What is the geological time scale?
Q: What is the geological time scale?
A: The geological time scale is a way of organizing and understanding the Earth's past by looking at the processes which change the surface and rocks under the surface. It uses principles and techniques of geology to work out the geological history of the Earth.
Q: How do geologists use stratigraphy and paleontology?
A: Geologists use stratigraphy and paleontology to find out the sequence of events that have happened in Earth's past, as well as what plants and animals lived during different times in history. They use this information to work out the sequence of rock layers.
Q: How old is Earth?
A: The Earth is about 4.567 billion (4,567 million) years old.
Q: What are boundaries on the time scale usually marked by?
A: Boundaries on the time scale are usually marked by major geological or palaeontological events, such as mass extinctions. For example, one boundary between two periods may be marked by an extinction event that wiped out certain species from existence.
Q: What can knowledge of geologic history help with?
A: Knowledge of geologic history can help with prospecting for energy sources and valuable minerals, as well as lessening hazards like earthquakes and volcanoes in an area.
Q: What gave scientists a way to get ages for strata layers?
A: The discovery of radioactivity and invention of radiometric dating techniques gave scientists a way to get ages for strata layers found in different areas around Earth.
