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 photomicrograph. Crossed …[Read More]
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, …[Read More]
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 …[Read More]
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 …[Read More]
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 …[Read More]
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 …[Read More]
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 …[Read More]
Throughout October and November, the world of (Earth science) Twitter was taken by storm: Day after day, Eddie Dempsey (a lecturer at the University of Hull, and @Tectonictweets for those of you more familair with his Twitter handle) pitted minerals against each other, in a knock out style popular contest. The aim? To see which …[Read More]
The impressive Zagros Orogeny, as seen from a bird’s-eye view, has featured on Imaggeo on Monday’s blog posts a few times recently. From its fluvial dissection features, through to a false colour LANDSAT 7 image which reveals a velociraptor hiding among fold and thrusts, we’ve looked at the broad scale structures which shape the Zagros …[Read More]
