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Analytical development of sulphur isotope analysis on small (1ug) sulphur samples

小量（1ug）硫样品的硫同位素分析的分析进展

基本信息

批准号：
NE/H011595/1
负责人：
Alexandra Turchyn
金额：
$ 3.29万
依托单位：
University of Cambridge
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2010
资助国家：
英国
起止时间：
2010 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FH011595%2F1
关键词：
Analytical development sulphur isotope analysis

项目摘要

Sulphate is the second most abundant anion in the modern ocean. The main source of sulphate to the ocean is the weathering of sulphur-bearing minerals on the continents, delivering sulphur to the ocean via rivers. The main sink of sulphate from the oceans is the burial of various sulphur bearing minerals such as pyrite and gypsum in various parts of the ocean. Geochemists and paleoceanographers think about sulphate concentrations in the oceans changing over time as a function of changes in these fluxes. For example, should there be more weathering of sulphur from the continents, we would anticipate that sulphate concentrations in the ocean would increase. A common way to track these changes is to measure the ratio of isotopes of sulphur in various sulphur and sulphate minerals. For example, sulphide minerals (such as pyrite) have much more 32S than 34S, meaning the ratio of 34S/32S is very low. This means that if, in Earth history, there was a time when much more pyrite was buried in the ocean, more 32S would be buried in the pyrite, leaving more 34S behind in the ocean - or increasing the ratio of 34S/32S. Thus if we (as paleoceanographers) were measuring the ratio of 34S/32S in sulphate minerals over time and we observed a rapid increase in this ratio, we might hypothesize that there was more pyrite being buried at that point in Earth history. The ability to accurately reconstruct the 34S/32S ratio in sulphate over Earth history is especially important because marine sulphate is very sensitive to changes in the amount of organic carbon that is delivered to the sediments. This is because the largest sink in the sulphur cycle is the burial of sulphide minerals in organic-rich sediments; the source of the sulphide is bacteria, who eat organic-carbon that was originally produced in the surface ocean. The burial of this organic-carbon, in turn, is directly linked to atmospheric oxygen. Thus our reconstructions of the history of atmospheric oxygen rely heavily on our understanding of the 34S/32S ratio in sulphate over Earth history. The two most common minerals on which we measure the 34S/32S ratio in sulphate over Earth history are barium sulphate (barite) and carbonate-associated-sulphate. Barite is not well preserved before 150 million years ago, meaning paleoceanographers have relied heavily on carbonate-associated-sulphate to reconstruct the sulphur cycle over critical earlier intervals in the geologic past. Unfortunately large amounts of carbonate must be dissolved in order to release enough sulphate for isotope analysis. I would like to address this by developing the ability to measure sulphur isotope ratios on much smaller samples. I will do this by establishing a technique that is already used in research groups internationally using equipment we already have at the University of Cambridge. This will allow me to measure sulphur isotope ratios on far smaller samples. This is a proof of concept study in which I will measure sulphur in clusters of individual carbonate shells and compare these analyses with other analyses of sulphur isotope ratios in order to determine that we can measure sulphur isotopes on small samples.

硫酸盐是现代海洋中第二丰富的阴离子。进入海洋的硫酸盐的主要来源是大陆上含硫矿物的风化，通过河流将硫磺输送到海洋。来自海洋的硫酸盐的主要沉淀物是各种含硫矿物的埋藏，如海洋中不同部分的黄铁矿和石膏。地球化学家和古海洋学家认为，海洋中的硫酸盐浓度随着时间的推移而变化，是这些通量变化的函数。例如，如果来自大陆的硫磺有更多的风化，我们预计海洋中的硫酸盐浓度将会增加。跟踪这些变化的一种常见方法是测量各种硫磺和硫酸盐矿物中硫的同位素比率。例如，硫化物矿物(如黄铁矿)的32S比34S多得多，这意味着34S/32S的比值很低。这意味着，如果在地球历史上有一段时间，有更多的黄铁矿被埋在海洋中，那么更多的32S将被埋在黄铁矿中，在海洋中留下更多的34S-或者增加34S/32S的比率。因此，如果我们(作为古海洋学家)测量硫酸盐矿物中34S/32S的比值随着时间的推移，我们观察到这个比值迅速增加，我们可能会假设在地球历史上的那个时间点有更多的黄铁矿被埋藏。准确重建硫酸盐在地球历史上的34S/32S比值的能力特别重要，因为海洋硫酸盐对输送到沉积物中的有机碳量的变化非常敏感。这是因为硫磺循环中最大的沉淀池是埋藏在富含有机物质的沉积物中的硫化物矿物；硫化物的来源是细菌，细菌吞噬了最初在表层海洋中产生的有机碳。这种有机碳的埋藏反过来又与大气中的氧气直接相关。因此，我们对大气氧气历史的重建在很大程度上依赖于我们对硫酸盐中34S/32S比地球历史的理解。在地球历史上，我们用来测量硫酸盐34S/32S比值的两种最常见的矿物是硫酸钡(重晶石)和碳酸盐伴生硫酸盐。重晶石在1.5亿年前没有得到很好的保存，这意味着古海洋学家在过去的地质历史中，严重依赖与碳酸盐伴生的硫酸盐来重建关键早期时期的硫循环。不幸的是，为了释放足够的硫酸盐进行同位素分析，必须溶解大量的碳酸盐。我想通过发展在小得多的样品上测量硫同位素比率的能力来解决这个问题。我将通过建立一种已经在国际研究小组中使用的技术来做到这一点，使用我们在剑桥大学已经拥有的设备。这将使我能够在小得多的样品上测量硫同位素比率。这是一项概念验证研究，我将测量单个碳酸盐壳簇中的硫，并将这些分析与其他硫同位素比率分析进行比较，以确定我们可以在小样本上测量硫同位素。

项目成果

期刊论文数量（10）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

The sulfur cycle below the sulfate-methane transition of marine sediments

DOI：
10.1016/j.gca.2018.07.027
发表时间：
2018-10
期刊：
Geochimica et Cosmochimica Acta
影响因子：
5
作者：
André Pellerin;G. Antler;H. Røy;A. Findlay;F. Beulig;Caroline Scholze;A. Turchyn;B. Jørgensen
通讯作者：
André Pellerin;G. Antler;H. Røy;A. Findlay;F. Beulig;Caroline Scholze;A. Turchyn;B. Jørgensen

Controls on the abiotic exchange between aqueous sulfate and water under laboratory conditions

实验室条件下硫酸盐水溶液和水之间非生物交换的控制