microscopy

Imaggeo On Monday: The Heart of a Stone

Bernardo Cesare February 14, 2022

The Heart of a Stone. Credit: Bernardo Cesare (distributed via imaggeo.egu.eu)

Heart-shaped glomerocryst (aggregate of phenocrysts) made of plagioclase and pyroxene in a cordierite-bearing dacitic lava from Lipari (Eolie Islands). I study the crustal xenoliths of these lavas to understand the processes accompanying high-temperature metamorphism and crustal melting. But I came across this spectacular glomerocryst and couldn’t help but take a picture! Polarized light pho ...[Read More]

Imaggeo On Monday: Quartz – sericite mylonite, Calamita, Elba

Samuele Papeschi January 17, 2022

Quartz - sericite mylonite, Calamita, Elba . Credit: Samuele Papeschi (distributed via imaggeo.egu.eu)

Concomitant thrusting and magmatism resulted in the development of ductile mylonites in the Calamita Schists, part of the contact aureole of the Late Miocene Porto Azzurro pluton. This mylonite is made up of stretched and recrystallized quartz layers, interlayered with thin sericite-rich levels. Sericite resulted from the crushing of contact-metamorphic minerals such as andalusite, cordierite, and ...[Read More]

Imaggeo On Monday: Blue Olivine in an unusual basalt

Bernardo Cesare September 28, 2020

Blue Olivine in an unusual basalt. Credit: Bernardo Cesare (distributed via imaggeo.egu.eu)

Blue Olivine set in a matrix of pyroxene, magnetite and plagioclase in a basalt collected by the photographer, Bernardo Cesare, on the shore of the Sea of Galilee, Israel. Polarized light photomicrograph. Crossed polarizers and red tint plate. Width c. 2.7 mm. Who may have been throwing this stone a couple millennia ago? Description by Bernardo Cesare, after the description on imaggeo.egu.e ...[Read More]

Imaggeo On Monday: Emoji from meteorites; impact spherule

Seda Özdemir September 14, 2020

Emoji from meteorites; impact spherule. Credit: Seda Özdemir (distributed via imaggeo.egu.eu)

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]