The role of physical erosion in the weathering of fossil organic carbon: An investigation using the trace element rhenium

物理侵蚀在化石有机碳风化中的作用：使用微量元素铼进行的研究

• 批准号: NE/I001719/1
• 负责人: Robert Hilton
• 金额: $ 9.8万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FI001719%2F1
• 关键词: role; physical; erosion; weathering; fossil

The store of carbon in rock as fossil organic matter contains approximately 20,000 times more carbon than is presently in the atmosphere as the greenhouse gas carbon dioxide. Organic matter has been buried throughout Earth history, countering carbon input from volcanic degassing and playing a role in moderating global climate. However, this fossil organic carbon can be oxidised when rocks are exposed to chemical weathering at the surface and ancient carbon input into the modern environment. It is known that human activities are rapidly increasing the rate of this process by burning fossil fuels. However, the natural rate at which this occurs and how it varies throughout the globe is not well known. Perhaps more importantly, the controls on this carbon transfer from rock to atmosphere are poorly constrained. For example, it is not clear how this carbon source might evolve with changing environmental conditions (e.g. precipitation patterns) on land over the coming decades. This proposal addresses these issues, aiming to better understand how Earth's carbon cycle has functioned in the past, and to predict future changes. This research will quantify the rate of fossil organic carbon weathering in river catchments in the French and Swiss Alps, and the mountains of Taiwan. These rivers have been selected because their physical erosion rate, climatic setting and bedrock geology are all well known and vary between catchments. These are the factors that are thought to be important for fossil organic carbon weathering and the project will test their specific role on this carbon transfer. To achieve these aims, the products of fossil organic carbon weathering will be tracked by determining the geochemical composition of river water and sediment. Specifically, the element rhenium (Re) will be used. Re is bound within organic matter in rocks and so when fossil organic carbon is exposed to weathering Re is dissolved into water, contributing to the dissolved load of a river. The source of Re will be confirmed by comparing its concentration in the river water with other elements released from rocks during chemical weathering. Additional information will be acquired from measuring the solid residue of weathering in soils and river sediments. The Re flux in a river will be calculated using measurements of water discharge and this will be converted into a fossil organic carbon weathering rate using the constraint placed on the source of Re. The fossil organic carbon weathering rate in the studied catchments will be compared to their physical erosion rate, climate (runoff and runoff variability) and bedrock geology. This will provide, for the first time, an empirical link between the rate at which this carbon is transferred from rock and the controlling parameters. As such, it will be possible to extrapolate the findings over a much larger scale, where these parameters are known but the geochemistry of the river water has not been studied. In addition, it will be possible to assess how this carbon source may evolve in response to changes in environmental conditions over the coming decades. It will also allow the balance between fossil organic carbon weathering and organic carbon burial to be more vigorously assessed over longer, geological time periods.

以化石有机物形式储存在岩石中的碳比目前以温室气体二氧化碳形式储存在大气中的碳多约20，000倍。在整个地球历史中，有机物质一直被埋藏，抵消火山脱气的碳输入，并在缓和全球气候方面发挥作用。然而，当岩石暴露于表面的化学风化和古老的碳输入到现代环境中时，这种化石有机碳可以被氧化。众所周知，人类活动正在通过燃烧化石燃料迅速增加这一过程的速率。然而，这种情况发生的自然速度以及它在整个地球仪上的变化情况并不为人所知。也许更重要的是，对这种从岩石到大气的碳转移的控制很难受到约束。例如，目前尚不清楚这种碳源在未来几十年内如何随着陆地上不断变化的环境条件（如降水模式）而演变。该提案解决了这些问题，旨在更好地了解地球的碳循环在过去是如何运作的，并预测未来的变化。这项研究将量化在法国和瑞士阿尔卑斯山的河流集水区，以及台湾山区的化石有机碳风化率。之所以选择这些河流，是因为它们的物理侵蚀率、气候背景和基岩地质都是众所周知的，而且在不同的集水区之间存在差异。这些因素被认为对化石有机碳风化很重要，该项目将测试它们在这种碳转移中的具体作用。为了实现这些目标，将通过确定河水和沉积物的地球化学组成来跟踪化石有机碳风化的产物。具体地，将使用元素Re（Re）。Re被束缚在岩石中的有机质中，因此当化石有机碳暴露于风化时，Re被溶解到水中，有助于河流的溶解负荷。Re的来源将通过比较河水中Re的浓度与岩石在化学风化过程中释放的其他元素来确定。将通过测量土壤和河流沉积物中风化的固体残留物获得更多信息。河流中的Re通量将使用排水量的测量值来计算，并且这将使用对Re源的约束来转换为化石有机碳风化率。研究集水区的化石有机碳风化率将与其物理侵蚀率、气候（径流和径流变化）和基岩地质进行比较。这将第一次提供碳从岩石中转移的速率与控制参数之间的经验联系。因此，将有可能在更大的范围内推断这些发现，其中这些参数是已知的，但河水的地球化学尚未研究。此外，还将有可能评估这种碳源在未来几十年中如何随着环境条件的变化而演变。它还将使化石有机碳风化和有机碳埋藏之间的平衡在更长的地质时期内得到更有力的评估。

项目成果

Geological respiration of a mountain belt revealed by the trace element rhenium

• DOI: 10.1016/j.epsl.2014.06.021
• 发表时间: 2014-10-01
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Hilton, Robert G.;Gaillardet, Jerome;Birck, Jean-Louis
• 通讯作者: Birck, Jean-Louis

Mountain respiration: Rates and patterns of fossil organic carbon oxidation revealed using the trace element rhenium

山地呼吸：使用微量元素铼揭示化石有机碳氧化的速率和模式

• 发表时间: 2013
• 期刊: AGU Fall Meeting Abstracts
• 作者: Hilton R. G.

Orogenesis as a carbon dioxide source or sink? New insights from the organic carbon cycle of Taiwan (Walker Penck Lecture)

造山作用是二氧化碳的源还是汇？

• 发表时间: 2014
• 期刊: European Geophysical Union Meeting 2014
• 作者: Hilton, R. G.

Storm-triggered landslides in the Peruvian Andes and implications for topography, carbon cycles, and biodiversity

• DOI: 10.5194/esurf-4-47-2016
• 发表时间: 2016-01-01
• 期刊: EARTH SURFACE DYNAMICS
• 影响因子: 3.4
• 作者: Clark, K. E.;West, A. J.;Malhi, Y.
• 通讯作者: Malhi, Y.

Climate regulates the erosional carbon export from the terrestrial biosphere

• DOI: 10.1016/j.geomorph.2016.03.028
• 发表时间: 2017-01-15
• 期刊: GEOMORPHOLOGY
• 影响因子: 3.9
• 作者: Hilton, Robert G.