Question 61 / 1 ptsEarly geologists did not have radiometric dating techniques, or long layer-counted histories. Instead, they followed William Smith in putting things in order, and then used uniformitarian calculations based on modern rates of processes and observed results ofprocesses in the geologic record. These early geologists, using these techniques, foundthat the Earth:
Question 71 / 1 ptsOne practical radioactive system used to date lava flows involves:
Question 81 / 1 ptsYou start with 400 parent atoms of a particular radioactive type, which decays to give stable offspring. You wait just long enough for three half lives to pass. You should expect to have how many parent atoms remaining (on average):25.
Correct! 50. 400. 100. 200. After one half-life, you’ve gone from 400 parents to 200; after a second half-life
Question 91 / 1 ptsYou are asked to assign as accurate a numerical age as possible (how many years old) to a sedimentary deposit. You would be wise to use:
You've reached the end of your free preview.
Want to read all 28 pages?
- Summer '14
- Geology, the Canyon