Day 5: Thursday, 1/11/2018

by Gabby Davis (19′) and Morgan McGlashon (19′)

Today we moved from San Jose to Manuel Antonio, a coastal town by Parque Nacional Manuel Antonio! After an eventful few days in the city and nearby Volcán Turrialba, we are excited to see the ocean. The main events today included looking at uplifted terraces along the coast and parent material (modern beach sediments).

Pete and Kristina describing how the geology has changed from San Jose to the coast along our drive and Matt Barr with the assist for map holding.

We made three stops including one at Playa Esterillos Este where we found recently deposited mafic beach sediments. Next, we gained roughly a meter in elevation and drove about 1 km inland to examine the most recently uplifted terrace (1-2ka).

Eli digging our first soil pit of the trip along a 1-2ka terrace near Playa Esterios Este with Andrew and Pete for adult supervision.

Terraces are formed when sediments are deposited and uplifted during seismic events. Here the sediments were slightly weathered and beginning to form young silicate rich clay soils. Lastly, we stopped slightly further inland and about 40m asl to examine a much older terrace (40-50ka).

Exposed oxisols along the 40-50ka terrace near Playa Esterios Este with Matt for scale.

Here the soil was quite red due to high concentrations of iron oxide and a lack of nutrients as result of leaching. The large time gap between terraces indicates what may have been deposited between 2ka and 40ka was washed away with sea level rise resulting from a warming climate.

Mottled soil in C-horizon of the exposed soil in the 40-50ka terrace.

Liesel and crocodiles

In other news, everyone is thrilled to be at the coast, headed to Parqué Nacional Manuel Antonio tomorrow to look at sediment stratigraphy, and excited about seeing crocodiles this morning along our drive.

Day 4: Wednesday, 1/10/2018

Thanks to one our Costa Rican colleagues, geologist Carlos José Ramírez Umaña of Volcanoes sin Fronteras , Middlebury Geology students were allowed rare access to a hydroelectric dam and power plant currently under construction. The students were lead through the facility by Carlos and Fabián Valverde, one of the head geologists on the construction project, and learned about the importance of geology for such major construction projects. Fabián explained how it is critical to consider many facets of geology for his job, such as bedrock geology (locally, the stratigraphy includes ignimbrites, volcanic breccia, and andesite lavas), structural geology, geomorphology, and engineering geology.

In the afternoon, students spent more time underground touring a different kind of man-made tunnel – an in-progress hotel and event facility dug into a massive ignimbrite! This opportunity allowed students to get a rare glimpse of the interior of pyroclastic flow.

Students view the in-progress dam structure as Geologist Fabian Valverde lectures about his role in the project.

Walking through a tunnel which will eventually bring water to the turbines of the hydroelectric power plant.

Inside an ignimbrite – students pose in the ‘chapel’ of the in-progress hotel and event space built into a massive pyroclastic flow deposit.

Students peer through one of the ventilation shafts in the ignimbrite.

Day 3: Tuesday, 1/9/2018

by Tina Chen (18′) and Sam Cartwright (18′)

Today we ascended the flanks of Volcán Turrialba in our hearty van (named Weefee). Upon our arrival, we were welcomed by falling ash from an eruption that occurred earlier in the morning. Donning our hard hats, we armed ourselves with rock picks before carrying on. Heading north, we passed through a town that was abandoned in the mid-2000s due to the hazards posed by the increasingly active volcano and stopped for a quick lunch. Eventually, rolling green hills of cow pastures gave way to a stark, barren landscape inhabited only by trees killed by the outgassing of CO₂. It was there that we discovered an enigmatic mud channel deposit filled with uniform, sand-sized ash that left us both puzzled and entranced. After a wonderful first day in the field, we made our way back to San José.

Many thanks to Carlos José Ramírez Umaña of  Volcanoes sin Fronteras for making this day possible!

With our trusty Scooby Doo van, Weefee and our amazing driver, Elliott (PC Andrew Hollyday).

A warm welcome into Turrialba Volcano National Park (Accompanied by local geologist Carlos Ramirez).

Turrialba Volcano

Having lunch by the abandoned town of Finca Retiro.

Panoramic view of Finca Retiro (PC Bryce Belanger).

Professor Kristina Walowski next to the ash flow deposit.

GEOL 1035 and Carlos Ramirez (to the right) posing in No Man’s Land!

On the drive home, the group stopped to sample the local cheese varieties, including “queso Turrialba”

Day 2: Monday 1/8/2018

On our first full day in Costa Rica, GEOL 1035 took public transportation into the San José city center to visit the Pre-Columbian Gold Museum. At the museum, students observed incredible gold artifacts and learned about how geology has influenced history and culture in Costa Rica.

After the museum visit, students had time to explore the capital, eat local foods, and go grocery shopping!

Walking the streets of San Jose

Gold artifacts, Pre-Columbian Gold Museum, San Jose

Photo-op outside of the Pre-Columbian Gold Museum

Waiting for the bus, groceries in hand, downtown San Jose

1/7/2018

GEOL 1035 has officially begun! Despite the cold NE weather, delayed flights, and various reroutes, all 18 members of the group made it to San Jose, Costa Rica, safe and sound. Tomorrow, Winter Term 2018 begins!

Landing in San Jose, Costa Rica’s capital city, 7:00am

Tina Chen (18′) waits for her classmates to arrive

The group’s first traditional Costa Rican dinner at La Casona de Laly, in San Jose

This Sunday (January 7th, 2018), GEOL 1035 is headed to Costa Rica! Geology Faculty, Peter Ryan and Kristina Walowski, will be leading 16 Middlebury Geology students on a 3-week excursion.

This 2018 Winter Term Course represents the first installment of the newly developed course, GEOL 1035 Field Geology in Active Tectonic Environments. Through alumni donations, the Middlebury Geology Department aims to make this a biennial course that allows students to experience active tectonics through field exploration of different countries and parts of the US!

Stay tuned – over the course of the next few weeks, students and faculty will post regularly to keep you up-to-date on our travels and share the spectacular geology of Costa Rica!

You can also follow us on Instagram @midd_geology or on Facebook @MiddleburyGeology