Limestone: Caves and Caverns

Glenwood Springs and the Colorado River as seen from the elevation of the cave entrance

Last year, my dad took his grandkids and me to visit a cavern out in Glenwood Springs, Colorado.  It was already an exciting adventure before we got anywhere near the cave’s mouth because to get to it, you have to ride up a cable car almost to the top of one of the Rocky mountains.  You do walk down a little to get into and through the caves, but they are still at an elevation of 7,100 ft [2164m].

Looking around today I found this isn’t the only cave system up in the Rockies, there’s another one near Pike’s Peak at the same height.

Great Basin National Park in Nevada has a page that mentions its high caves, called Alpine caves.  Some of them are plugged with old snow and are up at a height of 9,000 to 11,200 ft [2743m to 3413m].  Many of these high caves form along natural breaks in the rock layers, but the highest one in Nevada, called High Pit, is just an ordinary dissolved cave (which I’ll explain in a minute).

Plateaus in the Puna Region, Ayacucho, Peru

Turns out these are nowhere near the world record for the highest caves in the world (remember, this list is in meters, so 6,645m=21,802ft!).  Although these super high ones could be formed by glacial action rather than the usual liquid water, there are still some very impressive heights for limestone caves found in the Andes at over 4,500m [14,765ft].

Another unexpected place to find caves, complete with stalactites and other “decorations“, is in the desert.  There are quite a number of these caves on the Arabian Peninsula.  Some of these are even growing more formations in today’s climate!

OK, now that we know about this, let’s see how caverns form.  Last time I talked about Karst landscapes.  These are all formed in Limestone or variously named forms of Calcium Carbonate rocks.  If you can see the sky above, you call these Karst sinkholes, but if you have to crawl into them out of the sunlight, they are caves!  There are a few other caves formed in salt layers or gypsum that also dissolved by water.  The only other caves are formed by wave or glacial action or from lava tubes.

Remember, limestone will dissolve in water, especially water mixed with Carbon dioxide forming Carbonic acid.  Most websites will tell you this acid forms slowly under normal circumstances, which is true, but there was a time when very unusual things were happening, wasn’t there?

Satellite photograph of the Arabian Desert

We know most caves were hollowed out when the water level was above the level of the cave.  But when would that have been true at the tops of the mountains or in deserts?  When the fountains of the great deep were letting out a bunch of Carbonated water, you had limestone rapidly laid down and then hollowed out in places.  I haven’t covered how soft newly formed rocks would be, but since limestone really does equal Cement, you already know what it was like for a short time during one extraordinary year.

Then, to get all the beautiful decorations we pay money to see in caves, you have the much slower process of water flowing over and through these caverns.  Here’s where what we believe about earth’s past really come in.  If we think the world has had about the same climate for the last several million years, you would assume the tufa laid down in caves is a 100,000 years or more old.  But if we assume there was a whole bunch more rain and snow falling just a few 1,000 years ago, you can have the same formations easily fit into a much shorter timeline.

Once again, it all comes down to one’s Worldview!

Tremble, thou earth, at the presence of the Lord, at the presence of the God of Jacob;
Which turned the rock into a standing water, the flint into a fountain of waters. Psalm 114:7,8

To follow a guy exploring a wild cave in Colorado at 12,000ft [3660m] with some interesting pictures, check out THIS PAGE