GeoLog

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Colour deficient vision and the geosciences; just another way of looking at things

Colour deficient vision and the geosciences; just another way of looking at things

Like a reasonably large proportion of the population, I have colour vision deficiency (also known as colour deficient vision or colourblindness). I’m not going to get into the technical aspects of what this is like as they are covered well here and here, and you can do an Ishihara test, and other tests here, to check your own vision. The other reason I’m not going to discuss the technicalities of ...[Read More]

Imaggeo On Monday: Emoji from meteorites; impact spherule

Imaggeo On Monday: Emoji from meteorites; impact spherule

This is a crossed polarized light photomicrograph of an impact spherule; a small mineralisation made when a meteorite hits the Earth and melts the rock at the point of impact, from Barberton Greenstone Belt, in South Africa. These spherules are the only remnants of Early Earth’s meteorite impact history, from between of 3.2 and 3.5 billion years ago. In this photo you can see the K-feldspar ...[Read More]

Imaggeo on Mondays: The Grid – A serpentine pseudomorph after carbonate

Imaggeo on Mondays: The Grid – A serpentine pseudomorph after carbonate

The structures in this photo might look three-dimensional, but they are completely flat. It is a photo of a polished thinsection of a rock, taken through a petrographic microscope under cross-polarized light. The width of the image is just 2 mm. The brownish mineral around the edges is carbonate, the white to grey mineral in the centre is serpentine, a water-bearing silicate mineral. The different ...[Read More]

Imaggeo On Mondays: Psychedelic Foraminifera

Imaggeo On Mondays: Psychedelic Foraminifera

This is a transmitted light microscope image of a thin section – a 50-micron thick sliver of rock. This sample was collected from Jebel Hafit, a mountain which straddles the United Arab Emirates and Oman border. Jebel Hafit is approximately 900 m high and is made up of Eocene to Miocene age carbonate rocks which were mainly deposited in a shallow water, tropical setting. More specifically, this im ...[Read More]