Understanding Geological Time and Radioactive Dating

These flashcards cover key vocabulary and concepts related to geological time and methods of dating rocks, specifically relative and absolute age dating.

Geologic Time

A time scale used by geologists to describe the timing and relationships of events in Earth's history.

Relative Age Dating

A method of determining the age of rocks by comparing their placement with that of other rocks.

Absolute Age Dating

A method used to determine the exact age of a rock or fossil through measurement of radioactive isotopes.

Isotope

A variation of an element that has the same number of protons but a different number of neutrons.

Atomic Number

The number of protons in an atom, which determines the chemical properties of the element.

Mass Number

The sum of the number of protons and neutrons in the nucleus of an atom.

Radiometric Dating

A technique used to date materials by comparing the abundance of a radioactive isotope with its decay products.

Radioactive Isotope

An unstable isotope that decays over time, emitting radiation.

Parent Isotope

The original radioactive isotope that decays into a stable daughter isotope.

Daughter Isotope

The stable isotope that results from the decay of a parent isotope.

Half Life

The time required for half of the quantity of a radioactive isotope to decay into its daughter isotopes.

Decay Constant

The proportion of a radioactive isotope that decays over a specific period.

Zircon Crystals

Minerals used to date ancient rocks, containing trace amounts of uranium which can be measured for radioactive dating purposes.

Carbon-14

A radioactive isotope of carbon used for dating organic materials, with a half-life of about 5,700 years.

Uranium-Lead Dating

A radiometric dating method utilized to date rocks by measuring the ratio of uranium to lead isotopes.