What are the divisions in the geologic time scale and how do they differ from the way we organize time using a clock?
The Earth's geologic past is divided into hierarchical time periods. This hierarchy comprises eons, eras, periods, epochs, and ages, from largest to smallest. The Cenozoic, Mesozoic, and Paleozoic Periods are the three main divisions of the Phanerozoic.
The Geologic Time Scale
Eons: Eons are large and indeterminate spans of time and are divided into four classifications: Phanerozoic (last 542 million years), Proterozoic, Archean, and Hadean. Of them, only the Hadean is not divided into ages. The ages are characterized according to the different positions of continents, oceans, and their living beings. Within the ages are divided in the periods. Epochs, in turn, are divisions within periods and are divided into ages. According to researchers, we currently live in the Quaternary period of the Cenozoic era.
To better understand the concept of geological time, we can use analogies. For instance, if the entire history of the planet were summarized in the twenty-four hours of a day, the existence of humanity would have occurred in the last three seconds of that day.
The geological time scale differs from the way we organize time using a clock because the planet's time is too long for us to use measures of hours. It is a way to categorize and study the Earth's history, providing a framework for understanding the vast spans of time involved.
Role of Man in Geological Time
Understanding the dimension of geological time and its scales of measurement becomes a fascinating mental exercise to better comprehend the role of man in relation to this temporality and his role as the heir of all the transformations that have taken place in terrestrial space throughout the geological ages.