Figure 2: Summary of CeSN/Ce*SN and Fe-speciation data for nine localities.
From: Low-oxygen waters limited habitable space for early animals
The location of nine sections within the Kuibis and Schwarzrand Subgroups of the Nama Group is shown on a simplified geological map of Namibia52,53,55,57 (a), as well as on a schematic cross-section, indicating average relative water depth (b). The numbers along the basin profile relate to the relative position of each section as numbered in c. FeHR/FeT data for each location is shown for carbonate and siliciclastic rocks5, alongside 
data, screened for carbonate rocks showing seawater REY patterns (for example, molar Y/Ho>67) (c). Blue FeHR/FeT data indicate where Fe speciation predicts oxic conditions5 and positive Ce anomalies indicate where waters are interpreted to have been manganous. The presence of in situ biota is noted by grey lines5.
