Geology Test: 18 - Geologic Time

What scientific development made accurate numerical dating possible?

• development of radar

• discovery of radioactive dating

• discovery of x-rays

• correlation of rock layers

Atoms of the same element with different number of neutrons are called _______________.

• ions

• isotopes

• molecules

• polarized

What is radiometric dating?

• a technique where the decay of radioactive isotopes is measured and used to determine the age of a geologic material.

• a process where the nucleus of an atom is split apart to release energy

• a logical approach to putting events into their correct order

• all of these

What is a half-life?

• half the time it takes for the parent isotope to decay to the daugher isotope

• the parent isotope half, of a radiometric dating pair

• half of the alpha particles necessary to decay at a steady rate

• the amount of time it takes for half of the unstable parent isotope to decay into the stable daughter product

A isotope with a half-life of 1.5 million years is used to measure the age of a rock. How old is the sample if the parent/daughter ratio is 12.5% to 87.5%?

• 4.5 billion years

• 1.5 million years

• 4.5 million years

• 375,000 years

What kinds of materials are best dated using carbon-14?

• sandstones

• volcanic rocks

• igneous rocks

• organic matter

What term is used for the radioactive, unstable isotope?

• parent

• daughter

What term is used for the stable isotope formed through radioactive decay?

• parent

• daughter

A paleontologist researching dinosaurs would use carbon-14 to date the ages of the dinosaur fossils.

• true

• false

What is a fossil?

• the remains or traces of once living things

• only the skeletal structures that have been preserved

• a really old teacher

• mudcracks preserved in rock