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

在整个地质时期，反馈过程阻止了失控的温室和冰库状态，使地球的气候保持在可居住的范围内。硅酸盐岩石的大陆风化作用被认为在这种气候稳定性中起着重要作用，但令人惊讶的是，量化得很差。该项目旨在提供新的限制风化的操作作为气候反馈。实验室实验将被用来调查元素释放和铅（Pb）同位素系统的化学风化过程中的硅酸盐岩石的岩性和粒度范围。然后，这些结果将被应用于研究通过第四纪冰川间冰期循环硅酸盐风化的变化。由于海洋是大陆剥蚀产物的最终储存地，海洋沉积物岩心代表了过去风化作用的独特档案，一种新的从海洋沉积物不同组分中提取的同位素示踪剂组合将量化风化作用对过去气候扰动的响应。也有范围探索锂同位素记录的洞穴作为代理陆地风化与陆地冰盖退缩。这项研究将在伦敦大学学院LOGIC小组内最先进的地球化学实验室进行。将发展海洋沉积物提取、化学分离以及用多收集器电感耦合等离子体质谱法分析放射性同位素和非传统稳定同位素方面的专门知识。

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).