The Križna jama Cave on the east side of the periodic Cerknica Lake in Slovenia is an underground karstic cave primarily famous as a rich site of bones of the extinct cave bear, Ursus speleus. The eight kilometer long cave is full of stalagmites and stalactites (sometimes called drip-stone decorations) and also boasts 50 underground …[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]
Sometimes in order to test a theory about how processes work below the surface of the Earth, scientists need to recreate minerals found in very specific circumstances. This photograph was taken through a binocular microscope during a critical step of the creation of artificial peridotite: extraction of the artificial peridotite from its gold capsule. The …[Read More]
“Crazy Lace” is an agate collected in Mexico, which offers great opportunities for aesthetic photomicrography. Here we see the common arrangement of fibers of chalcedony (microcrystalline quartz) in parallel bands alternating with black thin layers of Fe oxides. Polarized light photomicrograph, crossed polarizers and red tint plate. width 5.4 mm. Sample kindly provided by Denise …[Read More]
At the edge of the Greenland Ice Sheet, surface melt releases old layers of dust, that have travelled thousands of years into the ice. Under sunny weather, the dust heats up with radiation, melts the ice underneath, and thus accumulates in tiny potholes and meltwater creeks. However, this photo was taken after a rainy day. …[Read More]
Annual ridges and troughs (called wave ogives) are formed as the ice of the Gates Glacier (in Alaska’s Wrangell Mountains) flows through a steep icefall. Down-glacier, as the ice melts, the rushing meltwater is funnelled into streams, carving ice canyons as it flows, but ultimately directed by these topographic constraints. Description by Allen Pope, …[Read More]
High altitude karstic environments often preserve permanent ice deposits within caves, representing a lesser-known portion of the cryosphere. Despite being not so widespread and easily reachable as mountain glaciers and ice caps, ice-caves preserve a great deal of information about past environmental changes and paleoclimatic evolution. Since one of their main characteristics is to have …[Read More]
Aerial view of the Chuquicamata copper mine in Northern Chile. This is the largest open pit copper mine in the world by volume (at the time of sharing). At this location the copper and molybdenum is extracted from a porphyry deposit that was formed beneath a volcano in the Andean subduction zone. Description by …[Read More]
The Mutnovsky Geothermal Power Plant is the largest geothermal power plant in Russia (the time of writing). It is located near to volcanic mountain Mutnovsky at altitude of 800 m and has a capacity of 50 MW. The Mutnovsky Geothermal Power Plant has resolved the problem of raising the stability of the power supply for …[Read More]
The image shows a northern hemispheric summer day of the year 2012. One can see an impressive north Atlantic cyclone, a cloud free Mediterranean Sea, Saharan dust north of the Canary Islands, and cumulus fields near the coast of Namibia and Angola. The image was taken at June 28, 2012 09:00 UTC from the MSG …[Read More]
