Chronologies and mechanisms of last glacial loess deposition in the Central Lowlands of North America

北美中部低地末次冰期黄土沉积的年代学和机制

• 批准号: 1637481
• 负责人: Jessica Conroy
• 金额: $ 34.96万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1637481&HistoricalAwards=false
• 关键词: Chronologies; mechanisms; last; glacial; loess

This project will advance understanding of windblown silt (loess) deposition during the last glaciation across Midwestern North American landscapes. Loess deposits are a vital ingredient to the region's rich agricultural soil and, with embedded fossil snails and ancient soils, are important paleoclimate archives. However, Midwestern loess remains poorly dated and disconnected from other climate and glacial records, limiting our understanding of the timing and drivers of loess deposition. New radiocarbon chronologies will relate deposition rate variations to past changes in sediment sources, climate, and ice lobe fluctuations in the Great Lakes region from ~ 25,000 to 18,000 years ago. This research will improve understanding of regional paleoclimate records and atmospheric dust budgets during this last glacial period. An interactive module on the Pleistocene Illinois landscape for an after-school enrichment program, STEAM (Science, Technology, Engineering, Arts, and Math), will introduce these important deposits to local students. New, high resolution radiocarbon chronologies of loess, coupled with U-Pb zircon dating and trace elemental analyses of loess and glacial tills will provide detailed sediment sourcing history. Stable oxygen and carbon isotope analyses of snail shells, along with species assemblages and stable oxygen isotope forward modeling, will aid determinations of the climatic context of changing loess deposition rates. Comparing these deposition rates with the timing of regional ice lobe fluctuations will permit better understanding of the relationships among glacier movement, climate, glacial sediment supply, and downwind loess deposition.

该项目将促进对末次冰期期间横跨北美中西部景观的风吹淤泥（黄土）沉积的理解。 黄土沉积物是该地区肥沃农业土壤的重要组成部分，并与嵌入的化石蜗牛和古老的土壤，是重要的古气候档案。然而，中西部的黄土仍然年代不清，与其他气候和冰川记录脱节，限制了我们对黄土沉积的时间和驱动因素的理解。新的放射性碳年代学将把沉积速率变化与五大湖地区25,000年至18,000年前沉积物来源、气候和冰瓣波动的过去变化联系起来。这项研究将提高对末次冰期区域古气候记录和大气尘埃收支的理解。关于更新世伊利诺伊景观的课后富集计划，蒸汽（科学，技术，工程，艺术和数学）的互动模块，将向当地学生介绍这些重要的存款。新的，高分辨率的黄土放射性碳年代学，再加上U-Pb锆石定年和微量元素分析的黄土和冰碛物将提供详细的沉积物来源的历史。 蜗牛壳的稳定氧和碳同位素分析，沿着物种组合和稳定氧同位素正演模拟，将有助于确定黄土沉积速率变化的气候背景。将这些沉积速率与区域冰瓣波动的时间进行比较，将有助于更好地了解冰川运动、气候、冰川沉积物供应和顺风黄土沉积之间的关系。

项目成果

Episodic deposition of Illinois Valley Peoria silt in association with Lake Michigan Lobe fluctuations during the last glacial maximum

伊利诺伊州谷皮奥里亚淤泥的间歇性沉积与末次盛冰期密歇根湖波瓣波动有关

• DOI: 10.1017/qua.2017.66
• 发表时间: 2018
• 期刊: Quaternary Research
• 影响因子: 2.3
• 作者: Nash, Thomas A.;Conroy, Jessica L.;Grimley, David A.;Guenthner, William R.;Curry, Ben Brandon
• 通讯作者: Curry, Ben Brandon

Last glacial maximum ecology and climate from terrestrial gastropod assemblages in Peoria loess, western Kentucky

• DOI: 10.1002/jqs.3206
• 发表时间: 2020-05
• 期刊: Journal of Quaternary Science
• 影响因子: 2.3
• 作者: D. Grimley;R. Counts;J. Conroy;Hong Wang;S. Dendy;Catherine B. Nield

Detrital zircon geochronology and provenance of Pleistocene loess and contributing glacial sources, midcontinental USA

美国大陆中部更新世黄土和冰川来源的碎屑锆石年代学和物源

• DOI: 10.1016/j.quascirev.2021.107201
• 发表时间: 2021
• 期刊: Quaternary Science Reviews
• 影响因子: 4
• 作者: Dendy, Sarah N.;Guenthner, William R.;Grimley, David A.;Conroy, Jessica L.;Counts, Ron C.
• 通讯作者: Counts, Ron C.