Geological Time Scale
The geological time scale is a system of chronological dating that relates geological strata to time. It is used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships between events that have occurred during the Earth's history.
Key Concepts
- Eons: The largest division of time on the geological time scale. The current eon is the Phanerozoic eon, which began around 541 million years ago.
- Eras: The second largest division of time, which are further divided into periods. Examples of eras include the Paleozoic, Mesozoic, and Cenozoic eras.
- Periods: Subdivisions of eras, characterized by specific geological and biological events. For example, the Jurassic period is part of the Mesozoic era.
- Epochs: The smallest units of geological time, which are further divided into ages. The Holocene epoch is the most recent epoch, which began around 11,700 years ago and continues to the present day.
Study Guide
- What is the geological time scale and why is it important in Earth science?
- Identify the major divisions of the geological time scale and provide examples of each.
- Explain the significance of the boundaries between geological time periods, such as the K-T boundary.
- Describe the events that mark the beginning and end of the Mesozoic era.
- Compare and contrast the different epochs within the Cenozoic era.
By understanding the geological time scale, scientists can interpret the Earth's history and the evolution of life on our planet. It provides a framework for studying past geological events, climate changes, and the emergence of different species over millions of years.
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EARTH AND SPACE SCIENCE
Earth’s Systems
Use evidence to explain how different geologic processes shape Earth’s history over widely varying scales of space and time (e.g., chemical and physical erosion; tectonic plate processes; volcanic eruptions; meteor impacts; regional geographical features, including Alabama fault lines, Rickwood Caverns, and Wetumpka Impact Crater).
Provide evidence from data of the distribution of fossils and rocks, continental shapes, and seafloor structures to explain past plate motions.
Use models to explain how the flow of Earth’s internal energy drives a cycling of matter between Earth’s surface and deep interior causing plate movements (e.g., mid-ocean ridges, ocean trenches, volcanoes, earthquakes, mountains, rift valleys, volcanic islands).