On a lighter note, the geology of the area is rather interesting. The park is on the fringes of the basin and range province, part of the Great Basin Desert, and at the southern end of the active Cascade Arc. It lies on the slope of the Medicine Lake Volcano, the largest (by volume) of the cascade volcanoes. Mt. Shasta is the most voluminous of the big cones, but lavas from Medicine Lake are estimated to fill at least 140 cubic miles. It is a large basaltic shield volcano with numerous cinder cones and basalt floes along its slopes, perfect conditions for lava tubes. Beneath the recent Cascade volcanism is the southern extent of some of the Columbia River Basalt Flows, namely Steens Mountain Basalt and Painted Mountain Basalt flows.
Caves in the park include the infamous Catacombs Cave, a maze of well over 6,000 feet of passages ranging from room size to narrow crawl tubes, and the small Mushpot Cave, which has been developed for easy access and is lit on the inside to demonstrate various features of lava tubes and their formation. It is very cool to go from a completely dark cave like Labyrinth and into the lit and developed cave that exposes all the features that were hidden by the abysmal darkness. There are several monitored ice caves, but due to climate change, ice is rapidly disappearing from them.
|Lavacicles form as the lava forming the ceiling drips down|
|Lavacicles and drips in Mushpot Cave.|
|Crisp lava drips in Labyrinth Cave.|
|Often, multiple lava flows flowed through any given lava tube. This|
leaves behind features like these that show the level of various flows.
In this cave, at this spot, we counted five separate additional flows!
|Cool lava cauliflowers. I'm not really sure how they form, but they're neat.|