Finding Floods

By: Simon Pendleton, WHOI Postdoctoral Scholar

Fortunately, Kingsley was there to keep us on schedule.

While September may be the end of the summer season in upstate New York lake country, it is prime time to go lake coring! Earlier this fall the CRL group took a break from marine excursions to pack up the coring equipment and head inland in search of glacial lake sediments.

Building off of work done back in 2005 by our intrepid leader, Jeff Donnelly, we were on a mission to find evidence for glacial lake outburst floods that originated in northwest New York ~14-13,000 years ago. As the Laurentide Ice Sheet (LIS) retreated northward through New England following the Last Glacial Maximum ~20,000 years ago, meltwater from the ice sheet collected in the topographic depression at the ice margin (a result of the mass of the LIS pushing down on the crust). Of particular interest to this project is the meltwater that collected in northwest New York and modern-day Ontario, forming Glacial Lake Iroquois that was bounded by topographic highs to the south and dammed by the LIS to the north.

Depiction of Glacial lake Iroquois and its drainage through the Champlain lowlands and out the Hudson River Valley during deglaciation (Illustration by Jack Cook, Woods Hole Oceanographic Institution).


However, as the LIS continued to retreat northward, isostatic rebound of the crust and changes to the position of the northern ice margin would change the lake basin shape and open up new flow paths and channels. During the high stand of Lake Iroquois, the retreat of the LIS in northern New York exposed a new flow path that caused catastrophic drainage of Lake Iroquois into what is today northern Lake Champlain before turning south and eventually draining out the Hudson River Valley into the Atlantic Ocean.

Paleoshoreline features (e.g., raised beaches, deltas, and lake sediments) in New York and Vermont suggest that drainage events such as this continued to occur as the LIS retreated northward. What is still unknown is the precise timing of these lake level lowering events which was the goal of the coring excursion this September.


An 1820s farmhouse AirBnB was our base of operations was literally at the end of the road, but not a bad place to work from!

Loading up trusty Truck 30 with the R/V Arenaria, lab manager Nicole, interns Isabella and Phoenix, new postdoc Simon, and of course, field pup Kingsley, we all made the trek up to Gouverneur, NY. Our 1820s farmhouse AirBnB was very pastoral and only a little spooky and (more importantly) placed us in between the lakes we hoped to core. Our objective was to core lakes deep enough to obtain the transition between minerogenic glacial lakes sediments and the overlying organic-rich lake sediments. The hypothesis here is that when each of these modern lakes were part of the larger glacial Lake Iroquois they would have been receiving meltwater and sediment from the LIS and preserving laminated silts and clay. Once the lake level drained and isolated these lakes to their approximately modern configuration, they would have begun to preserve more organic-rich lake sediments. Therefore, if we are able to date the transition between glacial lake sediments and organic-rich lake sediments, that transition should correspond to the lake level lowering event.

(L to R) Phoenix, Isabella, and Nicole are pretty excited that 1) we haven’t sunk the boat, 2) it’s not raining (yet), and 3) we got our first cores!


So out we went to our first lake to set up the vibracore equipment and get our first cores. After a day of knocking the rust of our coring skills, along with some help from local lake residents and the timely arrival of Jeff, we started pulling in cores with organic-rich mud at the top and glacial mud on the bottom! Soon we were becoming an efficient team, and despite a temperamental generator, managed to pull several cores from our first lake, including some larger 12 m ones!


In the end, we were able to core 4 separate lakes, retrieving several cores from each for a total of 21 cores and ~130m of lake sediments. In the end, none of it would have been possible without the awesome CRL research team!

Now that we are back in Woods Hole, Phoenix and Bella have been hard at work splitting the cores. We’ve even started getting a look at some of the glacial to non-glacial transitions:

An example of a transition from glacial (gray much on right) to non-glacial (darker mud on left) sediments (core top to left).

Next up: digging through meters upon meters of mud to find organic material to radiocarbon dates in hope of constraining the timing of the transition; stay tuned!

Additional photos:

Simon tending to the ratchet straps while our new friends recover and secure their kayak to a horse and buggy.


Phoenix’s first time coring, he is pretty excited.


Kingsley is the definition of a ‘road dog’.


Simon (left) and Bella (right) preparing to recover a capped core.


Simon (left) and his assistant Kingsley (right) taking a rock sample from a whaleback.


Dead Storm Hunting: Fiji and Vanuatu

By: James Bramante, PhD student in the MIT/WHOI Joint Program

This blog is cross-posted on the Broader Impacts Group website.

Hills and mangrove forest near Vanua Balavu village, Fiji. Photo credit: J. Bramante


Fiji and Vanuatu are island nations in the tropical South Pacific.

There’s nothing like arctic weather to make you nostalgic for tropical fieldwork. During the past two weeks, temperatures dropped to 5 F (-15 C) in Boston and Cape Cod, and with wind chill it felt like -5 F (-20 C). I had the dubious fortune of bragging to my uncle in Alaska that for once our winter was harsher. Walking 20 minutes to work each way every day gave me plenty of time to wish I was back in Fiji and Vanuatu, extracting the remains of tropical cyclones long past.

Storm Chasing of a Different Kind

Dead cyclone hunting is one of the main activities of the Coastal Systems Group at WHOI. Tropical cyclones, (a.k.a. hurricanes, typhoons) are large, spinning storms that form over the ocean, increase in strength over warm water, and generate large wind speeds and waves that can devastate coastal communities.

Roofs and sand are not the only things moved by storms. These area a sample of the boats thrown up on shore in Port Vila Harbour during Cat 5 Tropical Cyclone Pam. The boats hadn’t been salvaged since the storm hit in March, 2015. Photo: J. Donnelly

In addition to knocking down trees and ripping off roofs, cyclones generate waves that sweep over coastal barriers like beaches, carrying layers of coarse sand into protected bays and lagoons. Without storm waves, only finer mud is deposited in these basins, making the sand layers stand out. Decades, hundreds, and thousands of years later, these sand layers, the only remains of long dead storms, remain preserved under thick mud. By retrieving long cores of sediment, we can identify ancient storms, their frequency, and even their magnitude. We’re the muddier and usually less glamorous cousins of storm chasers.

Jeff Donnelly and Nicole D’Entremont at the beginning of our trip. It’s amazing how much the right pose on the deck of a sailing vessel on tropical seas can improve one’s glamour. Photo: J. Bramante

Fieldwork, Alpine Style

Traveling “light.” Normally our equipment fills half a shipping container. This trip we checked it all onto the plane as luggage. Photo: J. Bramante

In September 2017, we landed on Taveuni Island, Fiji prepared to tackle the field alpine style: fast and light. A lack of funding meant we couldn’t ship our large coring engines across the Pacific, so we made do with a hand-driven percussion coring system. To use this system, we attach a long, empty, aluminum barrel to the bottom of a circular anvil, and then lower it to the sediment surface on a strong rope.

We then use a second rope to raise and then drop a 50 lb “hammer” onto the anvil. The blows from the hammer push the barrel into the sediment incrementally, so that over an hour of back-breaking labor and hundreds of hammer strikes we can push the barrel up to 5 meters (~16 ft) into the sediment. Then the real work begins. A 5-m barrel of sediment only weighs about 46 kg (100 lb), but when it’s stuck 5-m deep in mud it can take hundreds of pounds of force to extract. Without our heavy duty electrical winch, we were forced to extract the barrels with a farm jack, also hand-driven. All of this work is conducted on a floating platform. Normally we use two 20-foot long inflatable kayaks to support the platform, but working alpine-style meant we had to make do with a platform half that size supported by sea kayaks.

A sampling of our makeshift coring platforms from this trip. One positive side effect of alpine-style fieldwork is that you get a chance to iteratively design and test field equipment. Photos: J. Bramante and J. Donnelly

At several sites our attempts to extract the sediment nearly sank our rafts and we had to let the sediment go. That feels a lot like this:


No evil uncles for us though, just gravity and disappointment.


Our poor transducer after TSA attempted to remove it for the umpteenth time. We managed a field repair, but upon returning home we found TSA had severed the cord completely. Photo: J. Bramante

The risks of Alpine-style fieldwork are numerous: lighter equipment breaks more easily, without spares you can’t afford to lose equipment, and lighter equipment means less mud can be retrieved. On this trip our percussion corer broke catastrophically four times, we were forced to abandon three barrel-fuls of mud or risk drowning, tampering by TSA destroyed our most expensive piece of equipment, and by the end of the trip we were too exhausted to function.

However, as with alpine-style climbing, alpine-style fieldwork allows you to move more quickly and achieve more objectives. Over four weeks, 400 km, and two countries we meticulously surveyed ten sites with a sub-bottom sounder (sonar that tells you how much mud is at the bottom) and successfully retrieved mud from all eight sites at which we made the attempt.


Sediment from one of our Vanuatu sites. You can see the remains of at least two storms in three event beds consisting of cobble-sized sediment surrounded by mud. This is one of the most stunning examples of storm deposits I’ve seen. Photo: K. McKeon


The Views

Below is a sampling of the sights at our sites to keep you warm during this frigid winter.

Cobia, Fiji

Cobia is a volcanic caldera within a larger atoll-like reef (Budd reef). You can see layers of cooled lava that constructed the volcanic cone on the rock outcrop on the right. Photo: J. Donnelly


Bay of Islands, Vanua Balavu, Fiji

Limestone pillars covered in shrubs, the “islands” for which the Bay of Islands is named. Photo: J. Bramante


Waves and the tide have cut notches into each of the limestone pillars at water level. Photo: J. Bramante


Emau, Vanuatu

Emau in the distance, an island with a dormant volcano. The bay there is sheltered by a very shallow fringing reef. Photo: J. Donnelly


Port Havannah, Efate, Vanuatu

The northern coastline of Efate Island, with stunning uplifted reef terraces outlined in red. These terraces are the remains of old coral reefs likely left above modern sea level by tectonic uplift. Photo: J. Bramante



Fiji and Vanuatu were beautiful countries, whose residents were incredibly friendly and helpful at every step of our journey. All surveys and sediment extraction were conducted with permission from both federal authorities and local villages at each site. We are especially indebted to Dr. Krishna Kumar Kotra and his students at the University of the South Pacific, Emalus Campus, who helped us reach and extract sediment from our Vanuatu sites while respecting local customs and concerns.

Nicole instructing University of the South Pacific students how to use our sub-bottom profiler, pre-TSA destruction. Photo: J. Donnelly

James Bramante (behind students and farm jack) and Dr. Kotra demonstrating the use of a modified percussion coring system to USP students. Photo: J. Donnelly

Hunting Paleo-Fires in Jamaica


by Dana MacDonald

Students learning how to identify macro charcoal.

The University of the West Indies (UWI) – Mona Campus Kingston Jamaica hosted a two-day workshop on identifying and analyzing macro-charcoal from sediments to characterize past fire regimes on May 3rd and 4th, 2017. Two days were devoted to exploring techniques and research tools from past efforts to reconstruct paleo-fires in New England and Florida, and explored future research possibilities in the Caribbean.

WHOI’s Coastal Systems Group research associate, Dana MacDonald, demonstrates how to subsample a sediment core for charcoal analysis.

The workshop was co-taught by Dr. Michael Burn, Lecturer in Climatology, Department of Geography and Geology, UWI and Dana MacDonald, Research Associate Woods Hole Oceanographic Institution and Research Fellow, Department of Geosciences, University of Massachusetts – Amherst.

The event was attended by about 20 graduate and undergraduate students, faculty, and staff. Lectures and discussions were integrated with lab periods to subsample sediments for charcoal, extraction of samples with sieving,

Students practice their new skills by identifying macro charcoal.

and identifying macro-charcoal and other macro-fossils in sediment samples using
stereo light microscopy. Examples of past research were discussed in the context of their climates, landscapes and sediment records, and students uploaded, troubleshot, and ran a test data set with CharAnalysis, a macro-charcoal analysis software.


The field team carries seismic gear down the beach to survey subbottom sediments in Manatee Bay, Jamaica.

Sediment cores from one of the example sites, a lagoon adjacent to Manatee Bay, St. Catherine Parish, were scanned to identify the utility of using macro-charcoal in these saline back-barrier beach lagoons. These cores may hold a fire record for one of Jamaica’s rarest dry sub-tropical forest types, and additional paleo-ecological records for one of the largest areas of undisturbed sub-tropical dry forest in the Caribbean. The workshop was followed by field work originating from the Port Royal Marine Laboratory UWI to several lagoons at Manatee Bay, scouting for areas to conduct seismic sediment profiling, and reconnaissance of the dry forest of the Hellshire Hills.

Seismic surveying of St. George’s Lake, Jamaica. Dana makes it look easy, even as he holds the instrument off the side of the boat.

Additionally, seismic sediment profiling was undertaken at St. George’s Lake, St. Ann Parish, exploring for a Pleistocene length paleo-climate record for the north-coast of Jamaica to compliment sediment records taken from nearby Discovery Bay and Shark Pond in 2016.

The workshop and field research was supported by the Department of Geography and Geology, UWI – Mona Campus, and the Port Royal Marine Laboratory with the gracious help of Drs. Michael Burn and Suzanne Palmer. Additional support was also provided by the University of Massachusetts – Amherst 2017 Research Support Fund, Associate Dean Sally Powers, and Dr. Jeffery Donnelly of the Coastal Systems Group, Woods Hole Oceanographic Institution. Photos: Dr. Michael Burn, Lecturer in Climatology and Dr. Suzanne Palmer, Lecturer Coral Reef Ecology, University of The West Indies – Mona

In The Trenches

Stephanie Madsen and Aleja Ortiz note stratigraphic changes on Eneko Island in the central Pacific.

Sure, acoustic sub-surface imagery and ground penetrating radar are great. Resistivity sensors and magnetometers can tell us so much. We can learn a lot from X-Ray Diffraction scans and radiography. But often the best way to understand the Earth beneath our feet is just to dig a hole. The digging of holes and trenches is a common practice in field work (as is taking advantage of existing holes and trenches that have been conveniently dug within our research area).


Andrea Hawkes along with Argentine colleagues select sea shells for C-14 dating from a trench wall located over 2km inland of the present day shore line in small coastal town on San Blas Argentina.

A hole lets us analyze the stratigraphy insitu, while a trench lets us track the stratigraphic layers left and right as well as up and down. Seeing how the stratigraphy changes along a trench wall provides increased confidence regarding the conclusions drawn from the interpretation. In a trench, we can record and sample the stratigraphy without concern that it was somehow disturbed by the coring process. Trenches and holes negate the issue of sediment compaction that can result from driving the core barrel into the ground and cause layers to appear deeper and thinner than they actually are.  A simple measuring tape can provide precise depth information with a high degree of confidence (just remember… 0 is the top and we measure down).  A shovel or even bare hands can reveal much of the geologic past.


Chris Maio clears out a drainage ditch for sampling in the Marshall Islands.

We just don’t recommend going in head first…


Jeff Donnelly goes in for a closer look.

A Family Affair

Whether exploring remote wilds, asking questions in our own backyards, or helping out in the lab you’ll find the Donnelly’s are hard at work.

In 2010 Jeff Donnelly’s father, Pat, was fortunate enough to accompany the team to Good News Bay in Alaska as part of a project investigating high latitude barrier beach development


Jeff and his father arrive in Good News Bay

Naturally Jeff’s own children have been getting involved with science and discovery.  Amelia has been spotted in the lab while Nate’s been known to bring home a sediment core or two.

Nate and Aemilia

Aemilia seiving on the left and Nate and Emmy label cores on the right

Skippy Pond_Nate coring)

Nate helps his dad get a core here on Cape Cod

Unalaskan Rodeo

The problem, in the deep and narrow confines of Naginak Bay on Unalaska Island in the Aelutians, was that the anchors kept slipping. A successful coring operation requires that the coring platform stays still and does not drift off station. While high-tech solutions such as dynamic positioning can be used on larger and more expensively equipped vessels, the go-to solution for station keeping is to set three anchors such that the coring platform comes to rest firmly between them. If not set correctly the anchors may slip, the boat may drift, and coring becomes impossible. This was the problem faced by WHOI scientists Dr. Jeff Donnelly, Dr. Andrea Hawkes, and tech Richard Sullivan in Naginak during their 2011 expedition; the third anchor kept slipping. After numerous failed attempts a new plan was devised… lassoing a pinnacle.

Richard ties a very large bowline

Richard ties a very large bowline

Once the stationkeeping problem was resolved (and after Richard got his rowing and rock climbing work out for the day) the team managed to recover numerous 9m long cores from the base of the bay. These cores contained a high resolution storm record that can help us better understand how frequently high energy storm events in the North Pacific have occurred over the past several thousand years.

Everything Should Be Waterproof


On a recent field expedition to the remote western end of Kwajalein Atoll in the central Pacific, the team encountered a different sort of problem than what they’re used to.  There was no safe place for the boat to land.  The shallow reef flat and heavy surf prevented the 50′ boat supplied by the US Army base on Kwajalein from getting close to shore or dropping anchor.  This problem, while unusual for a group used to operating off of shallow draft vessels in protected coastal waters, had been anticipated.  The gear was loaded into water tight Pelican cases, dry bags, wrapped in plastic bags, and strapped to a kayak.  The team then donned masks, snorkels, and flippers and swam in through the surf towing the gear behind them.

Fortunately the gear (and personnel) all made it ashore intact, and after taking a few minutes to dry off and collect themselves, it was time for the team to get to work.


Jimmy Bramante (center) and Richard Sullivan (left) tow the ground penetrating radar across Ebadon Island at the extreme Western end of Kwajalein Atoll. Mollie McDowell (right) maps the topography with the high precision differential GPS. Photo credit: Charlotte Wiman

Hole in One

hole-in-oneWHOI geologist Jeff Donnelly and research assistant Richard Sullivan recently joined Texas A&M University at Galveston (TAMUG) geologist Pete van Hengstum and undergraduate student Tyler Winkler in collecting cores from Thatchpoint Bluehole. It is thought that blueholes form when rising seas flood a sinkhole, formed when limestone bedrock is dissolved from below by groundwater and collapses. The team collected a continuous, nine-meter (30-foot) sediment core from the bluehole as part of their efforts to construct a record of the frequency and intensity of tropical cyclones in the western Atlantic. (Photo courtesy of Pete van Hengstum, Texas A&M University)

Climate Time Machine

time-machineJimmy Bramante, a graduate student in the MIT-WHOI Joint Program, collected a core sample from an Atlantic white cedar tree in Cape Cod National Seashore recently. Tree growth is often affected by variations in climate, including precipitation and temperature, which is recorded in recorded in the width and composition of tree rings in many species, particularly Atlantic white cedar. Bramante was part of a team helping fellow graduate student Jessie Pearl collect the core samples as part of Pearl’s work to construct a climate history of the Northeast. (Photo by Jessie Pearl,Woods Hole Oceanographic Institution)

A Stormy Past

stormy-pastnew study led by WHOI scientist Jeff Donnelly found that intense hurricanes frequently pounded Cape Cod during the first millennium. Donnelly (in orange shirt), accompanied by Stephanie Madsen (left), Richard Sullivan (center), and Brecia Douglas (right) collected sediment cores from Salt Pond in Falmouth, Mass. Analysis of the cores showed evidence of 23 severe hurricanes that hit New England between the years 250 and 1150—the equivalent of a severe storm about once every 40 years on average. (Photo courtesy of Richard Sullivan, Woods Hole Oceanographic Institution)