Staff Directory

Tess is a PhD student in the Department of Earth and Environmental Sciences. Her research involves reconstructing past ice sheet chronologies and climate variability using surface-exposure dating and geomorphic mapping.

Sandra M. Braumann is a Ph.D. candidate based in Vienna, Austria. She is enrolled in a doctoral program named “Transitions to Sustainability” centered at the University of Natural Resources and Life Sciences (BOKU) and is co-supervised by Joerg M. Schaefer. Sandra holds a Master’s degree in Civil Engineering and Water Management and works at BOKU’s Institute of Applied Geology. Since 2014, Sandra has repeatedly visited Lamont’s Cosmogenic Isotope Group and has been taught the extraction of cosmogenic nuclides from rock samples. During her Master’s Program, she was engaged in a project, which aims to generate a chronology of the Pleistocene terrace staircase in the Vienna Basin. The application of isochron burial dating using the isotope pair 26Al and 10Be allowed to assign an absolute age to one of the terrace bodies identified in the Vienna Basin. For her Ph.D., Sandra has switched to higher elevations and to younger time scales. She now focuses on the reconstruction of Holocene glacier fluctuations in the Austrian Alps. Geomorphological mapping combined with low-level 10Be surface exposure dating is applied to former ice margins and elucidates glacier change on the geological time scale. This long-term record is complemented with information from historical sources and instrumental time series, which reflect glacier evolution throughout the past centuries and decades. This approach allows insights into natural climate variability during the past 11,700 years. Glacier and climate reconstructions are instrumental for placing the ongoing man-made warming trend into a long-term perspective and for communicating the magnitude of anthropogenic impact on the climate system.

Quaternary surficial geologist, paleoclimatologist, and geochemist whose main interests rest in understanding centennial- to millennial-scale changes in ice sheets and glaciers, assessing the climatic driving mechanisms behind these changes, and understanding how these ice masses shape the landscape. I specialize in using cosmogenic isotopes (in situ ¹⁰Be, ¹⁴C, and ²⁶Al), combined with more traditional field-based approaches (stratigraphy, lake sediments, radiocarbon dating) to develop robust chronologies of glacier change.

After obtaining a B.A. summa cum laude from SUNY Buffalo (1992), I earned an M.Sc. at the University of Maine-Orono and a Ph.D. at the University of Colorado-Boulder. After a short stint as a Research Associate in Boulder, I was a Postdoc at the University of Wisconsin-Madison, University of Edinburgh (Royal Society of London Postdoctoral Fellow), and at LDEO. Since 2006, I have been at LDEO. I was elected a Fellow of GSA in 2019.

Studying the impacts of these cryosphere processes on society, and creating multi-disciplinary networks to develop cross-cutting ideas how to respond to, how to find solutions to these paramount climate-related challenges, has become a recent focus area of Schaefer’s work. Schaefer loves to teach science, and is leading the development of the new ‘Climate Science Major’ program at Columbia together with Prof. Suzana Camargo and the DEES curriculum committee. This program consists of three coordinated Climate Science Majors, one within DEES (‘Climate System Major’), one shared with the ‘Sustainable Development’ program (‘Climate and Civilization’) and one (‘Climate Physics and Chemistry’) shared with the department of ‘Applied Physics and Math (APAM)’. Schaefer is actively engaged in Justice, Equity, Diversity and Inclusion efforts in US Geosciences, as well as in anti-harrassment and anti-bullying campaigns within the US science community.

Schaefer earned his Ph.D. in 2000 from the Swiss Federal Institute of Technology (ETH) Zurich, his thesis awarded with the ETH medal prize. He was a postdoctoral researcher at ETH before joining Lamont as a postdoctoral research fellow in 2001.

I am a glacial geomorphologist, paleoclimatologist, and geochemist driven to understand how glaciers interact with climate. My research focuses on how glaciers have responded to past climate changes over long timescales. To do this, I reconstruct glacier chronologies using glacio-geomorphological mapping and cosmogenic-nuclide exposure dating. I also investigate the climatic drivers of past glacier changes using additional climate proxies and collaborations with glacier and climate modelers

I completed my PhD at Aix-Marseille University – CEREGE (France), where I studied the paleoglaciers of the Kerguelen Archipelago (49°S, 69°E) and reconstructed paleoclimatic conditions since Marine Isotope Stage 3. I am also interested in Late Pleistocene and Holocene glacier evolution in various regions, including the Greater Caucasus, southern Greenland, Nepal, and the European Alps.

During my postdoctoral research at LDEO, I am expanding my expertise by integrating a new methodological approach that utilizes multiple cosmogenic nuclides (e.g., ³⁶Cl, ¹⁰Be, ²⁶Al, and ⁴¹Ca). This approach allows me to analyze subglacial materials beneath the Greenland Ice Sheet to constrain past periods of burial and ice-free conditions in Greenland.

I am a geomorphologist and geochemist with interests in polar surface processes. My research focuses on the mechanisms and rates of rock breakdown in extreme, hyper-arid environments like Antarctica, and the fluctuations of ice sheets and alpine glaciers. I employ a combination of field-based methods (acoustic emission monitoring, micrometeorological monitoring) and numerical methods to determine the processes responsible for rock weathering in the Dry Valleys of Antarctica. I use cosmogenic nuclide surface exposure dating techniques to determine rock erosion rates, and to date glacial deposits in Antarctica and the Arctic. My primary cosmogenic tool is the noble gas He-3, but I also make use of the radioisotopes C-14, Be-10, Al-26, and Cl-36. I received my BSE in Civil & Environmental Engineering from the University of Michigan, my MS in Mechanical Engineering from Virginia Tech, and a PhD from Boston University in Earth Science. I began at LDEO as a postdoc in 2016, and am currently an Associate Research Scientist.

Jacob is a glacial geologist, paleoclimatologist, and geochemist with expertise using cosmogenic isotopes to reconstruct past ice sheet extent and behaviour. Driven to understand the stability of ice sheets and their contribution to sea-level change, his research focuses on ice sheet and glacier responses to changing climate, permafrost processes and landscape evolution. He received his PhD from the University of Otago where he was a Sir Robin Irvine Scholar.

Carly Peltier is a Ph.D. candidate interested in glacier and climate changes of the past, present, and future and their impacts on society. Her dissertation work focuses on reconstructing the timing and character of advances of the Patagonian Ice Sheet during the last few glacial cycles. Her main tools are cosmogenic exposure dating and geomorphic mapping, but she also incorporates information from sedimentary records, historical records, and glaciological models.

Benjamin Keisling is a postdoctoral fellow. He completed his PhD in Geosciences at the University of Massachusetts (2020) and his B.A. in Physics at Saint Olaf College (2013). He uses geochemical data coupled with numerical models to understand how the ice sheets in Greenland and Antarctica responded to past climate change. He is a member of the Greendrill project. For the last few years, he has served as a lead organizer for LGBTQIA+ events at the American Geophysical Union’s (AGU’s) Fall Meeting. As a graduate student, he co-founded the BRiDGE program to address issues of diversity, equity and inclusion (DEI) at University of Massachusetts, Amherst (USA). He also serves as a mentor to diverse undergraduate students through the STEMSEAS program and is co-PI on the All-ABOARD project funded in October 2020. Keisling is a member of the AGU’s DEI Advisory Committee and co-chairs the Lamont DEI Task Force.

Allie is a postdoctoral scholar in the Lamont Cosmo Lab, addressing questions of ice sheet stability and subglacial processes using cosmogenic-nuclide techniques.