(ESH) Effects of Glacial Lake Agassiz on the Climatic History of Minnesota

(ESH) 阿加西冰川湖对明尼苏达州气候历史的影响

• 批准号: 9508216
• 负责人: Herbert Wright
• 金额: $ 7.9万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-15 至 1997-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9508216&HistoricalAwards=false
• 关键词: ESH; Effects; Glacial; Lake; Agassiz

9508216 Wright Glacial Lake Agassiz was a huge lake fronting the retreating Laurentide ice sheet. Its southern and eastern arms in northwestern Minnesota were occupied from about 11,600 to 11,000 radiocarbon years ago, but following a dry period contemporaneous with Younger Dryas interval only the southern arm was occupied, from 10,000 to 9,500 radiocarbon B.P. This proposal aims to evaluate the effects of the cold glacial meltwaters of light 18O on the climate, vegetation, and small-lake limnology downwind on the adjacent moraines by stratigraphic analysis of varved sediments of small deep lakes. analysis of pollen, stable-isotope and trace-element composition of ostracodes, stable isotope composition of cellulose in organic matter, and species composition of ostracode assemblages will be used along with varve counts and AMS radiocarbon dates to establish a dated stratigraphy to correlate with Lake Agassiz phases of expansion and reduction. A site downwind of the eastern arm should show one interval of lake effects, of Lake Agassiz on the climate of the adjacent landscape.

小行星9508216 阿加西冰川湖是一个巨大的湖泊，面对着正在消退的劳伦泰德冰盖。 它在明尼苏达州西北部的南部和东部臂在大约11，600到11，000年前被占领，但在与新仙女木间隔同期的干旱期之后，只有南部臂被占领，从10，000到9，500年B.P.。通过对小型深湖的纹状沉积物的地层分析，探讨了邻近冰碛物下风处的小型湖泊湖沼学。 花粉分析、介形虫的稳定同位素和微量元素组成、有机质中纤维素的稳定同位素组成和介形虫组合的物种组成将与纹孔计数和AMS放射性碳年代沿着用于建立年代地层学，以与阿加西湖的扩张和缩小阶段相关联。 东臂的下风处应显示阿加西湖对邻近景观气候的影响。