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

合作研究：稳定的有机碳和晚第四纪古土壤的古环境解释爱荷华州立大学的Michael Thompson，EAR-1226949 Elmer Bettis III，爱荷华大学，EAR-1226412Rolfe Mandel，堪萨斯大学，EAR-1226757京东毛，Old Dominion大学，EAR-1226323ABSTRACT古土壤是广泛的古环境信息档案。许多第四纪古土壤横向分布广泛，很容易对比，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)确定千年尺度上有机质稳定机制的重要性并对其进行评级，(2)显著改进中大陆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，将在埋在地下的古土壤中研究OM，最古老的年代为44.6 ka。选择这些古土壤(1)来表征中大陆两种分布最广泛的地表物质(冲积层和黄土)中的古土壤有机质；(2)比较主要充气条件(黄土)的有机质和经历了充气和饱和交替条件(冲积土)的有机质；(3)系统地延长有机质的埋藏时间，为早期成岩变化提供机会；(4)利用以前研究中获得的信息。这一项目将提高对土壤有机质的哪些成分在千年尺度上被保存以及它们为什么被保存的理解。这样的认识将有助于重建基于OM托管的代理的第四纪古环境和景观。尤其令人感兴趣的假设是，古土壤中稳定碳的一个重要组成部分是木炭。通过评估木炭在古土壤OM中的重要性，可以阐明火在碳储存、景观演变和古气候解释中所起的作用。由于某些形式的有机质结合在一起的矿物颗粒，古土壤有机质组分可能调节沉积物抵抗侵蚀的能力，从而影响景观演变。这项研究还将有助于改进预测土壤中可有效封存的碳量的地球化学模型，并为陆地有机质的长期稳定性及其对全球碳循环的影响提供新的见解。该项目将通过与阿拉巴马农工大学的同事和学生合作，扩大未被充分代表的群体在地球科学领域的参与。作为ISU乔治·华盛顿·卡弗暑期实习计划的一部分，AAMU的学生将被邀请在暑期课程期间加入研究团队，他们将被招募到爱荷华州立大学攻读研究生课程。和大学。来自爱荷华州。

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.