Geosphere Final Exam Study Guide · 2017-11-30 · 1. Name and describe Earth’s 4 major spheres...

Geosphere Final ExamStudy Guide

1. Name and describe Earth’s 4 major spheres

Geosphere-- nonliving, mostly solid rock divided into crust, mantle, and core

Chapter 1Intro to Earth Systems

Atmosphere– a life-sustaining, thin, gaseous envelope surrounding earth

Biosphere– includes all life on earth

Hydrosphere-- all of the water on earth

2. What are fossil fuels? How are they formed?

Chapter 4Interactions with the Geosphere

• A carbon-containing fuel that formed over millions of years from the remains of living things.

• Ex: Coal (plant material), petroleum (plants and animals buried in ancient seas), and natural gas (plants and animals buried in ancient seas)

3. What is the rock cycle? Describe how a rock can be transformed from an igneous rock, to a sedimentary rock, and then to a metamorphic rock.

• The rock cycle describes how each type of rock can be transformed from one type to another

Chapters 3, 5, and 6Earth’s Changing Surface

• Igneous rock would need to be weathered, eroded away, and deposited in layers. The layers would need to be compacted and cemented together into a sedimentary rock.

• Sedimentary Rocks pushed deep into the earth that are under intense heat and pressure are transformed into metamorphic rocks

4. What is the difference between weathering, erosion, and deposition?

• Weathering– the breakdown of rock into sediments• Erosion– the picking up and carrying away of sediments• Deposition– the dropping of sediments


5. Describe the 2 categories of weathering. Explain the difference and provide and example.

• Mechanical Weathering— physical forces break rock into smaller pieces without changing the rock’s composition• Ex: Frost wedging, roots growing between rocks

• Chemical Weathering– transformation of rock into 1 or more new compounds• Ex: Water creating acid rain that eats away at

limestone, or causes rust on metal structures

6. How does running water affect sediments?• Running water erodes soil and can cause sediments to

be moved far from their origin.• Humans have drastically increased the amount of

sediments carried by rivers


7. What is a mass movement? What causes them?

• The transfer of rock and soil downslope due to gravity• 4 Triggers:

• Saturation of surface materials with water• Over-steepening of slopes• Removal of vegetation• Earthquakes

8. List the layers of the Earth in order, starting from the surface:

Chapters 8, 9, and 10Earth’s Structure and Plate Tectonics

• Crust• Mantle• Core

• Using seismic waves• P & S waves travel at different speeds through

different materials

9. How do we study the interior of the earth?

10. What is the continental drift hypothesis? What were Wegener’s 5 pieces of evidence to support it?


• The continents had once been joined to form a single supercontinent

1. Continental jigsaw puzzle2. Evidence of glacial scarring in areas too warm today

for glaciers3. Evidence of tropical plants (coal deposits) in areas too

cold today for tropical plants4. Fossils of same organism across oceans that couldn’t

have swum5. Matching rock types across continents

11. What is the theory of plate tectonics?


• Earth’s surface is broken into plates that move slowly relative to one another

• The process of new ocean floor forming along Earth’s mid-ocean ridges and slowly moves outward across ocean basins

12. What is sea-floor spreading and where does it occur?


• Magnetic strips in ocean floor rock• Earthquake patterns• Measurements of the ages of ocean floor rocks

• More dense oceanic lithosphere sinks beneath less dense lithosphere– recycles back into the mantle

• Deep ocean trenches and earthquakes occur with volcanic mountains or islands

13. What evidence do scientists have that sea-floor spreading actually occurs?

14. What is subduction? What occurs at subduction zones?


• Convergent: mountains, deep ocean trenches, volcanoes, earthquakes

• Divergent: rift valley at mid ocean ridges, earthquakes• Transform: earthquakes

• C-C: mountains & earthquakes (Himalayas)• C-O: Deep ocean trenches, volcanic mountains,

earthquakes (Andes Mountains in S. America)• O-O: Deep ocean trenches, volcanic islands, earthquakes

(Japan)

15. What occurs at a convergent boundary, divergent boundary, and transform?

16. What is formed at continental-continental collisions, continental-oceanic collisions, and oceanic-oceanic collisions?


• Due to differences in temperature and therefore density of magma in the mantle• Hot, Less dense magma rises• Cool, more dense magma sinks

17. Why do convection currents occur?

18. Define relative dating.

Chapter 12Earth’s History

19. What is the law of superposition?

20. What is an index fossil?

• Fossils of organisms that lived during a relatively short, well-defined geologic time span (trilobites)

• Determining whether an object or event is older or younger than other objects or events

• The principle that states that younger rocks lie above older rocks in undisturbed sequences

21. Define absolute dating.


22. What do scientists use Carbon-14 to date? Uranium-238? Why can’t they use the same isotope for both?

23. How old is the earth (so far)?

• 4.6 Billion-ish years old

• Any method of measuring the age of an event or object in years

• Carbon-14 is used to date once living things• Uranium 238 is used to date rocks• Carbon-14 has such a short half life, the amount of

radioactive isotope remaining would be too small to measure

24. List the 3 Geologic Eras from Youngest to oldest. What life dominated each era?

Cenozoic Era


Mesozoic Era

Paleozoic Era -- dominated by fish, Amphibians, Early Reptiles, Land plants emerge

-- Early birds appear, first flowing plants, dinosaurs dominant

-- Mammals, primates, and humans

Geosphere Final Exam Study Guide · 2017-11-30 · 1. Name and describe Earth’s 4 major spheres...

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