The Affect of Water on Lehman Caves
NPS PHOTO scott babinowich
Speleologists have theorized that at one time there may have been rising warm or hot water in the cave. This water would only need to be at least one degree warmer than the water in the cave to make a difference chemically. In some places, especially in the Rocky Road section of Lehman Caves, there are ceiling half tubes, evidence of this change in temperature. The ceiling half tubes are though to be places where warmer water entered the cave. Other evidence is the increased metamorphism present in this part of the cave. However, not much research has been done to test this theory. Cracks in the bedrock (joints and faults) have been a major avenue for water (warm or cool) to enter the cave.
NPS PHOTO scott babinowich
Some features in caves show definite directional characteristics. A good example in Lehman Caves is the directional popcorn found in the Rose Trellis Room and the Inscription Room. Only one side of the formations has popcorn, while the other side is undecorated. This is probably because as water moved through the cave, it deposited the popcorn in the eddy behind the formations. It is also possible that this may have happened in an air-filled passage by similar means.
Flowing water caused the scalloping in some parts of the cave. The water (with a little acid in it) moved past the wall from the gradually inclined side towards the steep side of the scallop. As the water moved over the ridge, it swirled down on the backside of the scallop, enlarging it. The erosion was caused by the acid in the water, not gravel and particles. It is possible to determine the speed of the water by measuring the length of the sides and the angle between them. The direction is determined by the steep and gradual sides. The steep side in each pocket is upstream (in other words, on the downstream side of the ridge). It is possible to map flow direction in a cave using scallops. In Lehman Caves, there are places where the scallops in the same room indicate different flow directions. There were probably eddies off the main flow that caused this. The path of the water was generally from the Grand Palace Room towards the cave entrance.
NPS PHOTO SCOTT BABINOWICH
Some formations in Lehman Caves have been redissolved. A good example of this is the formation called the Eagle's Wing in the Lodge Room. The cave drained and some formations grew, then the cave refilled with water some time later. This water dissolved part of the formations. The water drained again, and decoration of the cave continued. It is also possible that some dissolution of formations happens in the air. The moisture in the air that condenses on formations and bedrock may be able to dissolve some calcite. This is most apparent with draperies. Draperies can look heavily corroded and have holes in them. Draperies have a high surface area for water to condense onto and can be very thin, so even a small amount of dissolution would be very noticeable. Some researchers believe that bacteria may play a role in condensation corrosion.