Radioactive dating of rock samples multiple choice question?

Question

Radioactive dating of rock samples

a. is a method of absolute dating

b. is a method of relative dating

c. forms a geologic column

d. forms a geologic time scale

which one is it and please explain!

thank you

Answer 1

Many minerals forming the rocks have radioactive elements which decay through a fixed rate and form daughter isotopes.

with rate of decay  known, the proportion of parent to daughter elements give the time of formation of the mineral/rock through the half life concept.

Thus this estimate is absolute radiometric dating.

The other methods of dating is always relative to the age of underlying or overlying formation (rocks) or mutual inclusion concepts (cross-cutting relation of rocks -intrusion or extrusion etc.)

thnks

Answer 2

a

Radioactive dating uses radioactive decay to find the exact age of something like a rock.

Lets say you have a rock with a radioactive mineral X which decays into mineral Y. Every month, half of X turns into Y (half life = 1 month). You can use the percentage of X and Y to figure out how old the rock is.

If you have 25% X and 75% Y, Your rock is 2 months old.

Answer 3

a

Many radioactive elements can be used as geologic clocks. Each radioactive element decays at its own nearly constant rate. Once this rate is known, geologists can estimate the length of time over which decay has been occurring by measuring the amount of radioactive parent element and the amount of stable daughter elements.

The proportion of parent to daughter tells us the number of half-lives, which we can use to find the age in years.