Oxygen isotope perspective on crustal evolution on early Earth: A record of Precambrian shales with emphasis on Paleoproterozoic glaciations and Great Oxygenation Event

- Temporally increasing δ18O values of shales reflect progressive crustal maturation and sequestration of weathering products.
- This pattern is different from the coeval trends of carbonates and cherts.
- δ18O rises and falls are linked to the supercontinent cycle.
- Lowest δ18O and δD shales associated with Paleoproterozoic Snowball glaciations.
- There is no difference in δ18O values in shales deposited before and after the GOE.