Geologic time scale
Escala de tiempo geológico
- Date
- 1822-1841 · confidence medium
- Place
- London, United Kingdom (Geological Society)
- Credited to
- Adam Sedgwick, Roderick Murchison, Charles Lyell, John Phillips (Palaeozoic/Mesozoic/Cenozoic, 1841)
- People
- 👤 Adam Sedgwick1785–1873👤 Charles Lyell1797–1875👤 John Phillips1770–1823👤 Roderick Murchison1792–1871
- Field
- Cosmos & Earth
What was discovered
British and European geologists defined the Cambrian, Silurian, Devonian, Carboniferous and Permian systems and the Mesozoic periods, and Phillips grouped them into eras according to changes in fossil fauna. This created the calendar of Earth's history.
Coordinates of the Geological Society of London, the forum for the Sedgwick-Murchison controversies. Absolute dates arrived with radiometry in the 20th century.
What it led to
- Chronological framework for evolution and palaeontology
- International Commission on Stratigraphy
- Recognition of mass extinctions at era boundaries
Built on
- Steno's principles of stratigraphy1669
- Primary, secondary and tertiary mountains (Arduino)1759-1760
- Uniformitarianism and deep time1788 / 1830
- Paris Basin: succession of strata by their fossils (Cuvier and Brongniart)1808-1811
- Silurian and Cambrian systems (Murchison and Sedgwick)1835
- Smith's stratigraphy
Made possible
- Radiometric age of the Earth: 4.55 billion years1956
- Iridium layer and impact hypothesis for the K-Pg extinction1980
- The 'Big Five' mass extinctions1982
- Global geological mapping
- Geochronology