Paleo Flood Debris
NPS Photo by Seth Spoelman
Trip: On 10/31/2006, Rod Horrocks led Seth Spoelman, Erin Niedringhaus, & Bjorn Zindler to the UD survey in the Historic Section where they discovered paleo flood debris in Mud Peel Alley.
Trip Report: We went in to resurvey UD1-6 and survey any side passages off the main survey line. Only 96 feet of the 241 feet was actually resurvey while the rest was new in side passages. All the side passages quickly chocked with mud, except one, at UD12. Looking down a six-inch high bellycrawl, we could see that it opens up and continues on to who knows where. This passage is at the very edge of the cave at this level. Pretty good-looking lead! Unfortunately, the floor and ceiling are all calcified and it's too small for even the smallest caver.
The rest of the UD survey area had been flooded sometime in the past, with organic debris and mud on everything. Because there is calcite popcorn and flowstone on top of the mud, I assume it was from a fairly old flooding event. There are lots of charcoal bits (up to 1 cm in diameter) everywhere in the mud. Water is dripping and seeping everywhere and unlike most of Wind Cave this is a very muddy area. The 1 1/2" thick mud deposit covers a fine sand or silt deposit on the floors. The mud layer easily peels up.
We named this interesting area Mud Peel Alley. We could see a water line in the ceiling fissures that marked the upper flooding limit. In one area, near UD1, we could see where air pockets had been trapped in small domes in the ceiling; kind of cool. The bedrock walls in these pockets were still white, while everything else around them, even above them was brown. We found some graffiti scratched in the mud at UD4 dating from 1934-35. One note said, "Stop, no go". After some debate, we decided the explorer was saying that the lead stopped and didn't go. We found some little tiny spiral snail shells (they are actually hard to see because they are so tiny) that obviously lived for a while on the organic debris underneath a ceiling ledge at UD9. There are also some types of organic fibers/stringers that are mud covered and are hanging down everywhere, especially underneath ledges. They average 1/2-2 inches long. These sway when blown upon. Some of these fibers at UD2 have small calcite popcorn balls on their ends. We got pictures of everything unusual in this area.
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Did You Know?
Winds caused by changes in barometric pressure are what give Wind Cave its name. These winds have been measured at the cave's walk-in entrance at over 70 mph. The winds at the natural entrance of the cave attracted the attention of Native Americans and early settlers.