History Unwritten

Informashort #2: what’s with all the timelines.

In many articles you'll read terms like Neolithic, holocene, glacial and bronze age but what does it mean exactly?

Basically there are four major timelines where these exotic keywords come from.  

Timeline of “human prehistory, human history, natural history, ice ages”. The first two obviously handle the natural stages as to the last two handle the human history in its different stages. I deliberately excluded the timeline of the universe since it has little relation to the article’s we write about. The goal of this article is to give a broad overview of all the timelines.

Timeline of natural history:

The timeline of natural history talks comprises dates in millions of years can be divided into four major era’s:

- The hadean era

The period between 4.6 - 4.0 billion years ago which handles the formation and the early stages of earth when the rocks where molten.

- The archean era

Between 4.0 - 2.5 billion years ago which handles the early formation of life and continents.

- The proterozoic eon

Between 2.5 - 0.541 billion years ago which start with the appearance of oxygen to just before the formation of complex life.

- The phanerozoic era

Between 0.541 - present which handles the different stages of the formation of life and the drifting of the continents.

Because of the enormous extent of the study material the above is a short representation.

Timeline of ice ages:

There have been at least five major ice ages in the Earth's history the Huronian, Cryogenian, Andean-Saharan, Karoo Ice Age, and the current Quaternary Ice Age.

Every ice age can be divided into a cooler and warmer period called glacial and interglacial.

  • Huronian,  2.4 - 2.1 billion years
  • Cryogenian, 720 - 635 million years ago
  • Andean Saharan, 450 - 420 million years ago
  • Karoo, 360–260 million years ago
  • Quaternary, 2.58 - present

Timeline of human prehistory:

This timeline of human prehistory comprises the time from the first appearance of Homo sapiens in Africa 300,000 years ago to the invention of writing and the beginning of historiography, after 5,000 years ago. Divided into three major different ages.

  • Middle paleolithic
  • Upper paleolithic
  • Holocene

Timeline of human history:

Period from the beginning of written history until present day

  • Stone age
  • Bronze age         (prehistory)
  • Iron age

  • Middle age
  • Renaissance (history)
  • Modern age


The primary defined divisions of time are eons, in sequence the Hadean, the Archean, the Proterozoic and the Phanerozoic. The first three of these can be referred to collectively as the Precambrian supereon. Eons are divided into eras, which are in turn divided into periods, epochs and ages.

The following four timelines show the geologic time scale. The first shows the entire time from the formation of the Earth to the present, but this gives little space for the most recent eon. Therefore, the second timeline shows an expanded view of the most recent eon. In a similar way, the most recent era is expanded in the third timeline, and the most recent period is expanded in the fourth timeline.



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