8.1.2

Carbon Stores 2

Test yourself

Geological Processes that Release Carbon

Carbon can be released into the atmosphere via the rock cycle.

Illustrative background for Chemical weathering of rocksIllustrative background for Chemical weathering of rocks ?? "content

Chemical weathering of rocks

  • Chemical weathering is the wearing away of rock by chemical reactions, causing material to dissolve through solution, hydrolysis and oxidation.
  • Slightly acidic rain (a carbonic acid) forms from carbon dioxide in the atmosphere being dissolved into rainwater.
  • When acidic rain hits carbon-rich rocks (e.g. limestone) it can dissolve material and form calcium carbonate.
  • These dissolved materials are then transported down rivers and deposited into the sea, forming into sedimentary rock.
Illustrative background for Volcanic out-gassing Illustrative background for Volcanic out-gassing  ?? "content

Volcanic out-gassing

  • Extreme heat from tectonic processes leads to sedimentary rock undergoing chemical changes, causing CO2 to be released into the atmosphere.
  • Volcanic activity happens at two types of plate boundaries:
    • Constructive plate boundaries, where two plates move apart.
    • Destructive subduction zones, when an oceanic plate subducts under a continental plate.
  • Volcanic activity at these plate boundaries causes CO2 to be released in out-gassing.
    • Out-gassing is common in geothermal locations like New Zealand.

Jump to other topics

1Tectonic Processes & Hazards

2Option 2A: Glaciated Landscapes & Change

3Option 2B: Coastal Landscapes & Change

4Globalisation

5Option 4A: Regenerating Places

6Option 4B: Diverse Places

7The Water Cycle & Water Insecurity (A2 only)

8The Carbon Cycle & Energy Security (A2 only)

9Superpowers (A2 only)

10Option 8A: Health & Human Rights (A2 only)

11Option 8B: Migration & Identity (A2 only)

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