Vivianite Notes

Hurowitz and many others (2025) discuss organic carbon bearing mudstones on Mars that have bluish nodules. The analysis of the reaction fronts on the nodules indicated ferrous iron phosphate and sulfide minerals with the blue possibly being vivianite. Vivianite nodules are known to form in fresh water and marine settings as a by-product of low-temperature microbially mediated Fe-reduction reactions. Hence, these nodules on Mars have generated intense interest. Hurowitz and many others (2025) do note that there are alternative explanations, but the biotic explanation is intriguing. Kawahara and others (2022) note that there are non biological processes for similar appearing nodules. So at that this point nothing definitive -- such is science. At some future date this rocks may be subject to more sophisticated analyses. 

 

My first encounter with the mineral was in regards to phosphorus removal from waste water or stormwater. There were some clever chemists trying to come up with solutions to minimize nutrient loading in lakes fro waste water. 

A while back I did some research based on coincidental inquiries about sources of blue coloration. One inquiry was regarding possible sources of blue coloration used on canoes by Salish Sea peoples prior to European contact. I was asked if I knew of any vivianite depsoits in the area. The other inquiry was similar but came from an art supplier who thought I might have some insight regarding vivianite sources. I did find some references of pre European trading associated with a site in Alaska.

Vivianite Fe(II)3(PO4)2.8H2O shows up around buried organic material. It also shows up in sewage facilities. A local source for the Salish might have been along clay rich tidal sloughs where lots of wood would have been buried. 

Another potential source could be clay rich Bellingham Glacial Marine Drift that has remained saturated and is in close contact with buried organic material. The saturated drift is already blue from the iron and magnesium not being oxidized. The contact with buried wood would provide the phosphate to have added blue color, but I have not observed any vivianite features when excavating or drilling into the local glacial marine drift.

   

It is my understanding that in finishing cedar canoes the wood would be rubbed with wet clay. I do wonder if some vivianite would precipitate during processing of the bluish clay with the organic material of the canoe thus fixing the iron with microscopic vivianite. That is if you took the very wet and very soft blue glacial drift out of a bank and then mixted it with organic material the vivianite would form within the clay mix and stop the oxidation of the iron that is present and instead create the iron/phosphate oxide vivianite and thus "fix" the blue color. Even rubbing the blue clay on the wood might cause the same reaction.