Archive for the ‘Caves’ category

Lava Tubes on the Moon!

November 25, 2009

Image credit: JAXA/SELENE

Ever wonder how astronauts on the moon are going to avoid deadly space radiation? One option is to live in caves, and luckily the Kaguya team has found one! Read more about it in my article over at Universe Today.

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Massive Crystals: The coolest thing I’ve ever seen.

October 21, 2008

Really, that’s all I said for like 5 minutes after seeing this picture for the first time:

Those are PEOPLE, for scale. Here’s another pic, just to put you in a little more awe:

These are the largest crystals yet to be found on Earth, with some reaching over 30 feet in length! As reported in NG, The Cueva de los Cristales is located 1000 feet below ground in the Chihuahua desert, and was discovered in 2000 during drilling for a nearby lead and silver mine. The cave is excrutiatingly hot and humid – 112 degrees F and 90-100% humidity! The cave is so hot, that suiting up to go inside is sort of like doing a reverse space walk. Everyone has to wear ice packs, full body insulation, and a respirator mask in the cave.

The reason the cave is so hot is also part of the reason the crystals formed here. The cave lies above a magma resovoir, which heated the local groundwater. Until 1985, when the mining operation lowered the local water table to extend the mine, the cave was completely submerged in this super heated groundwater. As the magma cooled, the water in the cave cooled enough to deposit selenite, a form of gypsum. The environment in this cave was stable enough over hundreds of thousands of years that the selenite crystals were able to continue growing uninterrupted.

We know there are massive gypsum deposits on Mars (ref: my thesis!), and we know that Mars has been much more tectonically stable than the Earth, so who knows? We might find crystal deposits on Mars to dwarf Cueva de los Cristales. Everything’s bigger on Mars anyway, right?

How old is the Grand Canyon? The speleologist knows…

March 7, 2008

I learned a new word in Science this week:
Speleology: the study or exploration of caves. Think “spelunking.”

The word was in an article by UNM geologists Polyak et al. on a new age estimate of the Grand Canyon. For many years now, geologists have estimated the formation time of the Canyon at around 6 million years. The new study puts the age at close to 20 million. This may sound slow, but it’s still wicked fast on geologic times. Especially when you consider that the Canyon is ~1 mile deep!

The reason I liked this study, aside from the use of words like speleology and mammillary (yes, mammillary), is the method they used to date the Canyon: by dating groundwater deposits in caves! The round deposits, called cave mammillaries (for obvious reasons), form in caves below the water table, and are made of calcite and gypsum. Check out these mammillaries (I’m not trying to be obscene, really):

Underwater cave mammillaries!

By dating the minerals in the mammillaries, the geologists were able to track the river water level in the canyon over time, and up and down the Canyon. They found that the erosion rate in the Canyon was much higher toward the beginning of its formation, and that it didn’t all form at once. So, how did it form, you ask? Here’s the basic idea behind their hypothesis:
1) The Colorado Plateau was tectonically uplifted ~20 million years ago
2) The uplift caused incision of the western Grand Canyon by a smaller stream
3) About 6 million years ago, the western Grand Canyon broke through to the Colorado
4) The shallower eastern Canyon was rapidly cut by the Colorado River
5) Erosion rates slowed to what they are today (75 meters per million years)

The final result:
Grand Canyon

All this from minerals in caves! Maybe one day we’ll be able to do some speleology on Mars….