Played times. Print Share Edit Delete. Live Game Live. Finish Editing.
History of Earth
Chapter 5: Stratigraphy – The Story of Earth
Explore This Park. The eroded cliffs reveal 1. The oldest rocks exposed in the canyon are ancient, 1, million years old. Conversely, the canyon itself is geologically young, having been carved in the last 6 million years. An appreciation of geologic time places geologic topics such as geomorphology, the origin and evolution of the Colorado River, stratigraphy, historical geology, and paleontology in context.
Ice core basics
Many fossils are found only during certain periods in the geologic record. Scientists use these fossils to determine the relative ages of rock layers. The diagram shows relative ages of four fossils.
Geologists use radiometric dating to estimate how long ago rocks formed, and to infer the ages of fossils contained within those rocks. Radioactive elements decay The universe is full of naturally occurring radioactive elements. Radioactive atoms are inherently unstable; over time, radioactive "parent atoms" decay into stable "daughter atoms.