- Quaternary (Wikipedia)
The Quaternary (/kwəˈtɜːrnəri, ˈkwɒtərnɛri/ kwə-TUR-nə-ree, KWOT-ər-nerr-ee) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. As of 2023, the Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today); a third epoch, the Anthropocene, has recently been proposed, but it is not officially recognised by the ICS.
- Chalcolithic (Wikipedia)
The Chalcolithic (also called the Copper Age and Eneolithic) is an archaeological period characterized by the increasing use of smelted copper. It follows the Neolithic and precedes the Bronze Age. It occurs at different periods in different areas, and is absent in some parts of the world, such as Russia. Stone tools were still predominantly used during this period.