Collaborative Research: Stabilized Organic Carbon and Paleoenvironmental Interpretations of Late Quaternary Paleosols

合作研究：稳定有机碳和晚第四纪古土壤的古环境解释

• 批准号: 1226949
• 负责人: Michael Thompson
• 金额: $ 11.74万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-15 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1226949&HistoricalAwards=false
• 关键词: Collaborative; Research; Stabilized; Organic; Carbon

Collaborative Research: Stabilized Organic Carbon and Paleoenvironmental Interpretations of Late Quaternary PaleosolsMichael Thompson, Iowa State University, EAR-1226949Elmer Bettis III, University of Iowa, EAR-1226412Rolfe Mandel, Kansas University, EAR-1226757Jingdong Mao, Old Dominion University, EAR-1226323ABSTRACTPaleosols are widespread archives of paleoenvironmental information. Many Quaternary paleosols are laterally extensive, readily correlated, and suggestive of periods of regional climatic or geomorphic stability. This grant focuses on organic matter (OM) in paleosols. The objectives of this grant are (1) to identify and rank the importance of mechanisms of OM stabilization at the millennial scale, and (2) to significantly refine paleovegetation reconstructions of midcontinent, Late-Quaternary environments. At five sites in Kansas and Nebraska, OM will be studied in buried paleosols as old as 44.6 ka. These paleosols were chosen (1) to characterize paleosol organic matter in the two most widespread surficial materials in the Midcontinent (alluvium and loess), (2) to compare OM that has witnessed primarily aerated conditions (loess soils) with OM that has been subjected to alternating aerated and saturated condition (alluvial soils); (3) to systematically lengthen the periods in which OM has been buried, giving opportunity for early diagenetic changes to occur; and (4) to capitalize on information available from previous studies.This project will improve understanding of which components of soil organic matter are preserved over millennial time scales and why they are preserved. Such understanding will inform reconstructions of Quaternary paleoenvironments and landscapes that are based on OM-hosted proxies. Of particular interest is the hypothesis that a significant component of stable carbon in paleosols consists of charcoal.By evaluating the significance of charcoal in paleosol OM, the roles that fire can play in carbon storage, landscape evolution, and interpretations of paleoclimate can be elucidated. Because some forms of OM bind together mineral particles, paleosol OM components may regulate the ability of sediments to resist erosion, thus impacting landscape evolution. The research will also help to refine geochemical models that predict the amount of carbon that can be effectively sequestered in soils and provide new insights concerning the long-term stability of terrestrial OM and its impact on global carbon cycles.This project will broaden participation of underrepresented groups in earth sciences through collaboration with colleagues and students at Alabama A&M Univ. AAMU students be invited to join the research team during summer sessions as part of ISU's George Washington Carver Summer Internship program and they will be recruited for graduate studies at Iowa State Univ. and Univ. of Iowa.

合作研究：稳定有机碳和晚第四纪古土壤的古环境解释Michael Thompson，爱荷华州立大学，EAR-1226949Elmer Bettis III，爱荷华大学，EAR-1226412Rolfe Mandel，堪萨斯大学，EAR-1226757Jingdong Mao，奥道明大学， EAR-1226323摘要古土壤是广泛存在的古环境信息档案。许多第四纪古土壤横向广泛，易于关联，并暗示区域气候或地貌稳定的时期。这笔赠款的重点是古土壤中的有机物（OM）。 这笔赠款的目标是（1）确定千禧年尺度的 OM 稳定机制的重要性并对其进行排序，以及（2）显着完善大陆中部、晚第四纪环境的古植被重建。在堪萨斯州和内布拉斯加州的五个地点，将在距今 44.6 ka 的埋藏古土壤中研究 OM。选择这些古土壤 (1) 是为了表征中大陆两种最广泛的地表物质（冲积土和黄土）中的古土壤有机质，(2) 是为了将经历过主要通气条件（黄土）的 OM 与经历过曝气条件的 OM 进行比较交替通气和饱和条件（冲积土）； （3）系统地延长OM埋藏期，为早期成岩变化的发生提供机会； （4）利用以前研究中获得的信息。该项目将增进对土壤有机质的哪些成分在千年时间尺度上得以保存以及它们为何被保存的理解。这种理解将为基于 OM 托管代理的第四纪古环境和景观重建提供信息。特别令人感兴趣的是这样的假设：古土壤中稳定碳的重要组成部分是木炭。通过评估古土壤 OM 中木炭的重要性，可以阐明火在碳储存、景观演化和古气候解释中发挥的作用。由于某些形式的 OM 将矿物颗粒结合在一起，古土壤中的 OM 成分可能会调节沉积物抵抗侵蚀的能力，从而影响景观演化。该研究还将有助于完善地球化学模型，预测土壤中可有效封存的碳量，并提供有关陆地有机质长期稳定性及其对全球碳循环影响的新见解。该项目将扩大代表性不足的群体的参与通过与阿拉巴马农工大学的同事和学生合作，建立了地球科学小组。作为 ISU 乔治·华盛顿·卡弗暑期实习计划的一部分，AAMU 的学生被邀请在夏季课程期间加入研究团队，他们将被招募到爱荷华州立大学进行研究生学习。和大学。爱荷华州。