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Historic Geology Study Guide
Relative Dating
1. List each type of fossil and an example of each.
Trace fossil- indirect evidence of life
Mold- hollow depression
Cast- replica of fossil created from the mold
Original remains- actual remains of the plant or animal
Replaced remains- remains replaced by rock forming minerals
2. What is the principle of superposition?
Undisturbed sequence of strata, the older rock will be on the bottom and the younger will be on top
3. What is the principle of cross-cutting relationships?
Igneous intrusion is always younger than the rock it has intruded
4. Analyze the rock layers and place them in order from oldest to youngest.
Limestone, Sandstone, Shale, Basalt
5. What is an unconformity?
Where layers of rock are missing from the rock sequence
6. When Earth deposits sediment into strata, it will always lay (horizontally or vertically).
Absolute Dating
7. What is a half-life?
The rate at which a radioactive isotope decays into the daughter isotope
8. How do scientists find the absolute age of a rock? Describe this process.
Scientists need to identify the amount of parent isotope to the daughter isotope and determine this ratio. Using
this ratio, they can determine the number of half lives that have pasted and then multiply this by the length of
the half life. This is called radiometric dating.
9. Carbon-14 can only be used for what kind of material? organic
10. Define parent isotope: original radioactive isotope
11. Define daughter isotope: the product of the radioactive decay
Geologic Time Scale
12. List the order of the units of time from largest to smallest.
Eon, Era, Period, Epoch
13. On the geologic time scale, the farthest back in time is located at the (top or bottom).
Natural Resources
14. What makes a resource renewable? The rate at which it is consumed is slower than the rate at which it is
created.
15. Fill in the chart for the sources of energy.
Energy Source
18.
19.
20.
Con
Requires $ for active system, not
useful in areas with little
sunlight, pollution from creation
of solar panels
“ugly” wind turbines, birds and
bats are killed, requires large
area
Nuclear waste, risk of meltdown
Solar
renewable
passive system requires little $
Wind
renewable
non polluting
Nuclear
efficient
Can be used anywhere
Water
renewable
nonpolluting
Only available in areas with
water, dams alter ecosystems
Geothermal
Clean, nonpolluting
Thermal pollution, expensive
Coal/petroleum/oil
Cheap, coal is available in the US
CO2 emissions, fine particulate
air pollution, oil is found
overseas, oil spills
Virginia Geology
16. Label the provinces of Virginia.
17.
Pro
Piedmont
Valley and Ridge
Appalachian Plateau
In which province is Loudoun County located?
Piedmont
Which province was created last from sediment from the mountains?
Blue Ridge
Coastal Plain
Which province is known because of its anticlines and synclines?
Valley and Ridge
Which province contains the fossil fuel coal?
Appalachian plateau
Coastal Plain