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Understanding controls on soil formation: tracing and dating weathering transformations using U series disequilibria

了解土壤形成的控制：利用 U 系列不平衡追踪和测定风化转变

基本信息

批准号：
NE/E012736/1
负责人：
Julie Pett-Ridge
金额：
$ 33.21万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2007
资助国家：
英国
起止时间：
2007 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FE012736%2F1
关键词：
Understanding controls soil formation tracing

项目摘要

Project summary Understanding controls on soil formation: tracing and dating weathering transformations using U-series disequilibria Soils are critically important natural resources at the interface of the biosphere, lithosphere, hydrosphere, and atmosphere. Soil formation has a profound impact on the chemistry of surface waters, the oceans, and the atmosphere, yet the rates and processes involved in soil formation are not well understood. U series isotope disequilibria has important potential for understanding soil formation and its associated geochemical fluxes, including the uptake of CO2 by soil formation, the supply of rock-derived nutrients to ecosystems, and the delivery of solutes and sediment to the oceans. This project investigates how soil formation rates change over time and as a function of climate. This project will provide the first thorough application of the U series disequilibria approach by examining previously well-characterized soil profiles of known parent material age that have experienced minimal erosion. This project will elucidate controls on soil formation rates and processes by examining variations across soils of different parent material ages, different landscape positions, and across precipitation gradients with identical parent material. The proposed research will take advantage of previously established soil research sites in Hawaii. Hawaii is the ideal natural laboratory to do this research because it is an environment where it is uniquely possible to study gradients where only one of the major soil forming factors varies while the others are held constant. Using detailed physical and chemical characterization already available for the Hawaii sites in combination with determinations of the weathering timescale and intensity based on U series disequilibria, I will test the hypotheses that soil formation rates are positively correlated with precipitation and erosion rate, and that soil formation rates decline by orders of magnitude over the lifetime of a soil. The Oxford host, Dr. Gideon Henderson, has extensive experience employing U series isotopes as tracers, and shares a mutual interest in understanding the fundamental controls on soil formation. Data collected and ideas developed in this study will provide a comprehensive examination of the role of age and climate in controlling soil formation and weathering rates. Better understanding of the controls on soil formation will improve global carbon cycle models and enhance our ability to predict effects of global change.

项目摘要了解土壤形成的控制：利用 U 系不平衡追踪和测定风化转变土壤是生物圈、岩石圈、水圈和大气界面上极其重要的自然资源。土壤形成对地表水、海洋和大气的化学性质有着深远的影响，但土壤形成的速率和过程尚不清楚。 U系列同位素不平衡对于了解土壤形成及其相关的地球化学通量具有重要潜力，包括土壤形成对二氧化碳的吸收、向生态系统供应来自岩石的养分以及向海洋输送溶质和沉积物。该项目研究土壤形成率如何随时间和气候的变化而变化。该项目将通过检查先前已明确描述的已知母质年龄且经历了最小侵蚀的土壤剖面，首次彻底应用 U 系列不平衡方法。该项目将通过检查不同母质年龄、不同景观位置的土壤以及相同母质的降水梯度之间的变化，阐明对土壤形成速率和过程的控制。拟议的研究将利用先前在夏威夷建立的土壤研究地点。夏威夷是进行这项研究的理想自然实验室，因为它是一个独特的环境，可以研究梯度，其中只有一个主要土壤形成因素发生变化，而其他因素保持不变。利用夏威夷遗址已有的详细物理和化学特征，结合基于 U 系列不平衡的风化时间尺度和强度的确定，我将检验以下假设：土壤形成速率与降水和侵蚀速率正相关，并且土壤形成速率在土壤的生命周期内呈数量级下降。牛津大学主持人 Gideon Henderson 博士在使用 U 系列同位素作为示踪剂方面拥有丰富的经验，并且对了解土壤形成的基本控制有着共同的兴趣。本研究收集的数据和提出的想法将全面检验年龄和气候在控制土壤形成和风化速率方面的作用。更好地了解土壤形成的控制将改善全球碳循环模型并增强我们预测全球变化影响的能力。