Day 8 - Pancakes for Breakfast!

The sun arose, we packed our things, and hit the road, ready for our second roadside outcrop adventure. Sitting aside the road, with cars speeding past (or inching forward, I'm looking at you, log trucks), we discussed the truth behind the outcrop in front of us. After establishing our location, which was a few kilometers northwest of Jaquirana, we started sketching, and resketching and RESKETCHING the outcrop before us. Getting just a little hammer crazy, we began discussing our observations. It appeared that the outcrop could be generalized into three different sections, separated diagonally, like a rhombus. The rocks above and to the left were different from those below and to the right—the latter rocks appeared to have a striped or laminated pattern. Finally, we had reached a point of conversation: breakfast.

That's right, the rocks had pancakes in them! Don’t get too excited though, these stripes, which thinned significantly as you moved down the outcrop, were simply deposits of explosive volcanic material that deposited progressively to create a thicker deposit. As more pancakes deposited, pressure increased, flattening the older deposits and creating these different effects. Confused? So were we, but it’s simple! The deposit just squished itself! A unique phenomena yet to be formally labeled, we referred to the pancakes as “Barbosas”. This outcrop was our first example of not only an explosive eruption, and one currently believed to be the result of continued and sustained explosive eruptions piling on top of one another.

The fun didn’t stop there—one outcrop down, two to go! After noticing an interesting curvature in the flow banding of certain rocks (shout out to XJ for his brilliant work), Guil and Lydia (miming and sound effects included) guided us about 200 meters up the road to a second outcrop, one that would be the most curious yet. Immediately we noticed that almost all of these stripes and pancake formations were curved, twisted, and scrunched up! How you ask? Let me explain. As the flow continued, the magma melt began to collapse under its own weight (don’t we all?) causing the twists and turns in the flow banding we were observing. These were some of the most mysterious and interesting rock formations we had yet to observe, but we weren’t done yet.

Our stomachs full with, yep, you guessed it, more bread and cheese (and strawberry wafers), we headed back to the cars with one more outcrop to go. After slight distractions from the farm animals (there were piglets, y’all!) we actually hit the road. 20 kilometers east of Bom Jesus, our final outcrop contained larger Barbosas with fewer twists and turns. An always-excited Guil eagerly informed us that the presence of larger blobs (recap: these are the result of juvenile blobs of explosive magma,) indicates that this outcrop was probably closer to the source than the first two, OR it was from a bigger eruption. 

Essentially our day had involved us progressively moving chronologically backwards, constructing a timeline of this massive 135 million year old deposit. Somebody call Dr. Who—we had effectively traveled through time!

Until next time,

Volcanic Virginia and Silicic

Scott

P.S. We stayed at a gas station last night, so that was fun, too…

Day 7 - Don't Go Chasing Waterfalls

We woke to encounter what Guil called the “Brazilian way”, some fried cheese empanadas made especially for the few vegetarians in the group. With the moans and groans of aching calves we set out on our next adventure.  After loading up the cars and driving once more over Ali’s dreaded bridge, we crossed into Santa Catarina state and arrived at our next destination; an outcrop split by a cascading waterfall. At this outcrop, Guil gave us our first true graded test as budding geologists by separating us into pairs to make observations and form hypotheses on the origin of the rock formations shouldering the falls. As we developed our theories, Guil and Lydia, accompanied by a dexterous goat, journeyed down the rock face to collect samples for their ongoing research at the site. Although most of our explorations thus far have concluded with an explanation of the local geology, this was our first encounter with an outcrop for which our instructors didn’t provide a definite answer; we had both literally and metaphorically arrived at the cutting edge of geology.

After a couple hours of making observations, we all packed into the cars to eat lunch, away from the wind that nearly blew some of our tiniest members and a few cucumbers away. Unfortunately, disaster struck once again. Guil hauled our TA’s out of the trunk of our favorite car, Eugene, who was revealed to be suffering from a flat tire. Fortunately, Eugene was hiding a spare and our handy instructors were able to fix him up and send us onward to our next outcrop. At the next destination we were given the much-needed opportunity to relieve the stress of our previous test and smash some rocks. Although the rocks put up a worthy fight drawing first blood in the form of Matan’s finger, Virginia and Andrew emerged victorious with samples. Some were almost the size of the tiniest members of our group. After this thorough pummeling, we investigated the remains and learned that there were two different kinds of rocks: a glassy silicic rock studded with amygdules, and a courser grained rock that turned out to be a surprisingly young basalt. Based on these compositions and our observations of the sharp contacts between the rocks, we came to the conclusion that the basalt intrusion was a dike, and proceeded to confirm its orientation with our compasses. Following some minor confusion, we measured the orientation to be at 5-10 degrees N. This seemingly small observation contributed a powerful piece of evidence towards the geological phenomena we observed yesterday. The north-south orientation of the dike probably filled in the thinned crust, which formed during the east-west split of South America and Africa 135 Ma. Finally, we had some solid support to back up Guil’s wild theories.

Once we made our way back to the cabins, we had the option to go on a short hike to a waterfall nearby. Some of our more weary members decided to take a much-needed nap, while the rest of us packed up in two cars with Lydia and Guil and left for the next adventure. After scaling up another very steep hill which reminded us all too much of the previous day’s treacherous climb, we were treated with quite a sight. On our way, when Ryan asked Lydia to rate the magnificence of the waterfalls on a scale of zero to Niagara Falls, she responded with a three; when we made it to the overlook, we realized that she had vastly undersold what turned out to be the most beautiful falls we have seen in Brazil so far. Of course, Nick couldn’t resist hop-scotching across the questionable rocks in the waterfall to get close to the edge. Not to be left behind, all the others followed suit, which led to an interesting exercise in team building when we got stuck on our way back to dry ground. Guil may have gained a few grey strands of hair during this, for which we take no responsibility.

At the end of the day, we all gathered in the restaurante to have our fabulous final feast at the Monte Negro cabins. Another fine example of Brazilian hospitality was the meatless lasagna for the hungry vegetarians, which made Jen explode with joy. The night ended with people packing their bags to leave for Ausentes (via Bom Jesus) the next day. Although we will sorely miss Monte Negro, and all the beautiful landscapes, heated blankets, and world-class meals it has to offer, we can’t wait to see what Brazil has in store for us next.

AvarnYAS and NicholYAS

Day 6 - The Hike to Africa

Today was the earliest day by far, since we were up by 6, if you round down. We had another great breakfast of sausage, cheese, and pastries, just like the other 5 breakfasts we had in Brazil. The Papagaios farm harbored good number of cows, fierce bulls, horses and most importantly, like 20 puppies. However, little did we know, this would be the hike of our geological lives.

It all started out easy enough, walking on a dirt trail with only the occasional rock to avoid. After a solid kilometer of reasonable hiking, we reached the end of the trail. Then we had to create our very own path as we hiked along, confused about what or where our destination was. Our confusion was especially exacerbated by Guil’s abrupt 90 degree turns. We reached a wet marshy area where the cows and horses grazed. Suddenly we had to leap across treacherous streams on little stones and quick-step through deceitful grasses. REI apparently told Avarna that her boots could handle the game, but empirical evidence in the field suggests that she was wet up to the knees. Meanwhile, we also had to worry about weaving around the plentiful cow dung.

No one knew what to expect from today, but when we reached the escarpment, we saw the most breathtaking view as of yet, and our hike definitely paid off. The favorable conditions allowed our sight to capture the civilization past the valley below to the ocean beyond. And with a little Earth science to enhance our sight, we saw Africa. In the Cretaceous period, the Equatorial Atlantic Gateway opened up and the sedimentary basin that once connected South America and Africa separated. Standing on the western graben in Brazil, we gave a shout out the now distant twin brother in Africa, the eastern graben of the volcanic rocks. 

After taking in the sights, we headed back the way we came, facing the same hazards along the way. However, we made some stops at important geological structures, including obsidian rocks (volcanic glass) and areas with rocks that had geodes. The principle of bubblization was also introduced. The vesicles we saw indicate that the magma flowed effusively. In other cases, when there are sufficient volatile gases in the magma, the magma most likely travels with a loud KABOOM, as Lydia would illustrate with her large collection of sound effects.

When we finally returned to the Papagaios farm, Pablo, waking up from a Gucci nap, and lots of food greeted us. At dinner, the usual good ol’ downtime kicked in. Virginia had the cocktail of the century and the rest of us relied on beer and Catafesta.

Rhyolite Ryan & Xis Jota (XJ)

Day 5 - The Grander Canyon

We’ve been here 5 days now, and everyone who was overly excited to make rock puns already volunteered for blog entries, so adjust your expectations accordingly.  We started off the frigid Monte Negro morning with breakfast and proceeded to pack the cars. Then we embarked on the journey of a lifetime, complete with sketchy dirt roads, confused cows in the way, and great driving tunes.

We started off our day’s excursion by hiking about 15 minutes to our first outcrop where we were able to view a huge cliff off in the distance on one side and a waterfall on the other.  We could tell by the vertical jointing displayed by the outcrop that it was similar to the basalt one we studied yesterday allowing us to identify it as an igneous rock formation. After our distant observations of the outcrop, we marched over the river and through the woods — and over some tetanus-infused barbed wire — to more closely observe the outcrop. Up close, Guil and Lydia elaborated that there are often things that we cannot determine simply by observing a rock, but rather we need to take samples back to the lab and observe them under a microscope. While our intuitions led us to believe that the rock was a basaltic lava flow, we learned that this outcrop was actually rhyolite — a silicic igneous rock with a high viscosity.

During our conversation about the rocks, clouds approached us through the canyon and slowly engulfed us, cutting our visibility but making for some pretty cool silhouette pictures.  Our lunch today was packed by the Pousada Fazenda Monte Negro, the Brazilian Dude Ranch we’re staying on, and the sausage and cheese sandwiches almost made for a nice change from the ham and cheese sandwiches we’ve had the past five days.

Today also marked our first mini-lesson in ecology, with yogi Jen taking the lead in explaining how the deforestation around the canyon is due to cattle-ranching. Today marks a monumental moment in our Maymester, as we were finally able to sketch something other than rocks — plants. Following these sketches, the groups split in two with one group proceeding to another outcrop and waterfall, while the other group proceeded back to the cars to regroup, and of course picked up another stray dog along the day.

Finally, the separate camps reunited to observe our ultimate outcrop. Here, we found yet another igneous rock formation, similar to the initial cliff we studied but weren’t fortunate enough to rappel down.  However, by observing the similarities in the features between the two outcrops we were able to interpolate that, upon closer observation, the vertical jointing was in fact columnar jointing caused by the pathways of heat loss in the magma.

To wrap up our eventful day we moseyed our way back to our cabins for some ice cold showers and pre-dinner naps in preparation for a much-needed Brazilian feast.

Sugar, Spice, and Everything Nice,

Grant 1 and Grant 2

Day 4 - Friday the 13th

Waking up in Farol for yet another breakfast of bread, cheese, and cold cuts, the group was off to a rocky start. Five of us woke up sick and Andrew's toe didn't look like it was getting better. The omens of Friday the 13th were upon us.

As we were preparing to leave, we saw the town come together to bring in the day's catch of fish. With tears in our eyes, we said our good-byes to Trooper and as we made our way up the path, Friday the 13th struck again; this time, in the form of a flat tire. Luckily for us, a gas station was just up the road and we managed to fix our tire, but only after an hour.

Our day's adventure was just beginning. Our first stop was at a quarry near Lauro Muller where yesterday's rivalry was rekindled. Today's argument was about the origins of the laminated black rock. The quarry itself was full of this laminated black rock with periodic strips of banded white rock. We quickly came to the conclusion that the white rock was sedimentary and learned that it was actually limestone, but the origins of the black rock still evaded us. The girls thought that it was volcanic rock and the guys thought it was sedimentary rock.  But in a historic change of events, one that will be written in the history books as the turning point in this great feud, the guys came out on top. The black rock was actually shale--a sedimentary rock that was formed in the deep marine section of the ocean.  As the debate wrapped up, Andrew showed up with some great news--his toe was not actually broken--just fractured in a bunch of places. Suddenly, it seemed like our Friday the 13th was turning around.

Next on our journey, we continued to ascend the escarpmemt, stopping 3 more times to observe changes in the preservation of sediments. We saw how deep marine transitioned to shallow marine and how shallow marine changed to sand dune sediment, skipping over coastal altogether! We deduced that we were looking at preserved sand dune sediment because we observed that its spherical grains resembled the grains at the dunes the day before. It turns out the that coastal sediment was not preserved due to erosion. At our last stop, we saw the transition from the sand dune sediment to a massive fine grained volcanic rock that we determined was basalt. Shockingly enough, we found that this volcanic rock continued up for 300 vertical meters--much further than Pablo (Emmanuel) ran today, but shhh, don't tell the athletic department.

From there, we took a very long and bumpy road for what seemed like hours, but eventually we reached Montenegro where had electric blankets and a hot meal waiting for us.

All in all, it seemed like our Friday the 13th turned out pretty well.


Rock on,
Metamorphic Matan and Sedimentary Sam

Day 3 - Brazetas

Guil began the day by saying "The present is the key to the past." With this in mind, we returned to the Farol de Santa Marta mountainside to synthesize some of the concepts we had learned over the past two days to understand the new topic of sedimentation.

Our steep trek up the mountainside included a surprise: a friendly, 3-legged stray pooch from town followed us into the field. The 3-legged hound (or Trooper, as we affectionately called him) seemed to be out hiking all of us. Especially showing off to our 1-legged friend, Andrew (who had injured his toe in a football match with some locals the night before).

Our first stop of the hike took us to the high altitude Sambaqui lookout where Guil gave us the basics. Sedimentation is a lot like a bad relationship: complicated and lasts for way longer than it should. It's a process that involves almost every part of the landscape and relies on complex interactions between energy, distance, and density. 

After bioturbating all over the place and coming to a conclusion on the regulation grain size of sand (.6 - 2mm), the group ascended one of the large dunes. Little did we know that climbing this dune would result in one of the greatest geological showdowns this Maymester has ever seen. 

"How did these dunes form?" Guil asked innocently. The dune, shaped like the top half of a capital letter "D", proved to be more complicated that originally predicted. After investigating the morphology of the dune and the direction of the wind, two strong opinions formed. Virginia and Carsen contended that the wind was depositing the sand on the curved side of the "D" while Nick, Emmanuel and Sam contended it was being deposited on the straight side. 

And thus began The Great Dune Debate of 2016. On which side was the sediment being deposited? Were the deposits vertical, giving rise to the sheer, cliff-like side? Or were the grains being deposited along the horizontal, gradually sloped side? After a bloody battle of words and a cracker-filled lunch, Guil revealed that in fact the women were correct.

Funny how two of those in the winning camp authored this blog post. But we suppose it's the victors who get to write the history books.

Just as the present is key to the past, we ended our day in the field by returning to the Sambaqui lookout and proceeded to absorb the entire landscape: the ocean, dunes, interdunes, vegetation, our beloved first outcrop and everything in between. It was a nice way to end the day, synthesize the geological concepts, and say goodbye to the landscape.

As our time comes to an end in Farol de Santa Marta, we are looking forward to the countless adventures and fish dinners that lie ahead.

ZLAM, 

Ali and Carsen

Day 2 - Pablo the Explorer

Emmanuel and Benny D

After trekking for 20 minutes across the jagged landscape, as we walked over the final stretch of greenery, the landscape suddenly transitioned into dunes and deserts. From our higher vantage point, we looked out and we saw a scene like in Mad Max (or like the beginning of Star Wars) with sand dunes stretching out over the horizon. The contrast was so dramatic, the ocean and the ponds looked like mere mirages in the distance.

A gust of sand hit our faces when we started entering the desert to reach the outcrop we saw yesterday: an outcrop that we examined from afar the day before. Using the yo-yo method, we looked at the bigger picture and saw a weird brown staircase. Today, we were going to zoom in.

We all gathered around the funny staircase and learned about dikes, faults, joints, and contact metamorphism. We used our newly gained knowledge to identify the dikes that we saw on our way back and how they formed. Which came first? The rock or the dike?

Most of the time, we concluded that the dike formed after the pink rock (granite) that surrounded it.  We arrived at this conclusion because the rock that the dike was made of had color differences in the contact zone with the granite (we knew this was a granite because of our mineral classification class earlier in the morning) while the granite was uniform throughout.  This observation was highly supportive of our hypothesis, as the “stairway” was intruding on the preexisting granite foundations. We traveled back in time to understand the history behind the rocks.

We then took our conclusions and deduced that the magma content that these two distinct rocks came from were different – cooling at different rates. We also learned about inclusions where one magma composition would wrap around another.

Then we picked up on our journey and traveled on the coastline and began to identify the different kinds of faults and examined how they formed. We could see with our eyes the horizontal movement that the rocks displayed. As we wrapped up, we continued our journey across the coastline climbing rocks up and down. We saw our friends almost fall down deep holes that were as deep as some of us are high. I mean, we did learn about the dangers of joints.

After we got back, we jumped into the water and took some waves and played soccer with the locals in a pickup game. While we were fine with the temperature, they thought we were crazy to run in such  “cold” weather. Though we thought we were pretty sane. Lets see how much longer that lasts…

Stay tuned for day three and what tomorrow may hold. That is all folks!