January 6, 2023

Geology Word of the Week: K is for Karst

Posted by Evelyn Mervine

Picture of a cave that formed in a karst landscape. Picture taken at Howe Caverns, New York State, by myself.

Several years ago, I used to write a “Geology Word of the Week” post in which I selected a word used by geologists, wrote a definition of the word, and wrote up a post with some information and pictures related to the word. I went through the alphabet in order twice, writing about words starting with letters from A to Z, and then I started a third run through the alphabet, stopping at my last post J is for Jasper back in 2015. Many people enjoyed my geology word posts, but eventually life became too busy for me to keep up the posts. Since 2015 I’ve obtained an M.Sc. degree in Carbon Management, moved countries, changed jobs twice, and had a child… all while working full-time during a global pandemic!  Life is still very busy, but it isn’t quite as busy as it used to be.

For awhile, I’ve been thinking about reviving my weekly geology word posts… and I’ve decided that this year I will do so! I will do my best to post about a geology word every week. I may keep some of the posts a bit shorter than I used to, but I think they will still be informative.

Without further ado, here is the first word for 2023…


def. Karst:

A type of topography or landscape characterized by the dissolution of soluble rocks, such as limestone and dolomite. The dissolution of the rocks leads to the formation of landforms such as sinkholes, caves, and springs. Water is often stored underground in karst landscapes, and thus they can form aquifers that provide sources of water for humans and animals. The sinkholes that form in karst environments are geological hazards that must be monitored and managed.


Here is a great figure showing some typical features of a karst landscape:

Features of a karst landscape. Figure source: https://www.gsi.ie/en-ie/programmes-and-projects/groundwater/activities/understanding-irish-karst/karst-landforms/Pages/default.aspx

Most karst landscapes form in carbonate rocks, such as limestone or dolomite. In these rocks, the dissolution is caused by weak carbonic acid that forms when rainwater picks up carbon dioxide from the atmosphere and soil. In the open spaces of caves that form underground, the carbon dioxide in the water can be released, which causes the formation of speleothems, such as stalactites and stalagmites. If you’ve ever been in a cave with stalactites and stalagmites, then you’ve been in a karst landscape.

Below are a few pictures from Howe Caverns, a limestone cave in New York State that I recently visited with my family. You can visit an underground lake in this cave – and you can even take a boat ride on the lake! If you want to see a karst landscape up close, then I recommend a visit to Howe Caverns or another cave system.

Stalactites forming at Howe Caverns, New York State. Picture by myself.


Speleothems and other cave rocks reflected in an underground river at Howes Caverns, New York State. Picture by myself.


Gorgeous speleothems at Howe Caverns, New York State. Picture by myself.


Pictures of the boats you can take on the underground lake at Howe Caverns, New York State. Picture by myself.


That’s all for this week’s word. Stay tuned for next week!