Written by Associated Press on December 12, 2020 JACKSON, Wyo, (AP) — When Darren Larsen pushed off in a packraft into Delta Lake four years ago, he expected that he would probe down a few feet into sediment produced by seven or so centuries of glacial runoff. His metal probe, instead, kept sinking and sinking. The paleoclimatologist and Occidental College professor was after the deposited sludge and silt to let him understand the Teton Glacier, which grinds over the gneiss and pulses sediment-laden meltwater into Delta Lake each spring and summer. It amasses in layers under the emerald waters, hinting at the history of glacial activity in aptly named Glacier Gulch.