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，反馈过程阻止了失控的温室和冰库状态，使地球气候保持在适宜居住的范围内。有人提出，硅酸盐岩石的大陆风化在气候稳定性中发挥着重要作用，但令人惊讶的是，其量化却很差。该项目旨在为风化作为气候反馈的运作提供新的限制。实验室实验将用于研究各种岩性和粒度的硅酸盐岩石化学风化过程中的元素释放和铅 (Pb) 同位素系统学。然后，这些结果将用于研究第四纪冰川-间冰期循环中硅酸盐风化的变化。由于海洋是大陆剥蚀颗粒和溶解产物的最终储存库，海洋沉积物岩心代表了过去风化变化的独特档案。从海洋沉积物不同部分提取的同位素示踪剂的新型组合将量化风化变化以应对过去的气候扰动。还可以探索洞穴中的锂同位素记录，作为与陆地冰盖退缩相关的陆地风化的代表。这项研究将在伦敦大学学院逻辑小组内最先进的地球化学实验室中进行。将在海洋沉积物提取、化学分离以及通过多接收器电感耦合等离子体质谱（MC-ICP-MS）分析放射性和非传统稳定同位素方面发展专业知识。