Carroll Cave Survey Trip Report
Area Mapped: Upper Thunder by the UL3 Maze
Team: Bob Lerch, book and sketch; Jessie Bebb, lead tape, backsight, and inventory; Robert Kramer, tape and foresight.
Team Leader: Bob Lerch
Time In: 12:30p Time Out: 2:30a Duration: 14.0 hours
Our goal was to push the Upper Thunder main passage survey and tie-in all the points at which the UL3 Maze intersects main passage – all four of them!
Robert had not been in the cave for 25 years, and he had never seen any of the territory we were heading through today. Of course, we went a bit slower than normal in order to point out features of the cave to Robert. After about 1 hour and 25 minutes we arrived at the start of our days work, station U104.
U104 is located about where the first and lowest stream level of UL3 enters main passage on the left, and the Round Room is up and to the right. This first intersection with the maze appears to be the majority of the water draining this area of the cave, but it is a relative trickle compared to Thunder River. We mapped through some waist-deep stream passage for the first shot, and we decided to leave the grimmest low meander for another day. The stream was running about twice that of baseflow, and the air-space was too low without wet suits for surveying. By-passing the meander, we got on to dry passage and reeled off a long shot that intersected the second UL3 entrance. The maze enters at the very top of the passage and is easily overlooked. The main passage in this area is typical for Upper Thunder. It is characterized by very wide passage (80’-120’) that slopes downward over a series of ceiling and floor ledges all the way to the stream. Along a cross-section, ceiling heights vary from 2’ to 30’ in this area, with the main traffic routes following the tallest ceiling channel. The highest ledges typically have a layer of dolomite sand (i.e., grains of dolomite that have fallen off the ceiling) over clay with bat bones scattered throughout. The bones appear to be mainly wing bones based on their length (1.5”-2”).
After two more shots, we intersected the 3rd UL3 entrance. There was a small overflow channel with a trickle of flow coming from two pools right at the intersection of the maze with the main passage. The main passage is nearly 120’ wide at this point. We stopped for some needed nourishment, and then pushed on for several more long shots. We ended where the 4th UL3 entrance, “Boner Balcony”, overlooks the stream in the main passage. The balcony got its name because some cavers, having gotten turned around in the maze, came upon the balcony for the first time and thought they had discovered a new river. We mapped 489’ of very difficult-to-sketch passage. Jessie and Robert managed to amuse themselves in the long intervals between shots by looking around the maze and taking detailed inventory notes. I appreciated their patience in this mind-bending stuff.