Absolute dating

Question 1

How do we date geological materials and events?

2 ways

Answer 1

isotrope dating
carbon - 14
used for dating boned
uraniam 238 and uranium 235
analyze the radioactive elements within
Exposure dating
photons react with particles to change elements, makes isotope, happens when not covered in ice

Question 2

what is half life of uranium 238

Answer 2

4.5 billion years

Question 3

What assumptions are made in radiometric dating of rocks?

Answer 3

closed system (No parent was added, no daughter products left the area)
no daughter products present in the beginnig
enough daughter and parents to measure

Question 4

What are the best isotopes to use for dating geologic events?

Answer 4

carbon - 14
used for dating bones
uraniam 238 and uranium 235

Question 5

What is the best type of rock to date from easiest to hardest

Answer 5

igneous - all made at once
metamorphic - case specific, sometime the pressure doesn’t reset the clock
sedimentry - hard, made of a lot of other rocks.

Question 6

Why are zircons commonly used in geochronology?

Answer 6

resistant to erosion
contains uraniums and thorium
oldest material ever dated was zircon

Question 7

What is the age of earth

Answer 7

around 4.5 billion years old

Question 8

What is the age of the univers

Answer 8

13.8billion years old