Geologic Time and Radioactive Dating

What does radiometric dating use to estimate the age of geologic samples?

naturally occurring radioactive decay

When an organism dies, what happens to the amount of radiocarbon in its tissue?

It decreases consistently according to the half-life clock.

Principle of superposition

A relative age dating principle stating the oldest rocks are located the farthest down.

Choose the type of decay described here: The nucleus of an atom emits a single particle consisting of 2 protons and 2 neutrons.

alpha decay

which best describes Beta decay

the nucleus emitting a negative particle converting a neutron into a proton.

After one half-life, a sample will contain twice the number of atoms that were originally present.

false

Which of the following constitutes the largest segment of geologic time?

eon

The process in which an element spontaneously transforms itself into another isotope is called?

radioactivity

The geologic time scale is based on blank

fossil correlation

The time needed for half of the parent atoms of a radioactive substance to decay into daughter atoms is termed?

half life

Our best estimate for the age of the Earth is

4.5 billion

Which rule of relative dating would a geologist apply to determine the relative age of a fault?

cross cutting relationships

A geologist observes uplifted metamorphic rocks that are overlain by a bed of horizontal sedimentary rock layers. This is an

nonconformity

Unconformities in sedimentary rock strata indicate that:

there was a time period during which no record of deposition was preserved.

The process of correlation relies on which principle?

Successive layers of sedimentary strata contain similar sets of fossils.

What happens to all radioactive isotopes that undergo radioactive decay?

They transform into a new isotope.

Which rule of relative dating would a geologist apply to determine the relative age of an igneous intrusion?

Cross-cutting relationships

How does an angular unconformity form?

Older rocks are tilted, eroded, and overlain by younger rocks.

Time unrepresented in a rock sequence as a result of erosion is called a(an)

unconformity

Which of the following is the oldest chapter of geologic time?

Precambrian