Banded Iron Formation

A nearly 3-billion-year-old banded iron formation from Canada shows that the atmosphere and ocean once had no oxygen. 

File:Glacially eroded jaspilite banded iron formation outcrop

File:Banded iron formation (Goldman Meadows Formation, Mesoarchean; Atlantic City Iron Mine, South Pass, Wyoming, USA) 1 (30749232474).jpg - Wikimedia Commons

BANDED IRON FORMATIONS (BIFs)

Rise Of Oxygen On Early Earth Linked To Interaction Between Microbes And Minerals

Banded Iron — Articles — Michigan Rockhounds

A: Commonly observed banded iron formation (BIF) alteration stages

Banded Iron Formation - an overview

Generation of banded iron formations by internal dynamics and

Brockman Iron Formation - National Rock Garden

Paleoproterozoic Banded Iron Formation of the Quadrilátero