Collaborative Research: Elucidating the Nature, Causes and Climate Importance of the Mid-Cenozoic Loess in the Western USA

合作研究：阐明美国西部中新生代黄土的性质、成因和气候重要性

• 批准号: 2114166
• 负责人: Majie Fan
• 金额: $ 32.38万
• 依托单位: University of Texas at Arlington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114166&HistoricalAwards=false
• 关键词: Collaborative; Research; Elucidating; Nature; Causes

Loess deposits consist of fine-grained, windblown sediments and contain critical information about continental aridification processes that are key to understanding biotic evolution and climate change. This project integrates field data collected from loess deposited ~37-30 million years ago in Wyoming, Nebraska and Montana, laboratory analyses, and paleoclimate simulations to understand the nature, causes, and paleoclimatic importance of these loess deposits. The research will advance STEM diversity by supporting a two-day GEOCAMP for historically underrepresented high-school students from east Texas. In addition, this project will promote further development of the high-resolution Community Earth System Model to be used to better understand ancient climate changes. This project will include field sedimentological observation and lab analyses of bulk sediment and quartz grain-size, quartz surface morphology, detrital and high-precision zircon U-Pb geochronology to study the ancient loess deposits in Wyoming, Nebraska and Montana, USA. These proxy data will constrain the extent, timing, pattern and characteristics of the loess; and determine sediment provenance and sediment recycling mechanisms. These proxy data will be integrated with a coupled atmosphere-land model to simulate changes of regional climate and vegetation induced by topography changes, global climate cooling, glaciation and shoreline regression to understand the cause and climate significance of the loess. In additional to gaining fundamental understanding of the loess deposits, the project will shed light on 1) the influence of climate change on biotic evolution at the Eocene-Oligocene transition (~34 million years ago); 2) the validity of different models of surface uplift in the western USA; and 3) the potential positive climate feedback of enhanced mineral dust emissions on global cooling at the transition.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

黄土沉积物由细粒、风吹沉积物组成，包含有关大陆干旱过程的重要信息，这些信息对于了解生物进化和气候变化至关重要。该项目整合了从约 37-3000 万年前怀俄明州、内布拉斯加州和蒙大拿州沉积的黄土收集的现场数据、实验室分析和古气候模拟，以了解这些黄土沉积的性质、成因和古气候重要性。该研究将通过支持为德克萨斯州东部历史上代表性不足的高中生举办为期两天的 GEOCAMP 活动来促进 STEM 多样性。此外，该项目将促进高分辨率社区地球系统模型的进一步发展，以更好地了解古代气候变化。该项目将包括对散装沉积物和石英粒度、石英表面形态、碎屑和高精度锆石U-Pb年代学的现场沉积观测和实验室分析，以研究美国怀俄明州、内布拉斯加州和蒙大拿州的古代黄土矿床。这些代理数据将约束黄土的范围、时间、模式和特征；并确定沉积物来源和沉积物回收机制。这些代理数据将与大气-陆地耦合模型相结合，模拟地形变化、全球气候变冷、冰川作用和海岸线回归引起的区域气候和植被变化，以了解黄土的成因和气候意义。除了获得对黄土沉积物的基本了解外，该项目还将揭示：1）气候变化对始新世-渐新世过渡时期（约 3400 万年前）生物进化的影响； 2）美国西部不同地表隆起模型的有效性； 3) 过渡时期矿物粉尘排放增加对全球降温的潜在积极气候反馈。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力优点和更广泛的影响审查标准进行评估，被认为值得支持。