Volcano Fieldwork Part 2

February 17-20th: What is this rocky prairie? This photo was taken just seconds before the clouds moved in completely to take away the view of the summit dome. My volcanological companions and I visited Volcan Baru´s amphitheater during an uncharacteristically rainy week. After exploring the area of La Yeguada with PCVs Karinne and Noah, we took the Interamericana, headed west, then drove due north to the volcano. This was a good time to visit the largest known debris avalanche in Central America. The photo above is a view into the amphitheater of Volcan Baru. We are standing on a lahar surface and looking roughly East up into the dome complex. Too bad about the weather, the summit antennas are already hidden by the incoming rain.

Since we had the benefit of several great geological minds, we took time to look at a phenomenon very different than lava flows. Debris avalanches are dramatic, but very rare events at volcanoes. By rare, I mean that they don´t happen every day but many volcanoes around the world have collapse features like what you can see at Baru. Some preliminary studies describe this particular deposit as the largest in Central America. What does that mean? At this point it just means that a whole lot of mountain fell down many thousands of years ago.

Want to know more about hummocks? Go here: USGS VHP

Events like this are very interesting for a number of reasons but I´m interested in them because they scoop out a volcano and create new terrain. After walking around Mount St. Helens for a while in 2004, I developed a particular interest in the features called hummocks. They represent coherent blocks that tumbled, slid, or floated along with the rest of the debris that made up the flanks of a volcano. Here´s one outcrop of a hummock but it represents a blocky phase and lacks the multicolored characteristic typical of most hummocks:

(Bill, Guillermo, and Karinne for scale)

In the fan of deposits from Baru, you can find these hummocks and start to get an idea of how the collapse took place- this could be good thesis material.

Thanks for taking the time to visit and brainstorm project plans, everybody - this was a valuable series of fieldtrips!

Volcano Fieldwork Part 1

February 13-16th:
First few visits were to the Cerro Colorado region (Comarca highlands) and later Volcan Baru (to Boquete unfortunately during the same time as the jazz festival; no time to listen to music!).

We weren´t sure exactly which peak was Cerro Colorado, but we sure found the copper mine area easily. The view here is roughly south looking out from the terraced area where mining might continue in the future. We found some interesting deposits that we didn´t quite expect here; there were layers of pumice that must have come down from a volcano located higher up in the mountains. Where? Not sure yet, but for us, the pumice is far more interesting than measely copper veins!

After the quick visits in Chiriqui, we visited La Yeguada volcano in Veraguas. Before reaching the dome complexes, we stopped at a river crossing.

Here I am pointing at a kettle-like feature in the surface of a highly-jointed (entablatured jointing) ignimbrite.

We debated if this was a very glassy andesitic lava flow, but there are flow bands and compacted pumices (fiamme) within the unit. This is an interesting outcrop to study but also intreguing for the artistic eye.

The visit to La Yeguada provided a glimpse of what Karinne had been working with - heaping dacitic domes in an ill-defined crater with a poorly constrained age. This is a difficult field area...

Panama City

February 1st and 2nd

It´s Carnival time in Panama and I had the luck of travelling to Panama City just as it started. That luck ended up kind of badly, I really wasn´t there to celebrate and dance in the streets, I just had to visit the dentist and wasn´t really prepared to explore the festivities solo. Do I have photos of the parades or costumes or crazy vendors? No, but I can share 2 photos that compare interesting views of the city: The Old and The New.

Sorry the experience wasn´t more interesting. Likely this post would be more meaningful if I also put in a note that ¨Yes¨ the SuperBowl was the following Sunday but ¨No¨the Patriots did not win. Okay, next year I won´t be chicken and I´ll check out a Carnival... Extra note, travelling by bus anywhere in Panama will be dicey during this week of fiestas- especially in and out of Panama City and Santiago. Expect super long lines in the bus terminals; the line was so long that I considered the $80 cost to simply fly back to David from Panama; it would have been a 3 hour wait in line, plus the 8 hour trip by bus, plus the inconvenience of arriving at a ridiculous hour in the morning - hmmm, that could be worth $80...

Fieldwork In Burica

For a little more than a week, I joined a PSU grad student working on the geology of the Burica Peninsula.

We began in Puerto Armuelles, the most populated town in the region. The goal was to map the peninsula to determine what structural features are present that indicate faulting. Already aware of the Triple-Point Junction just offshore from the point of Burica, we were prepared to encounter fault characteristics throughought the entire region. An interesting feature that I wasn´t familiar with is the series of benches that form when shorelines are repeatedly uplifted. We could drive by such structures and note: Yes, there´s another one!

Previous work has been conducted in this area - a region shared almost equally with Panama and Costa Rica. As we used the former published work for a reference, we learned what details needed to be added to the first map and also how the structural model will have to be changed now that new evidence exists for different geologic mechanisms.

This work will continue over the next few years - there´s a lot of terrain to cover on foot! Few direct routes exist for crossing the peninsula and a number of traverses will be necessary to trace such large-scale features as synclines, normal faults (or was it transform?), benches, and truncated lahar flows.

I hope I can join the field mapping in the future!