Volcanic Activity & the Atmosphere
Specification Point 8.18:
Recall that the gases produced by volcanic activity formed the Earth’s early atmosphere
- The surface of the early Earth was molten for millions of years during which time there was no atmosphere surrounding the planet.
- Eventually cooling began to take effect and allow for molten materials to slow and solidify forming land masses.
- Volcanoes formed on the land masses and released gases from the Earth’s interior through violent eruptions.
- Earth’s gravity prevented the gases from escaping into outer space and they formed the atmosphere.
Composition of Earth’s Early Atmosphere
Specification Point 8.19:
Describe that the Earth’s early atmosphere was thought to contain:
a) little or no oxygen
b) a large amount of carbon dioxide
c) water vapour
d) small amounts of other gases and interpret evidence relating to this
- Analysis of the gases conserved in the fossil record has allowed scientists to perform studies of the composition of Earth’s early atmosphere.
- It is thought that the atmosphere at that moment in Earth’s history was similar to that of Venus or Mars today, which consist mainly of CO2.
- During a period of intense volcanic activity, large amounts of carbon dioxide and water vapour were released, as well as nitrogen, hydrogen, ammonia, methane and other gases.
- The early atmosphere therefore contained mainly CO2 and water vapour.
- There was little or no oxygen present.
Volcanoes spewed out water, carbon dioxide and other gases from the Earth’s interior
Edexcel GCSE Chemistry Notes
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