Geological Time
Introduction to Geological Time
Geological time refers to the vast timescale over which Earth's geological and biological history has unfolded. Spanning billions of years, geological time is divided into a hierarchy of intervals, each representing significant events in Earth's history, such as the formation of continents, the rise of life, and the mass extinctions that have reshaped the planet's biodiversity.
Understanding geological time is essential for interpreting the Earth's history, as it provides context for the processes that have shaped our planet. Geologists use various methods to measure and date geological events, allowing them to piece together the complex history of Earth.
This page explores the concept of geological time, including the geologic time scale, the methods used to date rocks and fossils, and the major eons, eras, periods, and epochs that define Earth's history.
The Geologic Time Scale
The geologic time scale is a chronological framework that divides Earth's 4.5 billion-year history into several intervals based on significant geological and biological events. These intervals include eons, eras, periods, and epochs, each representing a distinct phase in Earth's history.
The geologic time scale is used by geologists and paleontologists to organize Earth's history and to correlate geological and fossil records across different regions. It provides a timeline for the evolution of life, the formation of continents, and the major climatic and tectonic changes that have shaped the planet.
Explore this section to learn about the structure of the geologic time scale, the major divisions within it, and the key events that define each interval.
Dating Methods
Dating methods are techniques used by geologists to determine the age of rocks, fossils, and geological events. These methods are essential for constructing the geologic time scale and understanding the timing of Earth's history.
There are two main types of dating methods: relative dating and absolute dating. Relative dating involves determining the sequence of events based on the positions of rock layers, while absolute dating provides a specific age for a rock or fossil, often using radiometric techniques.
In this section, delve into the different dating methods used in geology, including radiometric dating, stratigraphy, and paleontology, and learn how these methods are used to piece together Earth's history.
Eons, Eras, and Periods
Geological time is divided into several hierarchical intervals, including eons, eras, and periods. Each of these intervals represents a significant phase in Earth's history, marked by major geological and biological events.
The largest division of geological time is the eon, which is further divided into eras. Eras are subdivided into periods, and periods may be further divided into epochs. Each interval is characterized by specific events, such as mass extinctions, the formation of mountain ranges, or the appearance of new forms of life.
Explore this section to learn about the major eons, eras, and periods in Earth's history, the events that define them, and their significance in the context of geological time.