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.

项目摘要理解对土壤形成的控制：使用U系列不平衡土壤的追踪和约会风化转化是在生物圈，岩石圈，水圈和大气的界面上至关重要的重要自然资源。土壤形成对地表水，海洋和大气的化学反应有深远的影响，但是尚不清楚土壤形成所涉及的速率和过程。 U系的同位素不平衡具有了解土壤形成及其相关的地球化学通量的重要潜力，包括通过土壤形成对CO2的吸收，岩石来源的养分对生态系统的供应以及将溶质和沉积物传递给海洋。该项目研究了土壤形成率如何随着时间而变化，并且是气候的函数。该项目将通过研究以前良好的经历过侵蚀的已知父材料时代的特征良好的土壤谱，从而提供U系列不平衡方法的第一个彻底应用。该项目将通过检查不同母体材料年龄，不同景观位置以及具有相同父母材料的降水梯度的土壤的变化来阐明对土壤形成率和过程的控制。拟议的研究将利用夏威夷先前建立的土壤研究地点。夏威夷是进行这项研究的理想天然实验室，因为它是一个独特的研究梯度的环境，其中只有一个主要的土壤形成因子在恒定的情况下变化而变化。使用详细的物理和化学表征，夏威夷地点已经可用于基于U系列不平衡的风化时间尺度和强度的确定，我将测试假设土壤形成速率与降水和侵蚀速率正相关，并且土壤形成速率降低了土壤寿命高的土壤量的降低。牛津的主持人Gideon Henderson博士拥有使用U系列同位素作为示踪剂的丰富经验，并且在理解土壤形成的基本控制方面具有共同的兴趣。在本研究中收集的数据和想法将对年龄和气候在控制土壤形成和风化率中的作用进行全面研究。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。