Lamont Weekly Report, January 11, 2019

    As this week draws to a close, the partial shutdown of the federal government –­ including most federal science agencies – is three weeks old, and by tomorrow the shutdown will become the longest in U.S. history ( When the political impasse preventing the reopening of shuttered departments and agencies will be resolved is anyone’s guess. Some of the consequences of the shutdown for scientists at federal agencies were described in yesterday’s issue of Nature ( Impacts of the shutdown are starting to be felt at Lamont in the form of delays in proposal funding decisions. As you learn of other specific impacts that affect Observatory programs and plans, please let the Directorate know.

    In the meantime, scientific progress at Lamont this week continued apace.

    Wally Broecker recently completed an invited book on CO2: Earth’s Climate Driver, as part of the Geochemical Perspectives series published by the European Association of Geochemistry ( Elizabeth Clark wrote, “Wally started writing it last January while in Arizona. It was put online in November, with hard copies available in early December. This concise textbook was written from conception to finish in less than a year.” 

    Science Advances last week published as its cover article a paper coauthored by Gisela Winckler and Pratigya Polissar reporting that a marine sediment core off West Africa records a strong correlation over the past 240,000 years between variations in dust deposition and changes in summer insolation on precessional timescales, i.e., periods of about 20,000 years. The study, led by former Visiting Scientist Charlotte Skonieczny now at Université Paris-Sud, differed from earlier analyses of a core from the same region by the use of 230Th normalization to more clearly constrain dust sedimentation rates. The discovery by Charlotte and her colleagues that the precessional cycle that governs West African monsoon strength also controls dust emissions contrasts with the conclusion of the earlier studies that the sedimentation rate off West Africa has been controlled for the last few million years by the 100,000-year glacial–interglacial cycle. Findings from the new study also demonstrate that variations in low-latitude Saharan dust emissions do not do not follow those for high-latitude dust emissions, which change more strongly on glacial–interglacial timescales.

    The second in the Earth Institute’s Tools of the Trade web series “that brings you inside the labs of Earth Institute scientists” was devoted to Heather Savage and Lamont’s Rock and Ice Mechanics Lab ( The story, posted late last week, focused on the lab’s Triaxial Deformation Apparatus and its application to experiments designed to understand the physics of faulting.

    Jennifer Lamp is in Antarctica this week finishing the first field season of a study she has been conducting with Jörg Schaefer on weathering and erosional processes in the McMurdo Dry Valleys. Jen wrote yesterday, “We had a three-person, all-female field team (with Missy Eppes, from the University of North Carolina, Charlotte, and Kate Swanger, from the University of Massachusetts, Lowell) and completed the bulk of the work at the field site right before Christmas. The other members of the team left Antarctica at the end of December, and I'm at McMurdo Station completing weekly helicopter-supported trips back to the site to download data and do any required maintenance until February. The field season went very well: we collected 65 rock samples for cosmogenic surface exposure dating to investigate short- and long-term erosion rates, and we deployed acoustic emission sensors on four boulders to track real-time internal rock microcracking and weathering. I'm scheduled to be interviewed by The Antarctic Sun, Antarctica's online newspaper, about the project later today.”

    On Wednesday, Kevin Krajick circulated to everyone on campus a request for information on upcoming fieldwork. Once a year, Kevin puts together a web article describing all major field expeditions planned by Lamont and other Earth Institute researchers, as a guide to journalists, potential donors, professional colleagues, and the general public. As last year’s summary illustrates (, the guide provides a compelling annual snapshot of what makes us an Earth Observatory, and the different expeditions each year illustrate the changing focus areas of current research. I encourage all of you who have fieldwork planned for the coming year to let Kevin know your plans soon so that your work will be included.

    Yesterday, Christine McCarthy learned that Alexandra Rivera, a high-school student who worked with her in the Rock and Ice Mechanics Lab, was named one of 300 top scholars in the Regeneron Science Talent Search ( Christine wrote, “[Alexandra] contacted me directly and worked independently in the lab during the summers of 2017 and 2018 on a project constraining the effects of entrained debris on the elastic, viscous, and grain growth properties of ice, with application to glaciers. She presented at AGU in each of the last two years and was a pleasure to have in the lab. I’m very happy for her.”

    Tomorrow morning, the remaining section of the old Tappan Zee Bridge will be explosively demolished ( May all of you with a view of the bridge enjoy the show.