Logbook entry: Cathedral-Mammoth sampling trip (2016-12-09) at Cathedral - Mammoth Cave System
About happenings on Dec. 9, 2016, Tehnuka Ilanko wrote:
G-411 were lucky enough to have Aaron come with us for a sampling trip to Cathedral-Mammoth. We drove out around 10 am(?) on a beautiful calm day. The route was good with a bit of sastrugi. I collected some clean air outside and (hopefully) upwind. Tom set a rope with something like six pickets and we rappelled into Mammoth. The entrance had a small ledge near the top then was fairly straight.
We wandered around Mammoth first, with a temperature probe and CO2 monitors (the G-411 Testo device with a wand, and Aaron's more sophisticated BFC multigas monitor), looking for vents. The big vent Aaron remembered was still there but we couldn't feel any airflow out, or measure anything. The Testo consistently read in the high 4000s of ppm with small increases - e.g. up towards the back left of Mammoth - that couldn't be traced to a vent. Tobias tried digging out a hole near the back of the cave and was considering placing a probe here but again, CO2 looked pretty similar in the hole to outside it.
Based on Aaron's knowledge of possible vents, we decided to see if we could access Cathedral. We looped back to the entrance and on to the connection between the caves, which was open. There were warm air vents close to here. We set up a probe at one, Cathedral A, which was at 15C and about 5000 ppm of CO2 on the Testo, and continued towards the Cathedral chamber. On the way we passed some cold vents on the roof, where I later took a bag and vials for CO2 carbon isotope analyses. At the rocky slope leading into Cathedral, we came across several vents. Tobias chose one that was off to the side and about 12C, and we called this Cathedral B. We admired the crystals in Cathedral and took some photos. Aaron took a lot more photos for his structure from motion work. I also collected some cave air in a bag and vials to see if we could find mixing between the cold vents, outside air, cave air, and warm vents.
Once we had picked up all our samples we headed out and up. Some reversing was required to avoid driving over the cave. There was plume snow, and we had missed the nice weather while underground.