Testing the interactions between chemical weathering and glacial cycles using novel isotope tracers.

使用新型同位素示踪剂测试化学风化和冰川循环之间的相互作用。

• 批准号: 2705378
• 金额: --
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2705378
• 关键词: Testing; interactions; between; chemical; weathering

Throughout geological time, feedback processes have prevented runaway greenhouse and icehouse states, keeping Earth's climate within habitable limits. The continental weathering of silicate rocks has been proposed to play an important role in such climate stability but is surprisingly poorly quantified. This project seeks to provide new constraints on the operation of weathering as a climate feedback. Laboratory experiments will be used to investigate element release and lead (Pb) isotope systematics during the chemical weathering of silicate rocks over a range of lithologies and grain sizes. These results will then be applied to examine variability in silicate weathering through Quaternary glacial-interglacial cycles. Because the ocean is the ultimate repository for the particulate and dissolved products of continental denudation, ocean sediment cores represent unique archives of past weathering changes.A novel combination of isotope tracers extracted from different fractions of marine sediments will quantify weathering changes in response to past climate perturbations. There is also scope to explore Li isotope records in speleothems as proxies for terrestrial weathering linked to terrestrial ice sheet retreat. This research will be carried out in state-of-the-art geochemistry labs within the LOGIC group at UCL. Expertise will be developed in marine sediment extractions, chemical separations, and analysis of both radiogenic and non-traditional stable isotopes by multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS).

在整个地质时期，反馈过程都阻止了失控的温室和冰屋状态，使地球的气候保持在可居住的范围内。硅酸盐岩石的大陆风化已被提议在这种气候稳定性中发挥重要作用，但令人惊讶地量化了。该项目旨在为风化作为气候反馈提供新的限制。实验室实验将用于研究硅酸盐岩石在一系列岩性和晶粒尺寸的化学风化过程中，在化学风化过程中，研究元素释放和铅（PB）同位素系统。然后，这些结果将应用于检查通过第四纪冰川间冰期循环进行硅酸盐风化的变异性。由于海洋是大陆剥离的颗粒和溶解产物的最终存储库，因此海洋沉积物核代表了过去风化变化的独特档案。还有范围可以探索Speleothems中的Li同位素记录，作为与陆地冰盖撤退相关的地面风化的代理。这项研究将在UCL逻辑组的最新地球化学实验室中进行。通过多组偶联的等离子体质谱法（MC-ICP-MS），将在海洋沉积物提取，化学分离和非传统稳定同位素（MC-ICP-MS）中开发专业知识。