The World's Most Unreal Geological Formations

Our planet has built some pretty cool stuff over the past 4+ billion years. The mechanisms it employs to push up and tear down itself are endlessly fascinating. Layers of sediment are laid by eruption or erosion only to be shoved, smashed, pressed, folded, uplifted and eroded again. Minerals react and interact with each other chemically and metamorphically, creating unreal shapes and amazing colors and textures.  Most of the time a mountain looks like other mountains or a rock looks like any other rock, but sometimes factors conspire to create the most fantastical things... things you can't believe occurred on their own. Things that seem to flaunt physics or nature itself. This is a list of the most amazing geologic formations on earth. Vote up the ones you think are the most spectacular, the most insane... the most unreal.

Photo: Analise Dubner

  • 1
    221 VOTES

    Ausangate Rainbow Mountains

    Deformation, Mineralogy and Erosion

    Thanks to the intense volcanism of the region, the Ausangate Rainbow Mountains of Peru are one of the most astonishing geologic marvels on Earth. The Andes mountains are an incredibly complex chain of mountains that formed by the subduction of the Nazca plate under the South American plate. Like most subduction zones, it produced an enormous amount of volcanic activity and rare minerology. The rainbow itself is due to the environmental conditions and mineralogy. Iron oxides, goethite, oxidized limonite, iron sulphide and chlorite all paint the hillsides with brilliant colors while the twisting shapes are entirely due to the exposure of the deformation of the mountains from the uplifting. It is easily one of the wonders of the geologic world.

    221 votes
  • Volcanism & Bacteria

    Located in Yellowstone National Park, the Grand Prismatic Spring is another fantastical creation of volcanism - like many of the wonders in the park. It is a hot spring, formed when heated water comes up through cracks in the Earth's crust. The water cycles through rising and falling - heating and cooling - and the constant cycle creates rings of distinct temperatures.  While water at the center of the spring is too hot to sustain most life at 189 degrees Fahrenheit, as it spreads out it cools and each ring of varying temperature hosts a different type of bacteria. And each type of bacteria produces a different color. The water at the center results from the inherent blue of the water (because of the scattering of blue wavelengths, the same reason the ocean appears blue) because of its depth and sterility.

    186 votes
  • 3
    200 VOTES

    The Wave

    The Wave
    Photo: Gb11111 / Wikimedia Commons / Public Domain

    Deformation and Erosion

    Located in the spectacular Coyote Buttes on the border of Utah and Arizona, The Wave is a bucket list item for photographers. Believe it or not, the formation is caused almost entirely by wind. The wavy layers themselves were formed in ancient sand dunes, the different layers representing the deposition of sand grains of slightly different sizes. Their twisting orientations are representative of the direction of the prevailing winds of their time.

    The Wave exposes deformed laminae within the Navajo Sandstone that was laid down during the Jurassic. Fantastically, these laminae were deformed before to the lithification of the sand to form sandstone and, judging from their physical characteristics, this deformation likely represents the trampling and churning of these sands by dinosaurs! How cool is that? 

    200 votes
  • 4
    180 VOTES

    Cave Of The Crystals

    Cave Of The Crystals
    Photo: Alexander Van Driessche / Wikimedia Commons / CC-BY 3.0

    Crystalization

    Found in Chihuahua, Mexico, the Cave of the Crystals is a cavern connected to the lead, zinc and silver Naica Mine. Discovered in 2000, the cave is a true fantasy land that rivals any science fiction book cover illustrator's wildest flight of fancy. It is no stretch to say that it is one of the most spectacular mineralogical discoveries ever made.

    Giant, elongate, selenite mega crystals, the largest ever found on Earth, sprout and crisscross from the ground and walls - some are over a meter thick! The crystals formed when magma from an underground chamber (that still sits there today) heated the ground water which was saturated with sulfide ions. Cooler surface water contacted the mineral saturated heated water, but because the oxygenated cold water and the mineral saturated hot water were different densities the two did not mix. Instead the cooler water slowly diffused.

    The chemical reaction created a hydrated sulfate gypsum that crystallized at a very slow rate... over 500,000 years! It was this very slow mix that allowed these crystals to form into the enormous size we see today. Don't think you will be able to put this cave on your bucket list, however. Its temperature is 122 degrees Fahrenheit and the humidity is 100%. Humans can only survive a few minutes at a time in the chamber. It can only be explored with specially designed, protective gear that ups the amount of time a person can survive inside to an hour.

    180 votes
  • 5
    141 VOTES

    Devil's Tower

    Basaltic Columns

    Found in Bear Lodge Mountains of Wyoming, Devils Tower rises sharply and dramatically upwards to a height of 867 feet tall from base to summit. It got its name in 1875 when Colonel Richard Dodge misinterpreted a native name for the feature to mean "Bad God's Tower". The Natives in the area actually called it a variation on Bear's House or Bear's Lodge.

    The tower is a great example of volcanic intrusion.  It began its formation 56 to 66 million years ago when the Rocky Mountains were uplifted. Magma rose up through the crust and intruded into the existing sedimentary rock layers that had accumulated 225 millions years previous when the area was a vast shallow sea. While geologists agree that the tower is a volcanic intrusion, they don't agree on exactly how the process took place. It was first thought to be the eroded remnant of a laccolith (a large mass of igneous rock that intrudes sedimentary beds without reaching the surface), but other theories posit that it is a volcanic plug or the neck of an extinct volcano.

    The columnar structures you see making up the sides were formed through the same process as the Giant's Causeway, cooling magma shrinks and cracks form at a 120 degree angle creating hexagonal columns. Devil's Tower looks solid and imposing, but erosion continues to this day and will keep eroding the base away, exposing more and more of the intrusion.

    141 votes
  • 6
    155 VOTES

    Slot Canyon

    While there are many, many extraordinary slot canyons out there in the world, most would say that Antelope Canyon takes first place in pure, amazing beauty. Found in Arizona, this canyon was formed by the erosion of 191-174 million year old Navajo sandstone and primarily carved by flash flooding. When it rains over these sandstone desert regions, water rushes and collects and merges and gains speed on rocky sandstone basins without any earth to soak it up or slow it down. Each time a new wall of water mixed with debris rushes down these narrow slots, it gouges sand off the walls of the canyon. The color comes from the iron oxides deposited in the sandstone in varying amounts and when the light shines down through the top of the slot, the colors and stripes of the walls make Antelope one of the most amazing geologic sights in the world.

    155 votes