Geologic Time Crossword

This printable crossword puzzle on the topic of Rocks & Minerals has 12 clues. Answers range from 3 to 17 letters long. This crossword is also available to download as a Microsoft Word document or a PDF.

A unit of time equal to a billion year.
A division of time that is a subdivision of a period and is itself subdivided into ages.
A major division of time that is a subdivision of an eon and it itself subdivided into periods.
The remains or traces of an organism preserved from the geologic past.
The division of earth's history into blocks of time eons, eras, periods.
The time required for one-half of the atoms of a radioactive substance to decay.
A fossil that is associated with a particular span of geologic time.
Basic unit of the geologic time scale that is a subdivision of time.
The spontaneous decay of a certain unstable atom nuclei.
Method of determining the age or date of organic matter from the relative proportions of the carbon isotopes carbon-12 and carbon-14.
A method of dating geological or archaeological specimens by determining the relative proportions of particular radioactive isotopes present in a sample.
The science of determining the relative order of past events without determining exact age.