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When an ice sheet overlaps a lake’s catchment basin, the water flowing into the lake leaves a layer of minerals on the lake floor.The grey lakes are those still receiving mineral-laden water from the ice sheet.New radiocarbon dating results from tufa at the margins of Tabernacle Hill as part of this study have solidified key aspects of the exposure history at both sites.Both sites have well-constrained exposure histories in which factors such as potential prior exposure, erosion, and shielding are either demonstrably negligible or quantifiable.Pairing that information with mapping of each catchment basin under the current ice sheet, they can reconstruct the changing size of the ice sheet over time.Ice sheet modelers will then use that data to gauge sea-level rise tied to the melting Greenland ice sheet through history.He’s in a leader in all of these different fields.” How sensitive are ice sheets?
This new project is going to try to figure out how small the ice sheet was and how much its melting contributed to sea level rise.” Blue lakes and black lakes When you look at aerial photos of Greenland, you’ll notice lakes near the edge of the ice sheet that are either grey/blue or black.
By comparing the fast-decaying carbon-14, which has a half-life of about 5,730 years, and much slower-decaying beryllium-10, with a half-life closer to 1.4 million years, they can also tell if the rocks were exposed in the past, covered by an ice sheet, and re-exposed. Joerg Schaefer, who heads the Cosmogenic Nuclide Group at Lamont, puts Young’s skills and accomplishments into perspective: Young was hired at Lamont to bring in Arctic glacier and geology expertise that is normally found well above his career level, and he has lived up to the challenge, Schaefer said.
Young currently runs the highly complicated carbon-14 lab, one of only a few such labs in the world.
Young saw those lakes and recognized a new way to measure the history of the expanding and retreating Greenland ice sheet.
He is currently co-leading a four-year project, financed by the National Science Foundation, that will use sediment cores from those lakes to determine when their catchment basins were covered by ice.