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

合作研究：稳定有机碳与晚第四纪古土壤的古环境解释Michael Thompson，爱荷华州州立大学，E-1226949 Elmer Bettis III，爱荷华州大学，E-1226412 Rolfe Mandel，堪萨斯大学，E-1226757毛靖东，旧自治领大学，E-1226323摘要古土壤是古环境信息的广泛档案。许多第四纪古土壤在横向上是广泛的，容易对比，并暗示区域气候或地貌稳定的时期。该补助金的重点是古土壤中的有机质（OM）。 该补助金的目标是（1）确定和排名的OM稳定机制的重要性在千年尺度，（2）显着改善古植被重建大陆中部，第四纪环境。在堪萨斯和内布拉斯加州的五个地点，有机质将在埋藏的古土壤中进行研究，年龄为44.6万年。这些古土壤被选择来（1）表征中大陆两种最广泛的表层物质中的古土壤有机质（冲积层和黄土），（2）比较OM，见证了主要的曝气条件（黄土）与OM已受到交替通气和饱和条件（3）系统地延长了有机质的埋藏期，为早期成岩作用的发生提供了机会;（4）利用以往研究的信息，提高对土壤有机质中哪些成分在千年时间尺度上被保存下来以及为什么被保存下来的认识。这样的理解将告知基于OM托管代理的第四纪古环境和景观的重建。特别值得注意的是，在古土壤中的稳定碳的一个重要组成部分是木炭的假设，通过评估木炭在古土壤OM的意义，火可以发挥在碳储存，景观演变，古气候的解释可以阐明的作用。由于有机质的某些形式将矿物颗粒结合在一起，古土壤有机质组分可能调节沉积物抵抗侵蚀的能力，从而影响景观演化。该研究还将有助于完善地球化学模型，预测土壤中有效固碳量，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。该项目将通过与亚拉巴马大学的同事和学生合作，扩大地球科学中代表性不足的群体的参与&。作为国际滑联乔治华盛顿卡弗暑期实习计划的一部分，他们将被招募到爱荷华州州立大学和爱荷华州大学进行研究生学习。

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.