Application of recently developed silicon isotope (δ30Si) proxies to Archean chemical weathering
Using what we know from modern continental systems, and the way that silicon behaves, we can understand how silicon was delivered to the ocean in the ancient past.
In modern continental systems, silicon (Si) is taken from the continental crust during chemical weathering and erosion. This silicon is then delivered to the ocean. Today, organisms such as diatoms take the silicon out of the ocean and use it to make their cell walls.
In the geologic record, organisms that used silicon did not exist. Instead, the silicon that was delivered to the ocean from chemical weathering of the continents precipitated out of the ocean to form iron-silica deposits, or banded iron formation. In the rock record, such Fe-Si deposits, called Superior-type BIF, formed in this depositional setting are often found associated other sedimentary rocks (sandstone, shale, carbonate, etc.).
To decipher the role of silicon in the early ocean, I am interested in using geochemical and isotopic tools to determine sources and sinks of silicon and quantify quartz deposition mechanisms throughout the Precambrian.
Undergraduate Earth and Environmental Sciences major Stephen Hanson ha…