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 [email protected]. Preview dataset found at https://doi.org/10.23729/161d467b-e35b-49b1-b9c2-e4cf70cdf5a7

Two rock samples from the Isle of Rum, Scotland. Unit11-12 is from the Eastern Layered Series of the ultramafic-mafic layered intrusion on the Isle of Rum, Inner Hebrides, Scotland. Taken on Hallival from the boundary between the Cyclic Units of Unit 11 – Unit 12. Undulatory boundary is marked by a thin chromite seam, with peridotite above and anorthosite below. The aim was to image the 3D geometry of the chromite layer. Peridotite is taken from a plug on Barkeval, within the Eastern Layered Series of the Rum ultramafic-mafic intrusion. Outstanding skeletal olive crystals are evident within the peridotite, and were imaged to reveal their 3D geometry. Fishbone textures are clearly observed, suggesting formation by rapid crystallization, or even quenching, leading to branched morphologies from a central spine. Both samples are from Alan Butcher’s PhD collection. To get this dataset, please contact [email protected]. Preview dataset found at https://doi.org/10.23729/e7157fbd-69d1-44d7-8413-e3a133d0f61f