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冰山冲刷揭示了古代风的模式
数千年前搁浅的冰山留下的冲刷痕迹记录了从劳伦泰德冰盖上吹过的风。
来源:Eos杂志说到令人印象深刻的广阔冰冻水域，请考虑劳伦泰德冰盖。 This icy behemoth blanketed much of Canada and parts of the northern United States thousands of years ago and left glacial lakes and icebergs in its path as it retreated.研究人员现在研究了其中一些冰山留下的痕迹，以推断劳伦泰德冰盖运动时的风型。 Understanding such paleowinds can shed light on how ancient expanses of ice influenced global weather patterns, the team suggested in a paper recently published inGeology.
景观中奇怪的战壕
“我开始发现所有这些奇怪的战壕。”
几年前，Sean Grasing 碰巧正在分析激光雷达数据集。 He was using the observations, which reveal the contours of a landscape as if it were denuded of vegetation, to search for small moraines in New York.但他的调查很快就发现了许多不寻常且意想不到的特征。 “我开始发现所有这些奇怪的沟渠，”纽约布法罗大学的地球科学家格拉辛说。
Grasing ended up switching research directions to map those mysterious features, tabulating more than 3,000 of them across parts of Michigan, New York, Pennsylvania, Ohio, Ontario, and Quebec.最长的跨越11公里，但大多数长度只有几百米。它们的深度从一米以下到大约五米不等。
Grasing and his thesis adviser, geologist Jason Briner, concluded that they were looking at scour marks left by icebergs scraping against the bottoms of lakes. The source of all that ice was the Laurentide Ice Sheet, which discharged icebergs and created glacial lakes as it retreated during the late Pleistocene.
有冰，会阵风
今天、明天、明天有风
“现在我们已经在景观中雕刻了证据。”
—Katherine Kornei (@KatherineKornei)，科学作家