The geologic time scale is an essential tool for understanding the history of Earth and the evolution of life. In this article , explore the principal eons, eras, periods, and epochs that help us track major events in geologic history. The Geologic Time Scale The geologic time scale is a c...
Time Periods in History Periodization, or grouping time periods in history, became common practice as historians began to chronicle historical events. The designations assigned to these time periods vary between cultures and even historians, and these eras are frequently subdivided into distinct periods...
Explore the earliest civilizations, from prehistory to the early modern era, and how their developments are used to differentiate each point in...
Geological history is not counted in specific years but in ranges of time divided into eras, periods, and epochs. Geologists use a variety of methods to identify the age of rocks, including measuring the decay of radioactive isotopes, to determine when certain geological even...
While there have been some important settlement site excavations from the early historic period, especially of early cities, archaeological investigation tends to focus on the study of monuments, their architecture,art historyand inscriptions. It is notable that South Indian early cities are substantially...
In the 19th century, geologists divided Earth history into three major eras, based largely on fossil types preserved in the various strata. Each era was divided into periods, and each period was further divided into epochs. Many of these were marked by mass extinction events. Recently, global ...
Evolution has taken life on earth through different types of species. The evolution of life on Earth is classified into different eras and periods. These periods are identified by popular species of the time or notable events in history.
Notable Uses of Sculpture in the Classical & Hellenistic Eras Attic Grave Monuments Grave monument for a young athlete, circa 550 BCE, Kerameikos cemetery in Athens. Source: the Archaeological Museum of Athens Attica, the region surrounding Athens, was known for its distinctive burial rites and int...
The period is the basic unit of geological time in which a single type of rock system is formed. Two or more periods comprise a geological Era. Two or more Eras form an Eon, the largest division of geologic time. Some periods are divided into epochs. ...
Of course, these geologic units are not equal in length. Eons, eras, and periods are usually separated by a significant geologic event and are unique in their climate, landscape, and biodiversity. The Cenozoic era, for example, is known as the "Age of Mammals." The Carboniferous period, on...