This sample is a spectacular example of a banded iron formation or BIF - where by fine grains of iron ore have been deposited in to a shallow water environment and preserving micro-scale depositional events. The significance is that these rocks containing Fe-oxides is that they show there must have been an atmosphere on Earth at these times (Archaean) , otherwise oxides could not form (and did not before these times). This is the so-called great oxygenation event in geological history. Exact location is unknown but it is from South Africa. From the Butcher Collection. To get this dataset, please contact fairdata-pas@gtk.fi. Preview dataset found at https://doi.org/10.23729/161d467b-e35b-49b1-b9c2-e4cf70cdf5a7

2019