Origin of chemical sediments in Precambrian oceans

The oceans in the Archaean and Proterozoic (3.8 – 0.54 billion years ago) were dominantly anoxic and iron rich. Dissolved silica concentrations were also considerably higher, due to the absence of biological silica sinks such as diatoms and sponges. This unique seawater chemistry is reflected in the Precambrian sedimentary record, which contains abundant iron and silica rich ‘banded iron formation’ (BIF). Experiments simulating BIF deposition in the laboratory can help constrain the origin of chemical sediments, and explore how their deposition resonates through multiple biogeochemical cycles. Combining experimental results with sedimentology can provide new insight into the availability of nutrients during early microbial evolution.