Banded iron formations are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness and extend l
Banded iron formation, Karijini National Park, Western Australia
2.1 billion year old rock from North America showing banded iron formation, displayed in Dresden, Saxony, Germany
Banded iron formation from the Barberton Greenstone Belt, South Africa
Close-up of banded iron formation specimen from Upper Michigan
Cyanobacteria are a group of autotrophic gram-negative bacteria of the phylum Cyanobacteriota that can obtain biological energy via oxygenic photosynthesis. Cyanobacteria originated in a freshwater or
Banded iron formation
…with banded iron formations. Banded iron formations are theorized to have formed in sea water as the result of oxygen production by photosynthetic cyanobacteria. The oxygen combined with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the ocean…
CSIRO Science Image 4203 A bluegreen algae species Cylindrospermum sp under magnification
Cyanobacteria are found almost everywhere. Sea spray containing marine microorganisms, including cyanobacteria, can be swept high into the atmosphere where they become aeroplankton, and can travel the globe before falling back to earth.
Prochlorococcus, an influential marine cyanobacterium which produces much of the world's oxygen
Unicellular and colonial cyanobacteria. (scale bars about 10 μm)