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Definition. An epoch is a significant division of geological time that is shorter than a period and longer than an age, representing a specific interval in Earth’s history. It is used in the geologic time scale to identify and categorize major changes in the Earth's climate, life forms, and geology during that timeframe.
Concept Check. What evidence was used to build the geologic time scale? What is the difference between relative time and absolute time? How is the geologic time scale divided? Page 1 of 1. This study guide summarizes the key points of Geologic Time Scale.
From longest to shortest in relative length, those units are eons, eras, periods, and epochs. The units form a hierarchy in which each type of unit encompasses one or more smaller units—an eon contains two or more eras; an era encompasses several periods; and a period includes epochs.
The Geologic Time Scale is divided into four eons, ten eras, 22 periods, and several epochs and ages. Each eon, era, period, and epoch is defined by major geological or paleontological events. The eons are the Hadean, Archean, Proterozoic, and Phanerozoic.
For visually engaging presentations, these science slide templates allow students to exercise their creativity and make scientific posters that communicate complex concepts with illustrations, images, and scientific figures.
epoch, unit of geological time during which a rock series is deposited. It is a subdivision of a geological period, and the word is capitalized when employed in a formal sense (e.g., Pleistocene Epoch).
1. Explain the relationships among eons, eras, epochs, and periods of the geologic time scale. 2. How did scientists account for fossils and other geological evidence as they developed the geologic time scale? 3. Match the description with the appropriate subdivision of the geologic time scale. Use each term once. Description Term
