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19 Cards in this Set

  • Front
  • Back
What are the four types of radioactive dating:
Rubidium-Strontium (Rb-Sr)
Potassium-Argon (K-40 to Ar-40)
Uranium-Lead (U-238 to Pb-206)
Radiocarbon to Carbon (C-14 to C-12)
Describe carbon dating
It is radiocarbon to carbon, it's half-life is 5,700 years, it is used to date organic things, often things during the Ice Age, but you can't use it for inorganic rocks.
Describe uranium dating.
It is uranium-238 to lead-206, it's half-life is 4.6 billion years, it can date rocks with uranium, but it is only used for rocks that are very old.
Describe Rubidium dating.
It goes from Rb to Sr, it's half-life is 49 billion years, the rocks have to be extremely old.
Descride Potassium dating
It goes from K-40 to Ar-40, it's half-life is 1.3 billion years, it can can date almost any rock of almost any age, as long as the rock has potassium (almost all rocks have potassium)
If a rock is organic, which radioactive dating method should you use?
Use the carbon-14 to carbon-12 method.
What is the difference between absolute time and relative time.
Absolute time is the actual time something was formed, it uses years. Relative time is whether something is older/younger than something else, it does not use years.
What is uniformitarianism and who came up with it?
James Hutton, one of the fathers of geology came up with it. It states that "the present is the key to the past". Basically, that means that we can assume that what happens now happened before. So, if a volcano cools and turns into basalt, we can assume that if we find basalt it was probably a volcano.
How do you find the absolute time of rocks?
radioactive dating
What is radioactivity/how does it work?
Isotopes, which have an irregular number number of neutrons, change because they feel different. They change into a new atom, and while they change, they give off energy. They change at a constant rate, never changing due to heat or pressure. A parent element changes to a daughter element.
State the different principals
Superposition, Cross-cutting, embedded fragments
What principal would you use if you had pieces of a rock in another rock
You would use the principal of embedded fragments, because the rock with pieces of the other rock must be younger, because the other rock had to be there first in order for there to be pieces of it in the other rock.
What principal would you use if you had rock layers on top of each other.
You would use the principal of superposition, saying that the upper layers are younger than the lower layers.
What principal would you use if you had a fault going through layers of rock?
You would use the principal of cross-cutting relationships, which states that a cut in the earth is younger than the rocks it cuts.
What is an unconformity?
An unconformity is a "break in history", where you don't know what happened, but you know that something happened.
What are the types of unconformities?
Nonconformity, Angular unconformity, Disconformity
What is a nonconformity?
A nonconformity is when there are unstratified rock layers, some of it erodes, and then stratified rock forms above it.
What in an angular unconformity?
An angular unconformity is when there are tilted layers of rock, they get eroded, and then horizontal layers of rock get deposited.
What is a disconformity?
A disconformity is when there are stratified layers, they get eroded, and then more stratified layers get deposited.