. Be able to do simple calculations.
Depth = .5* echo time * speed of sound in sea water (1500m s^-1)
How Do We Study the Ocean?
17. What have satellite-imaging techniques done for oceanographic research?
Have helped map the floor in ever-finer detail
How Do We Study the Ocean?
18. The deep sea is best explored via what means?
- Gravity or piston corer
- Underwater photography
-ROV (Remotely Operated Vehicle)
Megageography of the Earth
19. What are the relative proportions of land and water on the earth?
Land = 29.2% Ocean = 70.8%
Megageography of the Earth
20. What is the distribution of topography relative to sea level? What is this graph called?
- Average elevation of land is 840 meters while average elevation of oceans is 3729 meters. Ocean has a higher elevation
- Hypsographic Curve
Megageography of the Earth
21. What controls topography of the seafloor.
Isostacy: things will level themselves based on density
density =mass/unit volume
Megageography of the Earth
22. What is the average depth of the oceans?
3729 Meters
Megageography of the Earth
23. Why are the average and maximum depths of the oceans greater than the average and
maximum heights of the continents?
Ocean crust is more dense than continental crust
Megageography of the Earth
24. What are the dominant rock types of ocean basin crust and continental crust? How are
they different?
Ocean crust = Basalt (Density = 2.9 gm/cm)
Continental crust = Granite (Density = 2.7 gm/cm)
-Ocean crust is older and more dense
Megageography of the Earth
25. What is isostasy? Be able to explain its importance.
-the balance between the mass of the crust and the buoyant forces of the mantle that permit the crust to “float” on the mantle. Things will level themselves out based on density
Megageography of the Earth
26. Be able to label a cross-section of an ocean basin. What are its different parts
(physiographic or marine provinces)? What are the characteristics of each region?
Marine Provinces
- Continental Margins
- Continental Shelf
- Continental Slope
- Deep Ocean Basin
- Continental Rise
- Abyssal Plain
- Subduction Zones
- Oceanic Ridges
- Hydrothermal Vents
- Intraplate features
Megageography of the Earth
27. What processes are responsible for the formation of the continental rise?
he continental rise is an underwater feature found between the continental slope and the abyssal plain. This feature can be found all around the world, and it represents the final stage in the boundary between continents and the deepest part of the ocean. The environment in the continental rise is quite unique, and many oceanographers study it extensively in the hopes of learning more about the ocean and geologic history.
Before delving into specifics, it can help to have a quick overview of the major features of the ocean floor, starting with the continental shelf, a relatively shallow area of water which forms a transition between the elevated land of the continents and the open ocean. At a certain depth, the continental shelf begins to drop sharply, forming a feature called the continental slope. Unlike the continental shelf, the continental slope is rather steep, and geologists suspect that it may mark an earlier sea level in Earth’s history.
At the bottom of the continental slope, one will find the continental rise, an underwater hill composed of tons of accumulated sediments. Beyond this stretches the abyssal plain, an extremely flat area of the sea floor which is also incredibly deep. The abyssal plain hosts many unique life forms which are uniquely adapted to survival in its cold, high pressure, and dark conditions. The flatness of the abyssal plain is interrupted by massive underwater mountain chains near the tectonic boundaries of the Earth’s plates.
Megageography of the Earth
28. How do submarine canyons form? Where are they found? What are their characteristics?
-Triburtary current carve submarine canyons. They are found in continental slopes
- Cut across slope and onto shelf
- Sedimentary delivery system to the continental rise
Megageography of the Earth
29. Turbidity Currents. What are they? Why are they important in the ocean? What do
turbidite deposits look like? What is an example of a well-documented turbidity current?
What are the details of that event?
They deposit debris down slope. Layers of sediment lay on ocean floor because of this. They look like balls of dust. There is one located in the Monterey Canyon
Internal Structure of the Earth
1. What are three compositional layers of the Earth?
Crust, Mantle, and the Core
Internal Structure of the Earth
2. How do we know the internal structure of the Earth?
Seismology
-Study of seismic wave propagation of seismic through the Earth
Internal Structure of the Earth
3. What are P and S waves? Why are they important?
P waves (primary waves) -compressional waves particle motion parallel to propagation direction -volume of material changes S waves (secondary waves) -shear or secondary waves -particle motion perpendicular to propagation direction -material is distorted -CANT travel through liquids
-Helps predict earthquakes
Internal Structure of the Earth
4. What are the 5 rheological layers of the Earth? What are they characteristics of each of
these layers?
-Lithosphere
Crust (rigid,rocky out layer that is also brittle)
-Asthenosphere
Capable of flow; transition zone
-Mesosphere
Solid
-Outer Core
Liquid (Fe and Ni)
-Inner Core
Solid (Fe and Ni)Internal Structure of the Earth
5. What is the composition of ocean crust? Of continental crust?
Ocean crust -Rich in Fe, Mg, Ca, Mn,and Ti minerals Continental crust -Si, Al, Na, K-rich minerals 95% igneous and metamorphic rock 5% sedimentary rocks (4% shale, .75% sandstone, .25% limestone)
Internal Structure of the Earth
6. How did the Earth obtains its structure?
Homogeneous Accretion (layers formed on top of each other)
Plate Tectonics
1. How are plate margins defined?
By the lithospheric plates
Plate Tectonics
2. What is continental drift? What evidence is used to support continental drift?
-the movement of the continents over geologic time
- rock types
- Fossils
- absolute ages
- climate record
- paleomagnetism
Plate Tectonics
3. What evidence is used to support the theory of plate tectonics?
- jigsaw puzzle match
- matching fossils across fossil basins
- matching rock strata across ocean basins
- Climate records in rocks
Plate Tectonics
4. Be able to explain the evidence that supports plate tectonics.
a
Plate Tectonics
5. Where is the oldest seafloor found in a given ocean basin? The youngest?
youngest is near mid ocean ridge, while oldest is under neath or closest to continental coast
Plate Tectonics
6. Describe sediment thickness across an ocean basin.
a
Plate Tectonics
7. What are the three types of plate boundaries? Give an example of each.
Divergent along the eastern African rift system
Convergent in atlantic ocean, off himalays in india, and off coast of japan
transform san andreas fault
Plate Tectonics
8. What processes are active at each of these types of plate boundaries?
Divergent (ocean crust/basalt is created)
Convergent (crust is destroyed at subduction zones)
Transform (Lithospheric plates slide past one another, form perp to MORs)
Plate Tectonics
9. Where is ocean crust created? What type of plate boundary?
Divergent boundaries
Plate Tectonics
10. Where is crust destroyed? What type of plate boundary?
Convergent
Plate Tectonics
11. What is the main driver of plate tectonics?
Mantle convection
The Ocean Basin Cycle
12. What are the 7 stages of the ocean basin cycle?
- Conception Stage: None
- Embryonic Stage: East African rift valleys
- Juvenile Stage: Red Sea
- Mature Stage: Atlantic, Artic Ocean
- Declining Stage: Pacific Ocean
- Terminal Stage: Mediterean Sea
- Suturing Stage: India-Eurasia Collision, Himalaya mountains
The Ocean Basin Cycle
13. Be able to give examples of each step in the ocean basin cycle.
- Conception Stage: None
- Embryonic Stage: East African rift valleys
- Juvenile Stage: Red Sea
- Mature Stage: Atlantic, Artic Ocean
- Declining Stage: Pacific Ocean
- Terminal Stage: Mediterean Sea
- Suturing Stage: India-Eurasia Collision, Himalaya mountains
The Ocean Basin Cycle
14. How long do ocean basins typically persist?
a
The Ocean Basin Cycle
15. Be able to describe each stage of the ocean basin cycle.
- Conception Stage: Crustal unwarp - elevation of continental crust, beginning of rifting and volcanism
- Embryonic Stage: Uplift - complex system of rift valleys and lakes on continent
- Juvenile Stage: divergence - Narrow sea with matching coasts. Ocean ridges formed
- Mature Stage: divergence - ocean basin with continental margins. ocean continues to widen at oceanic ridge
- Declining Stage: convergence - subduction begins. Island arcs and trenches form around basin edge.
- Terminal Stage: convergence - oceanic ridge subducted, narrow, irregular seas with young mountains
- Suturing Stage: convergence and uplift - mountains forms as two continental crust masses collide, are compressed and override
The Ocean Basin Cycle
16. What is a passive continental margin? What are its characteristics? Give an example.
Atlantic-type continental margins not near a plate boundary dominated by sedimentary processes.
-changing thermal structure
-changing drainage conditions
-coral reefs and drainage
South America provides a great example. The Amazon River, whose source is in the Andes Mountains (the active margin) drains east across the interior of South America to the coast, where it enters the Atlantic Ocean and deposits the tremendous volume of sedimentary materials it eroded from the continent.
The Ocean Basin Cycle
17. What are the characteristics of an active tectonic margin? Give an example.
An active continental margin is found on the leading edge of the continent where it is crashing into an oceanic plate. An excellent example is the west coast of South America. Active margins are commonly the sites of tectonic activity: earthquakes, volcanoes, mountain building, and the formation of new igneous rock. Because of the mountainous terrain, most of the rivers are fairly short, and the continental shelf is narrow to non-existent, dropping off quickly into the depths of the subduction trench
