A widespread positive δ13Ccarb anomaly at around 2.33–2.06 Ga on the Fennoscandian Shield: a paradox?

ABSTRACT Carbon isotope measurements carried out on 201 carbonate samples from the early Proterozoic of the Kola Peninsula, N. Karelia and Norway yield δ 13 C (PDB) spanning ‐ 20.5% to + 11%. A general δ 13 C secular trend shows that prior to 2.33 Ga values are typically ‘normal’ marine, averaging a... View More