GeoSphere

GeoSphere

Photo of the Week

Photo of the Week

Keepin’ then comin’! This weeks photo is brought to you by Immageo as per usual. It can be found: here

The image was taken by Dmitry Tonkacheev, IGEM RAS, Moscow, Russian Federation.

Dmitry writes, “This is Co-bearing sphalerite, synthesised using gas transport method at 850C looks like the Christmas Tree. Although presented intergrowth of crystals was made in the laboratory, there are some natural samples, that comes from Africa. Green sphalerite from Congo can be used as jewellery.”

I have to chip in that incorporating Co into minerals can often lead to some very unsusual colours. For example, cobaltoan calcite is brilliant, neon pink.

Quartz over Malachite on Cobaltian Calcite

Cobaltoan Calcite from Katanga, Congo. (Source)

Photo of the Week

Photo of the Week

This amazing picture above was taken by Mikhail Varentsov, Lomonosov Moscow State University, Moscow, Russia. It can be found here. Mikhail writes “Melting summer sea ice is separated to pieces by the net of cracks, and their edges have amazing light-blue color, which is in contrast with white ice surface and deep blue sea water. Photo made during NABOS-2015 expedition.”

What this photo really reminds me of is the recent records relating to Arctic sea ice that have been broken. And, sadly, I don’t mean record highs. For a full discussion on Arctic sea ice status check out the Arctic Sea Ice blog. Long story short though this winter has broken all records for loss of Arctic sea ice, following last years record lows. These past two record breaking years are extremely alarming and the repercussions of such low levels of sea ice will be felt throughout the North and will affect the people and animals that rely on the sea ice.

Photo of the Week – Salt Coral

Photo of the Week – Salt Coral

The photo posted below is a really cool one. Interestingly, enough I have been getting into podcasts lately. They are great during my bus ride to and from work every day. One of the podcasts that I like is Neil de Grasse Tyson’s Star Talk Radio. Anyway, the other week Star Talk had a pretty good discussion about salt and the role it has played in developing human history. Check out the episode in two parts here. Arguably as one of the most important economic minerals of all time, although it may not seem so today.

That said, having read the book Sugar, Salt and Fat I would argue that salt retains its title as the most important of all economic minerals even to this very day! Anyone else have an opinion on this?

I digress though. The image below shows an incredible salt concretion on the shore of the hypersaline Dead Sea that has been formed by sea spray that has evaporated creating this magnifcent shape. Despite the title it is not actually coral.

Walking along the shoreline of the Dead Sea, you can find some magnificent objects, like this coral made of salt. Combine that with the beautiful scenery and amazing lighting at dawn and you get this amazing photo. Source - Salt Coral by Zachi Shtain

Walking along the shoreline of the Dead Sea, you can find some magnificent objects, like this coral made of salt. Combine that with the beautiful scenery and amazing lighting at dawn and you get this amazing photo. Source – Salt Coral by Zachi Shtain

Photo of the Week (Approximately)

Photo of the Week (Approximately)

The truly insane photo above shows “Different generations of calcite cements in Late Miocene seep carbonates (Piedmont, Italy; cathodoluminescence microphotograph)”. It was taken by Marcello Natalicchio, University of Hamburg, Hamburg, Germania  – Source.

This photo was taken using a cathodoluminescence microscope which is both a standalone tool or can be an adaptation to a scanning electron microscope. In cathodoluminescence microscopy an electron beam is fired at the sample which causes it to emit light (luminesce). The chemistry of the material being imaged determines the wavelength of the light emitted. Cathodoluminescence microscopy is a very useful tool for visualizing interior features such as fabrics, growth periods or other changes in the crystal interior that are not visible using traditional visible or polarized light microscopy. In the picture above the cathodoluminescence is being used to show the different stages of formation of a calcite cement.

In the geosciences cathodoluminescence microscopy is most frequently used to investigate the growth and deformation history of sedimentary carbonates, the interior structure of fossils, diagenetic processes, growth and dissolution of igneous and metamorphic minerals, and the growth of hydrothermal veins. The reason cathodoluminescence microscopy is so useful is that it allows the interior chemical variability of the sample to be imaged at the microscale without destroying the relationships that exist between the different stages of crystal growth.

I’m not counting Photo of the Week posts any more. The photo updates to the blog will now come whenever I feel like it. To be honest, I’m not sure how often I’ll feel like it. Although, now that daylight savings time has ended that may be more often since getting outside now involves enveloping myself in several layers of fabric. Also, daylight savings time is stupid, and I hate it.

Cheers

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