Tufa

Image source: http://russbishop.photoshelter.com/image/I0000O12sX0mq9bU

Material: Limestone

Process: Tufa is a type of limestone that is formed when calcium-rich spring water mixes with the carbonate-rich Mono Lake water and precipitates around the spring. The towers grow underneath the waters surface. Sand Tufa is formed in more sandy regions of the lake near the shore. When the lake level dropped these tufa were exposed to the elements, the wind blew away the remaining sand, leaving these unique formations behind.

This is interesting because it has been under the water and can only be seen now because of environmental changes. The shapes are very interesting and complex.

Matilda

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Wind Erosion

Árbol de Piedra

Altiplano, Bolivia
Photo by: Arbol de Piedra

Wind erosion is when wind removes fine-grained particles by turbulent movements. This phenomenon take place in places called deflation zones, almost half of the earths desert surfaces are stony deflation zones and they have different appearance due to the different movements of the wind. You can find “blowout formations”, “desert varnish”, “vardangs” and so on. What is interesting is that it is a trace of the negative of movements in contrast to stalactites formation where you actually follow the movements.

Cave formation

Left:Demonstration of drip stone formation in a lab.
https://en.wikipedia.org/wiki/Stalactite

Right:
Carlsbad Caverns National Park, New mexico

Stalactite is a type of formation that hangs from the ceiling of caves, hot springs, or man made structures (bridges and mine). Stalactites can be composed of many different materials such as lava, minerals, mud, water, sand etc. When a stalactite meets the floor it is called stalagmite.

Any material, which can dissolve, hanged in suspension is capable being formed as a stalactite. I found this phenomenon very interesting since it is very common and demonstrates a movement and I also think one could experiment with it further on.