We will provide a list of web sites with relevant information. The geologic time scale is divided into eons, eras, periods, epochs, and ages. Our activities, and the time scale for download above, ...

It was followed by the Jurassic and Cretaceous periods – at the end of the ... As a period of geologic time, the boundaries of the Triassic are defined on the basis of rocks and the fossil ...

Earth's 4.5 billion year geological history is full of death and rebirth, mass extinctions and explosions of biodiversity, with different periods ... unit of the Geologic Time Scale.

The cold periods - or ice ages - are times when the ... ago), ice ages have occurred at widely spaced intervals of geologic time - approximately 200 million years - lasting for millions, or ...

It's thought the final stages of Precambrian time were marked by a prolonged global ice age. This may have led to widespread extinctions, mirroring the bleak endings to the geologic periods that ...

The geologic record contains physical ... an NRC study will:* Assess the present state of knowledge of earth's deep-time paleoclimate record, with particular emphasis on the transition periods of ...

A Timescale is a scale used to represent periods of time. Option ... in the rock record of the Earth that is characteristic of a particular span of geologic time or environment. We will look at a few ...