Welcome!

Welcome to the blog for the Oberlin College Geomorphology Research Group. We are a diverse team of students working with Amanda Henck Schmidt on geomorphology questions. This blog is an archive of our thoughts about our research, field work travel notes, and student research projects. Amanda's home page is here.

Sunday, December 17, 2017

Hi, this is Jackson.

This is my first time working in the Geomorph lab, and I've been looking into some problems on the software side of things.  The first thing I fixed was a problem with the way the software did calculations for lead.  The calculations originally were modified to compensate for a problem that we have since found another solution for, so I had to find and remove that section of the code.  The person who originally wrote the code is no longer part of the lab, but his comments were helpful in learning how the code worked.  There were also a number of samples that threw errors when calculating.  Some of these only had errors in the batch calculations.

There did not seem to be a pattern the errors, which meant that there had to be more than one cause.  I found that some of them had a problem with the names.  The batch search matched names by only looking at the first two parts separated by hyphens and underscores.  This lead to problems in two situations.  When the name had no hyphens or underscores, it would throw an error due to trying to call the second element in an array that had only one.  I inserted a quick if statement to make it work with an array with length one, fixing the problem.

The problem had another side, which is that when the name had only one part, and then a date, the first part of the date would be added as part of the name.  This was, unfortunately, a problem I could not solve, as some of the names were supposed to have numbers as the second part, so simply making it so that it would drop a part if it was just the number would cause those ones to fail instead.  As such, it is just increases the importance of naming the files with the proper system, which always involves at least two parts of the name.

Currently I am working on altering the program so that it can avoid redoing calculations on samples it has already done calculations on, but I am having some trouble with understanding the section of the code I'd need to use to change this, so I will be studying SQL databases some more, and trying to figure out the other causes of errors.  This was my first experience working with code somebody else had written and data, outside of classes, which was a challenge, but gave me a window into a more practical and professional way of coding.

Sunday, November 19, 2017

Monica and Josh dive into Oberlin's Plum Creek!

Hello Geomorph lovers - 

Monica here!

I've had such a blast working with Josh on the Plum Creek Project. While we may not have posted about it a lot, I've been sampling 4 locations twice each month since the 1st of May this past Spring. It's been a total blast, and despite Harbin (our esteemed Gamma counter) being on the fritz, I was able to muster up enough data to present a couple ideas about what could be happening to both scientists in the field and my enthusiastic Oberlin colleagues at GSA this Fall.

For all of y'all, essentially I am focusing on completing both a spatial and temporal analysis of Plum Creek, investigating the geomorphology of the creek over the course of the year for inconsistencies, patterns, etc. I've done quite a bit of work on the basic 4-spots, twice a month analysis, so Josh has taken to helping me with that, but also thinking about analysis side projects to help flesh out/clarify my data. Before we move to check in with him - here's some fin pics he took of my overtopping my boots in the field. We've had a rainy fall, which means that sometimes you have to get that barely above freezing creek water in your boots, but it's all for the sake of research.




Josh here!

My first semester working in the geomorph lab has been a lot of fun. I've been working closely with Monica on her sediment transport work, and learning a lot about both the underlying geology and the practical aspects of working in a lab. As a physics major, I don't get to go out to do thing very often, and its cool to drive around plum creek collecting samples. I also get to fill the sample analyzer with liquid nitrogen, and dry down samples to prepare them for analysis. In addition, I spent some time trying to learn how to successfully analyze XRD data on different clays, and hopefully I can have Marcus or Ely catch me up on what they've been doing. Something I've really enjoyed has been engaging with all of the relevant literature, as a lot more of the content of the papers is relevant when actually doing research, as opposed to being in a classroom. Even with just this narrow slice of one branch of geology, there is so much out there, and so much to be gained using the techniques. Two thing I want to focus on next semester are continuing to read papers and simply absorb more knowledge and finding my own small project to take ownership of. All in all, the work has been engaging and satisfying, and I look forward to continuing with everything.

Josh's finest photograph of our high-tech sieving equipment:

Monday, November 6, 2017

Mid Semester Updates!



Marcus here,

I’ve been working with Ely to investigate Dominica, an Island in the Caribbean. Over the summer I was fortunate enough to take part in the KECK research project (which you can find posts of if you search through the blog a bit) and this semester has been an extension of that. While I was here in July and August I spent a lot of time in the Geochemistry lab preparing the samples we collected for gamma-spectroscopy. It's a process i’ve talked about before, but essentially we want to create two samples from the original, one with just the coatings of the grain and another with everything else. In this lab we are just concerned with the coatings! This semester has been a little less exciting than previous ones in the lab as we’ve had to overcome a lot of technical and mechanical difficulties.

The first hurdle we had to overcome was a malfunction gamma-spectrometer. Over the summer something fell out of alignment and upon returning to Oberlin in July, we found out that we had been running samples through it but not getting any real results. We tried finding make-shift solutions for this problem several times, but ultimately it seems that the only solution was to send it back and have the manufacturer's repair it. In the meantime, Amanda suggested that we find other ways of collecting data. So we went across the street to the physics department and learned how to use the XRD, or at least tried. An XRD, or x-ray diffractometer, works by shooting x-rays at a solid substance and figuring out how much the refract before returning to another meter. This is useful for figuring out the mineralogy of things as each mineral has a unique structure which diffract rays differently. Ely and I spent several days perfecting our technique on around 20 samples, but hit a small roadblock in understanding what the values we obtained meant. There was software on the computer which identifies possible candidates, but it's hard to narrow down one from a list of hundreds.  There have been lots of conversations with our Mineralogy professor as well as Amanda in how to best choose the right mineral we’re looking at.


The slide for XRD analysis, prepared with Kaolin. We were suppose to make the surface as flat as possible, but we quickly found out that trying to do that was an extremely tedious process!
So, thats kind of where we’re at now--making do with what we’ve got. In the absence of substantial real data Ely and I have been reading a lot of papers to make sense of the diffractograms (thanks for the specificity, Zeb) to try and figure out what exactly is in our samples, but its been a struggle. Amanda suggested that we see if any of the samples we ran through the gamma-spectrometer had meaningful data, and it turns out we have 6 or 7 that did run successfully. I think our plans for the rest of the semester are to continue parsing out the XRD information, even if it's just loose connections / verifications of assumptions and try to analyze the few samples that did make it through Harbin.  I still see a lot of paper reading in our future!
XRD output of one of the samples we ran! This pattern was pretty characteristic of  most of the samples we saw and it is turning out to also be very tricky to work with!


Hi! This is Ely,


This fall has been my first semester in Amanda’s Geomorph lab, and I’ve had a blast learning the ropes from the rest of the lab group, especially from my partner, Marcus. I have joined Marcus in helping him further his Dominica KECK research project. My semester started with some general training on how to perform some of the tasks Marcus and I are responsible for.  These items include operating our gamma-spectrometer, HARBIN; leaching soil samples, and operating the X-Ray Diffractometer (XRD). For a portion of the semester, we ran samples in the XRD, and since then have been trying to decipher the data it produces, which should allow us to understand the composition of the Dominica soil samples. In addition, we leached several samples in order to prepare them for Mae Kate, a recent Obie graduate. She is currently using the samples for her research at University of Vermont. As of right now, Marcus and I are hoping to return to Dominica during winter term to collect more samples, as we believe they could provide great insight as to the before and after effects of a large tropical storm, such as Hurricane Maria, which hit Dominica head-on. I have really enjoyed my time in Amanda’s lab and being able to work alongside a mentor such as Marcus. I have truly learned a lot about the scientific methods used in a lab that is not part of an organized classroom setting, something I have never experienced before.


Thanks for reading!

Ely


Thursday, June 29, 2017

Lab day number 4!

Today was a long day for Team Geomorph.  We started out by doing some GIS/photoshop/abstract-writing, then Kira and I moved on to weighing out our samples and adding hydrochloric acid to them.

Geologists (Kira, above, and Haley, top) hard at work

We took advantage of a delicious free lunch in the lobby after we put the samples in a sonic bath (to keep them mixed while the acid leaches off the coatings of the grains), then went back to work on the computers.  At one point, we had to turn off the heat in the sonic bath since the bottles were starting to deform and smell weird, but after that we were back to work drying out the fine-grained samples!  We centrifuged them to get out some of the water, then scoop out the mushy muddy clay and put it in dishes to go in the oven to finish drying out.


Oh me oh my… “hard rock” people were all over the place today. We received our last batch of
rock buckets/samples yesterday (and just in time). Those of us that needed to finish powdering
rock samples were able to do so. Jessie and Sarah were able to weigh out the powders to prep
them for their acid baths. I also got the rest of my thin sections (Thank you Bill!!!!!) and get to
start doing my point counts tomorrow (1000 points on 11 slides… huzzah!).


Half of my thin sections (I’m really excited about the one with the giant enclave).
Now that all the rock cutting and powdering machine work is finished we get to spend our time
glued to petrographic microscopes and thumbing through different scientific papers that relate to
our projects (happy happy joy joy).
Twinned plagioclase crystals 👿 ...check out that cleavage👿
Everyone has the option to take the day off tomorrow but a few of us are planning on going to
the lab and taking advantage of having fewer people to try and work around in our small
basement lab. There is also a change that the SEM machine will be repaired tomorrow (fingers
crossed)!

~Haley and Katie

Wednesday, June 28, 2017

Union Day 3

With the SEM broken, the petrologists found other ways to occupy their time. Some powdered their rocks to be analyzed for chemical compositions. Some took pictures of their thin sections or did a point count to find which minerals were in their samples. Some read papers about what they're working on. At the end of the day, the rest of our samples from Dominica were delivered, so we have six more buckets (over 200 pounds!) of rocks to prepare to be analyzed over the next few days.


Team Geomorph didn't have a super exciting day either! The past two days have been spent plugging away on the computer, either completing GIS information, photoshopping the clouds out of satalliete imagery or plotting the landslides on the island. We've been eagerly waiting for our samples to arrive from Dominica, so when we got word from Holli that they were in it was a nice change of pace. There are a handful of things we want to do with the actual samples, while on Union's campus we want to begin the leaching process. In order to start that we need our samples to be dry, so at the end of the day Kira, Haley, Cole and I found some washing glasses which could withstand the awesome heat of the oven. Two samples that were fairly dry to begin with took less than an hour to achieve the nice sandy texture we were looking for, so that was a nice surprise and an even better way to end the day with. Well, kind of end the day with, there were four samples that we didn't have enough room for in the oven, so Haley and I went back at 8 to move around dishes that were done with the still damp ones.
The culmination of two days of HARD work


 

First Day of Lab Work at Union


The Keck students begun their first day of lab research at Union College, waking up at 9am to get a tour of the campus and lab facilities that they will be working in for the next two weeks. Students were introduced to the GIS systems, the isotope lab, water table, rock saws, the scanning electron microscope (SEM), rock crusher, Ion Chromatography Systems, lasers, and other wicked instruments.

The water team quickly began to prep all of their samples while the other groups split up. Team geomorph spent the beginning of the day working on their GIS mapping, but were cut short by a rogue professor that took over their lab.

Team Hard Rock spent their day cutting out thin sections of their samples using a rock saw:
They also studied some pre-made thin sections, and learning how to make photomicrographs.

All teams came together later in the afternoon for a safety briefing, and then at the end of the day some students went on an adventure to Walmart to stock up on supplies. It rained and hailed on their journey there:

Video Error....  Sorry Folks there was a great hail video.


Tuesday, June 27, 2017

15th Day

Lab work continues at Union from morning till night for the intrepid Keck crew.

Today the dwarves of the petrology team, in the depths of their underground workshop, cut slices of rocks and powdered rocks to determine whole rock chemistry.
The water team spent the morning preparing and running samples to determine the amount of dissolved inorganic carbon in their water samples.

Syringing 6 mL of water sample to a test tube.

Geomorphologists could be found glued to computer screens in the GIS lab. Marcus perused high and low on the composite satellite image of Dominica made by Haley in search of landslides. 

After a delicious lunch of mac and cheese and pulled-pork sandwiches, courtesy of Union College summer research presenters, some students had the afternoon off. Mazi took this opportunity to get a haircut, others wandered the town in successful search of cheap hot dogs. 

Finally, Dexter and Jackie wrote a blog of their exploits. 



Monday, June 26, 2017

Days 13-14: Travel and relaxation

On Saturday about half our group left Dominica for Union College. The rest of the group had some time to play tourist and relax. A few hung out at Springfield, a few went to find a cliff jumping spot, and a few went to walk on a nature trail.

Taryn, Abadie, Mazi, and I ventured off in search of Chaudiere Pool, which reviews on Trip Advisor claim is one of the best spots to visit in Dominica, with a waterfall and a 30 ft deep pool to jump of rocks into. It was described as being a distance from the road ranging from "right next to it" to "45 min hike". We found the village of Bense and parked when we were told the road was under construction and we had to walk. The walk was about 45 min and other than a minor detour down a driveway, was easy to follow and well marked once we were off the main road. Once we got to the river it took a little looking around to find the pool, which was smaller than we expected. We all enjoyed jumping in and took a total of 13 jumps from the high spot (12-15 ft above the water?) between us during the ~90 min we were there. We also saw two birds that we are pretty confident were parrots. They flew just over our heads across the river between two trees.

Abadie jumping in

Taryn's turn

Mazi takes a go

Amanda leaping in

Before we left Chaudiere Pool we tried to help Holli out by getting some of the andesite that the pool was made out of, but without a rock hammer, we were only able to collect some chips from a fire pit and they turned out not to be very useful. 

Holli took Marcus and Chloe to the Syndicate Nature Trail where they walked a short way up the Diablotin Trail to see if there was rock there. They then went to look for parrots and learn about the flora of the area. They also saw two birds that they think are parrots and definitely heard some parrot calls. Below are some pictures they took.







Sunday the group in Schenectady had a relaxing day visiting the Green Market and hanging out. The rest of us got up super early and spent all day traveling to Union. Now that the sample collection part of our trip is done, we are getting geared up for 2 weeks of lab work.

Friday, June 23, 2017

Day Twelve in Dominica

Beach Day or Flashback Friday, to some of our crazy companions, was an absolute blast! Last week we got sunburned from the long grueling hike up to the boiling lake, but today it was from relaxing in the sun.


Today was the last day in Dominica for half of us, before the first batch of us head to Schenectady, NY to analyze the samples we collected here.  See you all on the other side!!


Dominica Day 11/Shipping Out Samples

Kira and I forgot to post
but that's certainly no reason to mope
Day 11 wasn't very dope
you can tell we're tired, the end is close

Petro people hacked at rocks
chipping them to smaller blocks
Geomorph sieved and shifted
then wrapped their seds to be gifted

When all was finished and shipped away
we still had plenty of the day
to the deck we brought our boredom
and watched It Follows, oh what fun

the end.



Wednesday, June 21, 2017

Day 10 Dominica Keck Project

6/21/17
Today we split into 3 groups. The geomorphology group went to collect water and sediment samples from rivers while another group collected basalt samples and the final group surveyed the stratigraphy at Fond St. Jean. The group looking for basalts traveled northward and through the middle of the island to attempt to get to the south east, because the road leading directly to Petite Savane was destroyed in 2015 by tropical storm Erika. They found 2 outcrops of basalt on the side of the road and collected samples from one of the outcrops. Since the road into Petite Savane was closed, the group got out of the car and hiked to the outcrop to collect samples. The trail was muddy, but passed some cool cows.

Basalt flows from Fond St. Jean

The group that headed to Fond St. Jean spent the morning looking at the stratigraphy along the side of the road and collecting some samples of basaltic ejecta. This material is believed to be some of the most primitive lava deposited on the island. Back at Springfield, these samples were washed and separated from the dirt encasing them and then heated to dry. Different people then spent the rest of the day labeling, cutting down, and packing up samples to be shipped off later this week, as well as meeting with the project directors to discuss individual projects.
Some stratigraphy visible from the road in Fond St. Jean


-Clarissa and Taryn

Dominica Day 9

Day 9 in Dominica - Tuesday 6/20/17

Today was our first official day off in Dominica. Our professors had interviews with local TV stations scheduled in Roseau, so a small group of students (including the two of us) decided to head into Roseau with them to spend the morning and early afternoon exploring. We were able to try some of the local cuisine at a few different cafes and restaurants and explore the various shopping areas throughout Roseau. A view of Roseau from Morne Bruce is included below.



We headed back to Springfield Guesthouse afterwards, and then each student gave a short presentation about their individual project, what kind of work they plan on doing back at Union College, and what the overall significance of the project is. The water and geomorphology groups have generally been separated from the petrology group throughout our time here, so it was nice to get an idea of what everyone's been working on here during our time apart.


- Justin & Sarah 

Monday, June 19, 2017

Day 2^3

We spent Day 8 split into geomorphology/water and petrology groups, all doing our thing and collecting samples.  It was pretty good weather, cool and breezy, but with some pretty dark clouds, thanks to Tropical Storm Bret.  Thankfully, it's supposed to stay south of us.

The petrology group spent our day in the south end of Dominica in a region known as Foundland. The majority of our group collected samples near the beach town of Font Saint John. Those that stayed in Font Saint John broke into two groups. One group collected pumice clasts and basalt from outcrops found along the main road through the town (Fig. 1). The other group measured layers to construct a stratigraphic column of deposits found along the beach (Fig. 2).
 

Figure 1. Walking the road through Font Saint John.


Figure 2. Measuring deposits found along the coast near Font Saint John.
 A few “hard rock” people went to the northern end of Foundland (Fig. 3) to see the outcrops where samples were collected earlier in the week. While revisiting this area, we found a few more outcrops to sample from.
Figure 3. Outcrop in northern Foundland.
 The group that went to northern Foundland returned to Font Saint John around lunchtime. We split up and joined the two groups that were sampling nearby. Those of us that stayed near the coast had the opportunity to chat with some of the locals. They shared some stories of their lives in Dominica and taught us a few creole words.   

Students in the geomorph/water group, hard at work hunting for sand
Meanwhile, team geomorphology/water chemistry sampled 8 locations, this time on the east coast of the island.  And we were on time for dinner!  At each location, we tested and recorded data about the water, sieved sediments to the two size ranges (<63 and 250-850 micrometers), and took lots of notes and pictures.  Some of the highlights include swimming in one of the rivers, learning why Mazi is so obsessed with the hot dog/sandwich question (he’s in debate club so he apparently just likes arguing), and spotting a sign politely requesting cow owners to tie up their cows (upon seeing that sign, Cole jokingly asked if we could steal a cow, but Amanda immediately shot that down).

A sign stating that “ALL COW OWNERS ARE ASK TO TIE YOUR ANIMALS OR SUFFER THE CONSEQUENCES”
At most of the sites, we got in a rhythm and were completely done within half an hour or 45 minutes, but at a few it was harder to find fine enough sand to collect, in which case it took a little longer.  Some of the sites also went faster when it was really easy to get to the river—a few were just off the road and you could casually mosey on down—and it took a little longer when it was more challenging to reach the river—at one of the first sites, we had to climb through a hole in a floodwall to actually get to the water.

Starting our morning off right by scrambling through a hole in a floodwall
In addition to learning about the water, we also learned a little about the island from Pat, who explained that many of the descendants of the indigenous people live on the east side of the island.  She pointed out how the land was slightly different, since they generally farm more than people elsewhere on the island.  At our penultimate stop, she also showed us a little road leading around a bend to a nice view of palm trees and grass overlooking the ocean.

A beautiful ocean view that we enjoyed towards the end of our day
After our geology-filled days, the two groups met back at the guesthouse for dinner (as usual).  The day concluded with some of the best chocolate pudding we’ve ever had, so it was a pretty good day.

Sunday, June 18, 2017

One week In - Dominica Day 7

Hello everyone,
This is Abadie and Marcus here to tell you about day 7 of our time here on the island! After breakfast the group split up into two teams, team geomorph and team petro. Fortunate enough for all you readers, we we're each on different teams so you'll read about everything. 

Team petrology started out the day hunting for enclaves in a quarry on Micotrin, a lava dome in Morne Trois Pitons National Park. We were quite successful, we found a lot and several different types of enclaves that Sarah will be looking at for her project, as well as andesite for Jessie and Abadie to use.
Displaying IMG_5992.JPG
An enclave from the quarry at Micotrin.
After the quarry, we attempted to hike up Micotrin to find more samples, but didn't get very far. The trail was practically vertical, and we were on all fours on the way up climbing over rocks and roots, so we headed back after about ten minutes.
Displaying IMG_5994.JPG
The trail up Micotrin.
We visited two ignimbrites in Roseau valley to find pumice clasts, and we ended our day in the Botanical Gardens in Roseau getting more pumice at the top of a short trail. 
Displaying IMG_6003.JPG
A beautiful ignimbrite in Roseau Valley.
There was a festival going on in the gardens, so we checked that out before heading back to Springfield to relax for the rest of the afternoon.
Displaying IMG_6005.JPG
The view of Roseau from Jack's Walk Trail in the Botanical Gardens.

Team Geomorphology spent the day along the east coast of the island. Our groups goal was to collect sediment sieved to a specific grain size (less than 63 microns and between 250-850 microns) as well as collecting water samples from different rivers and streams. As Holli has been working in this region for years, these locations have been tested and photographed before, so a side project I've taken up is repeat photography; trying to recreate photos that have been taken in previous field seasons and see the changes. We started the day with high hopes of collecting sediment and water samples from 8 different locations, but unfortunately got rained out after site number six. 

Our first stop was at near a grocery store in the town of Portsmouth, which is in the north-eastern section of the island. It was a fast moving stream with large cobbles covering the banks and stream beds, and smaller to medium sized boulders acting as obstructions and creating rapids. This was a very common setting for most of places we sampled at. Other notable things throughout the day included stopping at a site with two large trees uprooted and integrated into the channel, seeing a small hermit crab scurry along the bank and leaving Amanda's camera at one site without realizing it. Its alright though, we figured out that we were missing it fairly quickly though, and were able to go back and grab it.

One of the repeat photography comparisons. Previous years image on the left, todays on the right. There was a noticeable increase in size and frequency of large rocks as well as much faster moving water. 


Overall, it was a fun day, not as exciting as the Valley of Desolation hike or  going through the Sulfur deposits, but interesting and eventful nonetheless!

Saturday, June 17, 2017

6


Welcome to Dominica Day 6, by Jackie Buskop and Dexter Kopas! Fraught with water sampling, gas sampling and rock collecting. After an hour and a half north along the beautiful coast all three cars arrived at the Picard River to collect water samples. 

Dexter, Mazi, Kira, Cole, and Pat ventured bravely down the river to determine factors like temperature, pH, dissolved oxygen content. The rest of us loitered in the shade, argued about the parameters constituting a sandwich (see graphic below) and stretched our legs to recover from the hike (see day 5 blog post). Meanwhile, Team Rock Smash looked at pumice clasts and lithics in a finely laminated pyroclastic flow. After we gracefully piled back into our vehicles, we drove further north up the coast to Fort Shirley where we feasted on our potato filled bread pockets and gazed up at lava domes. 

Inside the fort, an exhibit retold the story of European colonialism in Dominca. For your extended historical knowledge, after the British colonized the island in the early 1800s, they forced groups of indigenous persons to form a slave regiment to protect Ft. Shirley. After much toil and hardship, the regiment revolted against the English control and fought off ships that were sent in to reclaim the fort. In the end, they were set free and everyone lived happily ever after and there were never any problems on the island from this moment forward. (This interpretation of Dominican history has been slightly dramatized.) Also learned about was the Munchineel tree: do not eat its fruits or burn its wood, for you could die from ingestion or inhalation of its noxious fumes!

Whilst enduring our windy car ride up the mountains, Team Sieve vigorously debated whether a hot dog was a sandwich and whether the definition of sandwich depended on structure or filling. (see: is a wrap a sandwich? is a taco a sandwich?) Other food related debates regarding the differences between  broccoli and broccolini and cheese stuffed crust vs crust stuffed cheese ensued.


After our historical stop, complete with ocean view we drove east into the heart of the peninsula of Morne aux Diables to sample the cold fumaroles at Cold Soufriere. Team Water (Mazi and Dexter) took more samples of the boiling pools, while Team Rotten Egg (Jackie and Pat) sampled gas from fumaroles at Nancy's and Eric's pool. Knees weak, arms spaghetti, they could get close enough to the fumaroles to absorb the delicious sulfur fumes, as the magma chamber is deeper than elsewhere on the island, imparting chemicals (pH of 1.4!) but not heat. 

Jackie and Pat using a funnel connected to a Giggenbach flask via a tube. The funnel is held underwater to collect gas that is bubbling up from the fumarole. Gas bubbles through the NaOH that neutralizes the acidic CO2 and H2S and collects in the headspace within the flask.

Next the group split up. Most of Team Rock Smash headed back to Springfield to process samples and get some much needed rest. 

Meanwhile, Justin sampled andesite banded pumices and enclaves from a quarry at Morne Trois Piton. 

Team Sieve and Team Water had a relaxing afternoon of wading in rivers and sieving for sand. They drove down the east coast to sample sediment and water in three rivers emptying into the ocean. Team Sieve will be backtracking erosion rates of the island's larger rivers using Be10 dating. At one river, the delta margin between the river and an estuary could be easily seen. 



After a long day and a late dinner, the Keck troopers were happy to snooze early, as tomorrow will be another long day.