Going Deep
Sunday
Solution caves are the most common type of cave, and are effectively caverns in which the rock has been dissolved. This typically happens when rainwater, made slightly acidic by CO2 in the atmosphere (and sometimes the soil it filters through) slowly dissolves the limestone, dolomite, gypsum, or salt rock it touches, creating caverns of all shapes and sizes.
Monday
Glacier caves form when glacier meltwater drains through vertical crevasses, then flows out of the mouth of the glacier. These caves can be especially beautiful to behold, yet dangerous to explore.
Tuesday
Sea caves (aka littoral caves) and eolian caves are created by erosion from waves and wind, respectively. These caves tend to be comparitively shallow.
Wednesday
Talus caves (aka boulder caves) are made in the spaces between piled-up boulders, usually on the side of mountains. They’re typically small, though there are some notable exceptions of these caves going over a kilometer.
Thursday
Lava tubes are caves formed when molten lava flowing from a volcano creates a moving stream, then the top layer of the molten rock cools and hardens while liquid lava continues to flow beneath it. When the sides have hardened and the liquid rock has then drained out, what remains is a tube, sometimes large enough for humans to explore.
Friday
South Africa’s 139 meter-deep Wonderwerk Cave, itself part of a natural rock formation 2.4 billion years old, contains evidence that early humans lived inside of it 2 million years ago and frequently since, though “modern” humans only rediscovered it in 1940.
Saturday
Although many creatures like to spend time in caves, troglobites are a category of creatures which live only in caves and are especially adapted to do so. They tend to have excellent hearing, smell, and touch, but are often blind or nearly so.