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Sorry for the second reply, but just for the technically curious, I found photos: The government site says these stones are calcite, flowstone, round bubbly ro

Sorry for the second reply, but just for the technically curious, I found photos: The government site says these stones are calcite, flowstone, round bubbly rocks. (formed in a same/similar manner as stalagmites?) Almost all the rocks in this cave are calcite. (I looked through a number of them on this site) [0] This appears to be the thick layer of rock that I was told formed rather quickly. [1] This is a clear picture, and it looks like large crystal growth? Which would explain the difference from slow stalagmite/stalactite growth? [3] A detailed description, I honestly don't get all the chemistry/geology enough, but I have to trust they are being consistent. :P [4] [0] https://www.usgs.gov/media/images/flowstone-formations-jewel-cave https://www.usgs.gov/media/images/flowstone-formations-jewel... [1] https://www.usgs.gov/media/images/cross-section-calcite-crystal-covering-jewel-cave https://www.usgs.gov/media/images/cross-section-calcite-crys... [3] https://media-cdn.tripadvisor.com/media/photo-s/04/53/d9/bd/jewel-cave-national-monument.jpg https://media-cdn.tripadvisor.com/media/photo-s/04/53/d9/bd/... [4] https://www.nps.gov/jeca/learn/nature/geology-of-jewel-cave.htm https://www.nps.gov/jeca/learn/nature/geology-of-jewel-cave....

jofer 9y ago
Oh, yeah! Jewel Cave is a bit unique in this regard. There's a lot of sparry calcite (large, well-formed crystals) inside the cave. The difference is in the size and shape of the crystals. Large crystals like that can only form when they have lots of room to grow (i.e. when everything is underwater). Those formed while the cave was flooded with water that was over-saturated with calcium carbonate. The rate of growth of a calcite crystal is a lot faster (inches per decade) under those conditions. The speleothems that are forming today grow slower (inches per century) because they're precipitating from a very thin layer/drip of water that only becomes saturated when it starts to evaporate or flow differently. Both processes are very rapid in geologic terms, but there's a significant difference in rate between the two.

jofer 9y ago

Oh, yeah! Jewel Cave is a bit unique in this regard. There's a lot of sparry calcite (large, well-formed crystals) inside the cave. The difference is in the size and shape of the crystals. Large crystals like that can only form when they have lots of room to grow (i.e. when everything is underwater). Those formed while the cave was flooded with water that was over-saturated with calcium carbonate. The rate of growth of a calcite crystal is a lot faster (inches per decade) under those conditions. The speleothems that are forming today grow slower (inches per century) because they're precipitating from a very thin layer/drip of water that only becomes saturated when it starts to evaporate or flow differently. Both processes are very rapid in geologic terms, but there's a significant difference in rate between the two.