On day 8, our team was joined by Scott Brame, a professor at Clemson University. With his guidance, we set out to investigate some of the unique volcanic geology of Dominica!
We made our way north along the coast and stopped near Coulibistrie to document evidence of island uplift. Dominica is growing as new volcanic material is added, and marine life preserved above sea level is great evidence of this. The outcrop contains staghorn coral that grew in the ocean and boulders that came from the land. These were mixed together in a shallow offshore setting and subsequently uplifted.
A lookout to the Caribbean through section of uplifted coral.
After Coulibistrie we made another stop along the road and checked out a very colorful wall. This is the Du Blanc outcrop showing a block and ash flow deposit that has been hydrothermally altered.The red and yellow colorations denote different levels of oxidation and reduction of the minerals that were in the hydrothermal fluids.
An outcrop of hydrothermally altered block and ash flow.
After going up and down more winding roads, we found a place to stop and get pictures and video of this beautiful feature. These surge deposits on the road just south of Toucari Bay represent gas and rock fragments ejected during a volcanic eruption with a much higher rate of gas to rock particles. The surge deposits display wavy bedding and are overall well sorted with rounded pumice lapilli. The deposit is underlain and overlain by block and ash flow deposits which indicate it might be associated with a volcanic dome collapse.
Roadcut view of surge deposits south of Toucari.
We ended the day by hiking to one of Dominica’s coolest (in both senses of the word) spots: Cold Soufriere. The springs at Cold Soufriere offgas a significant amount of carbon dioxide and sulfur dioxide, the latter accounting for the pervasive smell of rotten eggs one encounters at the site. The origin of these springs has two possibilities: one, that the hydrologic system is no longer in contact with a magma source or two, that the magma has cooled sufficiently but still contains abundant dissolved gases.
Today was a long day, but it was absolutely worth it to see all these stunning features!
- Stephanie, Emily & Katrina
Clemson Geopaths interns
On day 7 we headed to Scott’s head, which is a tombolo. A tombolo is when the mainland is attached to an island by a narrow piece of land such as a bar or a spit. This one in particular is even more special because it has the Caribbean sea on one side and the Atlantic on the other.
On the left is the Caribbean sea and on the right is the Atlantic Ocean.
Today we were focused on the Caribbean side and took more sand samples in several transects as well as water quality samples, just as we had taken at champagne reef.
The reef can be seen well from above. We estimated that only about 15% of the coral is still alive in this cove. The reef had been damaged severely, most likely from a combination of increased acidity, storm damage, and rising temperatures. This means we did not see as many fish, crabs, or birds as we expected. Without this important chain the local people have to fish out farther and tourists don’t have such an incentive to come here, thus hurting two of Dominica’s largest drivers of their economy.
We hiked to the top of the peninsula and got an amazing view of the area. Check our facebook page to get a look at the 360 image (Clemson Geopaths). From
You can see the tops of several forming sea stacks.
These features form over large swaths of time as waves slowly erode a sea cave and collapses the ceiling. This leaves a stand alone stack in the water.
Overall it was a gorgeous and productive day!
-Emily, Stephanie, and Katrina
Day 6 was mostly spent in the water. We headed back to champagne reef to take several transects of sand samples and water samples. A transect just means we took a bunch of samples in a line, writing down the lat. And long. Of each sample. Emily, Stephanie, and Sawyer were in the water and Katrina and Dr. Lazar stayed on the beach to do tests and get some video for the geology outreach project.
Katrina works on taking water quality measurements on the beach.
How we kept our camera equipment dry when a sudden rainstorm appeared. (shout out to Clemson RiSE – Residents in Science and Engineering - for the awesome hat!)
Once we were back at the research center there was still plenty of cores left to be opened up so Stephanie and Dr. Lazar continued their work with those late into the night! Katrina and Emily played catch up on photo documentation and projects.
-Emily,Stephanie, and Katrina
Day 5 started out at Archbold Research Center and we all split up into teams to tackle some projects for the morning. Stephanie and Dr. Lazar began opening some of the cores that we have collected over the last few days.
Dr. Lazar (right) and Stephanie (left) examine a core they have just opened.
This process is extremely time consuming and meticulous. Each core is cut in half and then each layer (sand, marsh, peat, or whatever else may be found) is documented in a core log chart and photographed. The first characteristic described is the color, using a Munsell chart. This chart allows them to designate the chroma and value of the colors. Other important details to note include any changes in sediment type, the amount of shells and organic material, and grain size. This information will then be used to create a core log that will show the layers present at the site. The hope of the research is to find any evidence of hurricane deposits. Stephanie received a Southeastern GSA undergraduate research grant, and this money will be used for carbon dating part of the core. This date could then help to pinpoint the hurricane frequency of the past that we could then compare to the present.
Sawyer and Emily set out with a handheld GPS to improve one of the existing maps of the research center. In the end some slight modifications were made to one of the trails and a stream.
Some photos from around the center. A gigantic mossy tree, those roots are about 3 feet tall! A blue snail (Drymaeus laticinctus) a relatively rare tropical air-breathing land snail endemic (native) to Dominica.
Dr. Moysey and Sawyer also installed a water level logger on the property to measure stream flow and storm events. We are hoping this can grow into a citizen science project for the research center.
Since it was Dr. Moysey’s last day we went into town for dinner. Half of our group was brave enough to try the local lionfish. The lionfish has venomous spines so it is not a traditional delicacy. However, it is an invasive species, meaning that it comes into a habitat and multiplies quickly, pushing other organisms out and harming the ecosystem. It’s become such a problem around the world that chefs have come up with creative ways to prepare them so they are edible in order to keep the population under control.
Have a great evening from our crazy awesome team!
From left to right: Katrina, Dr.Moysey, Emily, Dr.Lazar.
Today’s adventures included more beach visits for water and sand samples. Our longest stop was at Woodford Hill Beach, where we began water chemistry analysis. We looked for dissolved carbon dioxide, pH, alkalinity and salinity.
Katrina uses titration to determine the dissolved carbon dioxide content.
We found some promising layers after digging with a shovel, so we took several cores. The first was to take a core of the surface level down 60 centimeters. The next started 60 centimeters down to 120, and lastly a third core to get samples down to almost 180 centimeters. We had to dig a second hole to stand in to reach far enough down to get the first hole to the 110 centimeter requirement.
Later that day we visited Thibaud Beach. It was split into two sides: one was rocky, one was black sand. The side with black sand had a rock formation that stood out to us because of the vibrant colors.
Emily climbed on top of the rocks to get some up-close pictures.
Once the cores were safely back at the research center, Stephanie began to process them.
Stephanie starts opening a core. The first step is to cut the tube to the recovery sample. This means cutting open the top. Then, to look at the core, you cut two long slits into the sides of the core to expose the material inside. To start logging, she scrapes off the outside to get a look at the untouched inner part of the core. The details are then logged and photographed.
- Stephanie, Emily & Katrina
Clemson Geopaths interns
The goal today was to get as many cores as possible for Stephanie’s project. To achieve that, we went to several different beaches and looked for areas that looked likely to have been affected by storm surges. These areas needed to be close enough to the water to have the storm deposits and far enough to have marsh deposits for dating. First stop: Rosalie Beach! This seemed like a good location because of the nearby marshy areas.
To get to this beach, we ‘had’ to stop at this beautiful little resort (to get permission).
Behind the resort, there were stormy black sand beaches.
The black sand is made from crushed up volcanic rock. These rocks are high in dark minerals that give the sand its black appearance.
We made sure, with the help of a guide, that we would not disturb the turtles that lay their eggs at this beach. We also found some places that we thought may have had a history of storm surges.
Stephanie digs a hole to examine the layers while Dr. Lazar provides guidance.
After Rosalie, we headed to a nearby rocky beach to look for similar spots.
There were definitely some interesting features at this beach, and it was clear that the storms here can bring in intense and unpredictable waves as well as high winds as can be seen in the trees on the side of this cliff.
We took samples at Delices Beach behind large rocks that would potentially slow the receding water and lower the water energy for foraminifera to be deposited in the area. We then can use the core to see the record of storm events by identifying the ocean foraminifera that were taken up onto land and deposited there.
Overall, we managed to recover seven cores that look promising. A very successful day!
We started off the day getting our drone up and running. We’ll be using this throughout the next week and a half to document some features that are more difficult to see on foot.
This photo is of where we are staying, with the drone about 70 feet up!
Though some of our work is fun and involves drones, some is less glamorous, like getting permits to do research, especially in protected areas. While most of the paperwork can be done in advance, there is still the matter of going to town and collecting and signing all the documents… fortunately for us, ‘going to do paperwork’ in Roseau puts us right next to Champagne Beach! Naturally we decided to investigate.
Some of our favorite shots from Champagne Beach.
One of the main draws to Dominica is the underwater bubble streams that give Champagne Reef its name. For us, they are of particular interest because of the research Dr. Lazar is working on. We had to wait until 5 for the permit to research in the reef, so we used several hours to snorkel and select spots that looked most promising for samples.
We entered the water and almost immediately were greeted by 3 squid. We also noticed small CO2 seeps in the shallows here.
We headed out deeper and the larger CO2 vents proved easy to find. They ranged in size and bubble frequency and were spread all over the left corner of the beach. Many of the rocks featured fractures, which were abundant with the seeps.
Of course, the CO2 seeps were not the only highlight of the snorkel. We got to play with anemones, by brushing seaweed lightly by it and watching as the anemone grabbed onto it. We then were able to catch a glimpse of an octopus as it hid away in a crevice of rock.
The actual ‘beach’ on Champagne is mostly rocks but there are a few spots with black sand. The black sand comes from the volcanic materials like basalt, augite, hornblende, iron oxides, lava fragments, and volcanic glass being broken up rather than the calcium carbonate and quartz that make up white sanded beaches.
Tomorrow, with our permits obtained, we will begin sampling various beaches around Dominica!
The Clemson Geopaths team is in Dominica! Our mission today: to explore and mark out the best places for further study in the next two weeks. The first stop was this incredible cliff face right off the main road, which had clearly defined layers of large rocks and fine sediments of varying colors. The most interesting part about these layers was their direction. Usually sediment layers are found parallel to the ground, but here they are diagonal and even switch direction every few meters!
Dr. Moysey and Dr. Lazar discuss the unique features of these cliffs.
Similar rock features continued to follow the road throughout Dominica, making it clear why so many geologists choose this island for their studies. Yet alongside the beautiful, vibrant features lie stories of a different nature. Tropical storms and hurricanes ravage the infrastructure, ecology and coastline – leaving behind devastation and permanent changes to the shape of the land.
Dr. Moysey explains how the river has changed over time, and how we can predict future changes.
A large section of geology dedicates itself to studying how coastlines are likely to change over time based on past events and predicted future ones. This sustainability focus includes recommendations on where to build new structures, and what may be done to preserve current ones.
The remains of a bridge built in 2015
A bridge immediately next to the previous destroyed bridge, built in 1921 and still functional! (But not built for cars to drive across.)
Clearly, there are some questions to be asked if a bridge built so recently can be destroyed while one almost 100 years older remains.
Emily investigates more evidence of storm damage in Dominica.
The later part of the day was spent in the water. We visited Toucari Beach and were able to snorkel out and find CO2 seeps. These seeps release streams of CO2 bubbles and are evidence of volcanic activity of Dominica.
We ended the day when afternoon thunderstorms chased us out of the water. As we headed back, we stopped for ice cream! We were able to try local flavors like banana, coconut, and passion fruit.
They were delicious! (left to right: Katrina, Emily and Stephanie)
(Sorry for the day-late update. The internet and power was down due to the lightning storms!)
Kwaj has a very close tie to World War II. The Marshalls were under German control until they were handed over to the Japanese. In WWII, US forces fought to take control of Pacific islands, including Kwajalein. The battle to take Kwajalein involved one of the heaviest bombings of the war; over 15,000 tons of ammunition was dropped onto the island. It then took 4 days for the US troops to move in.
The original Kwajalein island is smaller than it is today. During the Japanese and US occupation, they dug and/or bombed holes in the coral reef surrounding the island. They then used this material to extend the length of the island to almost 3 miles long.
At low tide, these tide pools are accessible. The inside of the pools are often home to sharks and other sea creatures that get trapped as the tide rolls out. This give you the chance to take a look at some animals that are otherwise hard to find. Low tide exposes some of the reef and can be explored.
Clemson Geopaths Intern