05 August 2008

Cave of the Shrunken Skull and Lessons Learned on Expedition

Originally drafted 01 August 2008

Mapping Cueva de Chulacao. Credit: Dan Ruby.

We went to “Cueva de Roberto.” This is a lesson learned the hard way. After discussions with Roberto a few days prior, we were under the impression that this was a separate cave. Well, perhaps my Spanish isn’t as good as I would have liked, or perhaps Roberto had not explored this cave to the extent that we had thought. We were really looking forward to assessing this cave as a potential study site – and the fact this was close to Cueva Traga Luz Grande was another bonus.

Pete, Lynn and I were in the process of setting bolts and other pro to make a 70 foot rappel into this new cave – when John walked into the cave and said the mapping team believed we were in another entrance for Traga Luz Grande.

John, Christina and Dan entered Traga Luz Grande to take a side passage to see if the cave connected. Unfortunately, the cave was one and “Cueva de Roberto no existe.” Cueva de Roberto was actually part of Traga Luz Grande. This was a major disappointment to the entire team.

When Pete, Roberto and I deployed sensors in Traga Luz Grande, we were not verifying the map, and we totally missed this side passage. The fact that we missed this side passage really stung, and it was a good lesson in humility.

Dan pushing passage in Traga Luz Grande. Credit: Christina Colpitts.

The other day when we finished deploying sensors in Traga Luz Grande, I felt really good about getting this big cave done. I think this just goes to show that one can try to do the best job possible, and then sometimes you still make mistakes. Well, we made one here. Fortunately, we did not expend too much time chasing a cave that didn’t exist.

Once this was unfortunately determined, the mapping team continued their work on Traga Luz Grande. Progress with the volumetric mapping is moving forward on this feature and it should be complete within the next three to four field days.

After this was done, the sensor deployment team have some redemption. Firstly, we named Cueva Sin Nombre. It is now Cueva Cebeza Encogido (Cave of the Shrunken Head). When we were up climbing around the first entrance the mapping team found to this cave, Pete observed a really cool salt formation that looked like a throne with a man with a shrunken head sitting upon it. And, so the cave was named.

Pete is belaying Lynn using a sitting stance to get down a 20 foot steep-sided cliff.

This afternoon, Pete, Lynn and I up found a route up and around this lower entrance of this cave. As I’ve mentioned in previous blogs, all the caves in the Atacama are piping caves. So, we went up slope to find the other entrance to Cueva Cebeza Encogido. We were unable to move through this cave due to a 20 foot vertical dry fall which prevented us from pushing this cave from the lower entrance. As we were walking along the lower flanks of the Cordillera de los Andes, we found an upper entrance which we thought may be the other entrance to this cave. So, we went in. This is a really nice cave. As with all piping caves, this cave snakes around quite a bit, so we pushed this cave through.

Lynn within Cueva Cebeza Encogido. Credit: Pete Polsgrove.

What I really liked about this cave is that it became really warm. As I have learned from studying cave thermal behavior, some cave deep zones reflect around the average annual temperature of the surface at some point of time in the past. Because the Atacama can be quite hot during the summer, I would suggest, that if this is correct, cave deep zones in the Atacama should seem much warmer during the austral winter. This cave was warm. Also, from what we can discern thus far, this cave probably has only three entrances and one skylight – this “simple” structure has been quite rare in the Atacama caves.

Placing a sensor on the surface outside Cueva Cebeza Encogido. Credit: Pete Polsgrove.

Well, we were successful! When we got about 200 m back in this cave, the passage bifurcates. From what we could discern from within the cave, we thought the left passage would ultimately connect with the lower entrance. I went back about 10 m and the passage became really tight. I backed up through this passage and we discussed that one person would go back down, enter the lower entrance, and then yell into the cave from the other side to see if we could hear the other person. If so, then we would know the passage connects. However, we still had the right fork. So, I decided to push this passage to see if I could reach the surface.

Lynn decided to wait at the bifurcation point, while Pete and I went on to see where this passage went. I took the lead, and after about 75m I started to feel cool air. I knew I was near the other entrance. I continued pushing this passage and I then found a sky light.

A couple of days prior when Pete and I were at the lower entrance to Cebeza Encondido, we turned off our lights and we saw a faint light on the upper ledge beyond the dry fall. We thought there was probably a skylight up there.

I started to get stoked at this point. I felt that we had found the connecting passage to the lower entrance. I was right! I went a few meters more and there was our dry fall. Golly, this felt really good! After the snafu with Roberto/ Chulacao cave, we had a good sense of accomplishment and redemption.

With this confirmed, we deployed sensors in the upper passage and within the cave deep zone. We then returned to the surface, and Pete proceeded up canyon to see if there was another cave within this wash. He found one and we will check this out tomorrow.

We still have the lower left passage of Cebeza Encogido to suss out. Personally, I think this passage will be too tight to push. However, Knutt feels optimistic that the mapping team can push it. We shall see. If they are successful, we will emplace another sensor at the other entrance (we know this piping feature spills out into the canyon below at some point). If not, this side passage will be labeled as too tight and we will not be able to map this segment of the cave.

Christina and John on the return from Traga Luz Grande. Credit: Dan Ruby.

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