thin section

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

Kristina G Dunkel June 1, 2020

The Grid - A serpentine pseudomorph after carbonate. Credit: Kristina Dunkel (distributed via imaggeo.egu.eu)

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

Charlotte Beasley March 30, 2020

Psychedelic Foraminifera. Credit: Charlotte Beasley (distributed via imaggeo.egu.eu)

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]

Imaggeo on Mondays: Tertiary Flying Saucers

Bernardo Cesare March 2, 2020

Polarized light photomicrograph of a thin section of a fossiliferous limestone from Lake Garda, Italy: Tertiary Flying Saucers. Credit: Bernardo Cesare (distributed via imaggeo.egu.eu)

Besides for the purposes of documenting my research, I like to take photos of rocks under the microscope also because of their aesthetic appeal. It’s an hidden, marvelous world. These flying-saucer-looking objects are in fact the fossil skeletons of a Nummulites (the larger) and a Discocyclina (the one on top left), both belong to the phylum of Foraminifera. These single-celled organisms occupyied ...[Read More]

Imaggeo on Mondays: Cooking crystals in the Earth cauldron

Hazel Gibson February 10, 2020

Cooking crystals in the Earth cauldron. Credit: Julien Leuthold (distributed via imaggeo.egu.eu)

This picture shows a 30 micrometer thick rock section of a gabbro from the Rum Layered Intrusion (Scotland). Large clinopyroxene crystals are enclosed in a foliated fine grained groundmass of plagioclase and olivine. The clinopyroxene core crystallized at an early stage, at 1160°C. They were partly molten at 1200°C during successive hot magma injections and subsequently recrystallized, enclosing h ...[Read More]