Across
- 1. a scientific method that can accurately determine the age of organic materials as old as approximately 60,000 years
- 5. one of the principles of geology scientists use to determine the relative ages of rock strata, or layers
- 6. the emission of energy in the form of ionizing radiation
- 8. divides up the history of the earth based on life-forms that have existed during specific times since the creation of the planet
- 9. method of age determination that makes use of the radioactive decay of uranium-238 to uranium-234
Down
- 2. a measure of how old it actually is in years
- 3. The amount of time that it takes one half of the atoms present to decay
- 4. the process of determining if one rock or geologic event is older or younger than another, without knowing their specific ages
- 7. the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes and rivers