West Antarctic Ice Sheet Microstructures


Research Team Update for 2016

The VeLveT Ice Team is headed back to Antarctica this winter (2016) for their second field season. The membership of the team has shifted a bit, and they don’t have PolarTREC teacher Yamini Bala with them this year, so they are continuing a blog on SquareSpace here.

What Are They Doing?

Snow Drifts on the West Antarctica Ice Sheet (WAIS), AntarcticaSnow Drifts on the West Antarctica Ice Sheet (WAIS), Antarctica The research team studied the microstructure of ice crystals on the West Antarctic Ice Sheet (WAIS). As the research title of their project implies, "VeLveT Ice", the team is researching what happens at the small scale of individual ice crystals that ultimately affect the large flow patterns in an ice sheet. The group is therefore studying the link between crystal properties, ice flow, and climate history because the crystal structure retains a memory of past climate which is recorded differently than "normal" ice core analyses. Ice crystals grow, rotate, and recrystallize with time and flow in an ice sheet. The rate at which each of these processes occurs depends on the temperature, state of stress, and impurity (e.g. dust, ash or salt) content of the ice. The orientation, texture, size and shape of the crystals in a given block of ice evolves through time, but also "remembers" past temperature and flow. Many scientists have observed that these microstructural properties vary with depth in an ice sheet and climate history. For example, ice from glacial time periods typically has smaller crystals, higher impurity content, and stronger fabric than ice from interglacial time periods. These microstructural properties also affect how the ice flows—ice in an ice sheet is far from a homogeneous substance and variations in properties on the small scale can affect large-scale flow patterns.

This project specifically investigated the ice microstructure, impurity content, and ice-flow patterns in relation to climate history for the ice near the West Antarctic Ice Sheet (WAIS) ice core site, using a combination of borehole logging, modeling, and thin section analyses. This work was the first to combine two novel advanced techniques for studying the relationship between ice microstructure, deformation, and climate history. More information about the project can be found here.

Where Are They?

West Antarctica Ice Sheet (WAIS) Divide Galley, AntarcticaWest Antarctica Ice Sheet (WAIS) Divide Galley, Antarctica The team flew from McMurdo, Antarctica to the West Antarctic Ice Sheet (WAIS) Divide drill site on a Hercules LC-130 airplane. The WAIS divide sits on top of 3,485 meters of ice, thicker than 9 Empire State Buildings stacked on top of one another! The WAIS is classified as a marine-based ice sheet, meaning that its bed lies well below sea level and its edges flow into floating ice shelves. The WAIS is bounded by the Ross Ice Shelf, the Ronne Ice Shelf, and outlet glaciers that drain into the Amundsen Sea. While on the Ice Shelf the team members slept in tents and traveled by foot, on ski, or by snowmobile to field sites within 2 km of their base camp.


Flag Planting
Apologies for the long gap between posts, everyone! Between fieldwork and traveling, we had very little technology access for weeks. So here is a long overdue update!! The Velvet Ice team left Antarctica at the end of January. True to form, our departure was an adventure! We all ended up getting split up and leaving the continent on different flights, spanning several days! Rachel made it out first, and Tiffany was last to leave the ice. Where are they now?? After the expedition, each team member went their own way. Rachel Rachel left Antarctica and went straight back home to begin her...
Power line
Science on the Ice The last section of camp is the area where most of the science at WAIS Divide has taken place. It consists of the Arch and two tents. This area is the farthest from town, about a quarter mile walk along the power lines. When navigating in hard-to-see conditions, it is easiest to follow the lines from town (far right) to the Arch and two science tents. The Arch The Arch was constructed in 2005-06 to house the drilling equipment for extracting the WAIS Divide Ice Core. There are two sides to the huge metallic structure – the drilling side and the core-handling side. On...
WAIS in doodoo
All about the WAIS (not the treble)! The Science of Wais Divide About 11-12 years ago, a group of scientists, including Erin Pettit (my lead researcher for Velvet Ice), first came to scope out the site for drilling a WAIS Divide ice core. An ice core is basically a round column of ice that is extracted by drilling it out of a larger ice body, like an ice sheet, glacier, or sea ice mass. For those of you who think in medical terms, an ice core is basically like a long needle biopsy of an ice sheet. To extract an ice core, a drill is inserted into the ice to bring up a thin, round column...
Frozen food
The Paleo-Climate Record The neat thing about ice is that it is one of nature's best preservatives. Think about your refrigerator at home... we put food in the fridge and keep it cold because it lasts longer, right? We put food in the freezer and keep it frozen because it lasts way longer. If you buy fresh vegetables, they will last a couple of days outside, a week in the fridge, or months in the freezer. Photo credit: Jason Depolo Now imagine putting something in a place so cold that ice does not melt for 68,000 years! It would practically last forever! That is basically what has...
Snow pit
All about the WAIS (not the treble)! Stratigraphy In the summer at WAIS Divide, temperatures hover around -10C/14F, more or less. In the winter here, temperatures drop down to -50C/-68F. At temperatures that low, it is actually too cold to snow! So most of the snow that falls in Antarctica actually falls during the summer months here. The solar radiation on the top layer of snow during the summer and over the fall (as the sun rises and sets) causes a metamorphosis in the ice crystals just under the surface. This, along with wind, temperature changes, the loss of sunlight over the winter,...

Expedition Resources

Project Information

30 November 2014 to 24 January 2015
Location: West Antarctic Ice Sheet (WAIS) Divide
Project Funded Title: Collaborative Research: VeLveT Ice - eVoLution of Fabric and Texture in Ice at WAIS Divide, West Antarctica

Meet the Team

Yamini Bala's picture
Chicago, IL
United States

Yamini Bala teaches by engaging students in urban agriculture and problem-based learning in order to solve the challenges of food insecurity, obesity, and diabetes that disproportionately affect the school community. She is currently completing her MS in education at Northwestern University, and has a MA in conservation and community development from Future Generations Graduate School. As an undergraduate at Pomona College, majoring in environmental science, Yamini spent a semester abroad studying comparative ecology in Ecuador.

Her experiences there fostered a passion for traveling, learning languages, and exploring diverse cultures and ecosystems. For much of the following decade, she studied and worked in over 20 countries around the world, while maintaining a home base in Detroit, Michigan where she was engaged in non-profit youth programming and urban agriculture. In her spare time, Yamini enjoys reading, gardening, music, and meditation.

Erin Pettit's picture
University of Alaska Fairbanks
Fairbanks, AK
United States

Dr. Erin Pettit is an Assistant Professor of Geophysics at the University of Alaska Fairbanks. With her interest in landscape patterns and fluid dynamics, glaciology allows Dr. Pettit to combine a background in mechanical engineering with her love of the high mountains and her interest in contributing to questions of climate change and sea level rise. Her research emphasis is in ice dynamics, ranging from the relation between ice crystal microstructure, climate history, and ice flow near ice core sites to the fast flowing calving glaciers and ice shelves as they respond to modern climate change.

In addition to working in Greenland, Alaska, British Columbia, and Washington State, she has been on eight research expeditions to remote field sites in Antarctica; for five of these she was an expedition leader. Dr. Petitt also loves teaching. As a graduate student, she developed the Girls on Ice program, an inquiry-based wilderness field experience for teenage girls that challenges them physically, intellectually, and in leadership. As a faculty member, she has developed a hands-on inquiry-based undergraduate course "Ice in the Climate System" that has students collecting lake ice cores on campus, running their own climate models, and teaching first graders about ice sheets.

Rachel Obbard's picture
Darmouth College
Hanover, NH
United States

Dr. Rachel Obbard is an Assistant Professor at the Thayer School of Engineering at Dartmouth College. She is a materials scientist with an educational background that spans both science and engineering and research experience in areas ranging from nanostructured thin films to the microstructure of ice. Her broad interest lies in the structure of materials, especially porous or multiphase ones, and in cross-disciplinary ways to analyze and characterize microstructure. Dr. Obbard's current research interests include ice and snow, the conservation science of cultural artifacts, and materials in sports. In her cryospheric work, she specializes in sea ice microstructure, ocean-ice-snow-air interactions, and the evolution of microstructure in ice sheets and glaciers.

Dr. Obbard holds a BS in Engineering Physics from the Colorado School of Mines, an MS in Materials Science and Engineering from the University of New Hampshire, and a PhD in Engineering from Dartmouth College. She worked as a postdoctoral fellow for the British Antarctic Survey, where she first began to study sea ice and ocean-ice-air interactions. When not studying snow and sea ice with her graduate and undergraduate students, she teaches courses in materials in sports equipment at Dartmouth and snowboarding at a local ski resort.

Tiffany Green's picture
University of Alaska Fairbanks
Fairbanks, AK
United States

Tiffany graduated from the University of Alaska Fairbanks in 2014 with a BS in Geoscience-Geophysics with a minor in Mathematics. She has been assisting with various research projects in the Arctic and Antarctic for 3 years. The polar and alpine regions have been a particular interest to her during her undergraduate career. She hopes to continue on to a Master's program in polar and alpine climate change after taking some time off to travel, work, and refine her interests. This season with the Velvet Ice Expedition will be her first of what she hopes will be many more experiences in Antarctica.

In her spare time Tiffany loves to read, hike, play board games with friends, and hang out with her pets and loved ones.

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Latest Comments

That is great, Pat. I hope you've been able to follow along with the expedition through the journals!
Hi Auntie A, sorry for the long gap in posts. I wasn't able to post because of technological access issues during travel, but I'll be posting an update shortly. Thanks for your continued interest!!
HI Yamini and Team members. Haven't heard from you all in the entire month of February so just hoping to hear back soon a report on how you are doing and your current activities. T
Would like to read about your experiences in Antartica
Thanks! Yes, you can tell the age of ice from looking at its layers, and an ice core is one way to dig into and see the many annual layers of the ice sheet!