The Geological History of South Gloucestershire

This section gives an introduction to the geological periods represented in South Gloucestershire and the rocks that can be seen associated with the different periods of time. The largest divisions of geological time shown on geological maps known as the periods. Beginning with the youngest at the top the following list is represented in South Gloucestershire.

These larger blocks of time are sub-divided into series, or groups on newer maps. The names of the series, where given, and represented in South Gloucestershire, are presented in each separate section. Both of these types of sub-division relate to time and are termed chronostratigraphical units. In addition to age rocks are given names according to their type. These are lithostratigraphical units and they will be introduced in each section.

Click on a period to learn more about it.

Era Period / Epoch Age At Base (millions of years)
Cenozoic Holocene .01 (=10,000 yrs)
Pleistocene 2
Pliocene 5
Miocene 24
Oligocene 42
Eocene 58
Paleocene 64
Mesozoic Cretaceous 135
Jurassic 204
Triassic 250
Palaeozoic Permian 295
Carboniferous 360
Devonion 408
Silurian 435
Ordovician 510
Cambrian 545
Ediacaran ?
Pre-Cambrian 4600