In search of the biosphere underneath the Lost City hydrothermal vent field using in-situ sulphur and multiple sulphur isotope signatures

使用原位硫和多种硫同位素特征寻找失落之城热液喷口区下方的生物圈

• 批准号: 320104891
• 负责人: Professorin Dr. Esther Schwarzenbach
• 金额: --
• 依托单位: Institut für Geologische Wissenschaften
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2018-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/320104891?language=en
• 关键词: search; biosphere; underneath; Lost; City

The proposed project plans to use petrography, in-situ sulphur and bulk rock multiple sulphur isotope signatures as tools to identify microbial activity in ultramafic rocks of the Atlantis Massif and to give further insights into the hydrothermal history of this peridotite-hosted hydrothermal system. The Atlantis Massif is an oceanic core complex made up of ultramafic and mafic lithologies. It hosts the Lost City hydrothermal field, which vents high-pH, H2-rich, low-temperature fluids from carbonate-brucite chimneys. These fluids support a unique microbial community within and in the vicinity of the carbonate chimneys. However, the extent of biological activity within the ultramafic subsurface is not well constrained. The recent IODP Expedition 357 to the Atlantis Massif recovered ultramafic and mafic lithologies from the shallow subsurface of the vicinity of the Lost City hydrothermal field using shallow drilling techniques. These samples provide an exceptional opportunity to study the processes that take place within the ultramafic subsurface. In the proposed study bulk rock multiple sulphur isotopes (32S, 33S, 34S, 36S) and in-situ sulphur isotope signatures of individual sulphide grains will be used to identify processes of past microbial activity, such as microbial sulphate reduction, and to measure various abiogenic processes associated with serpentinization. The sulphur isotope data will be combined with mineralogical observations performed in the proposed study (e.g. sulphide mineral assemblages) as well as data collected from other members of the science party of Exp. 357 that provide insight into the fluid chemistry preserved within carbonate and serpentine veins. This will provide better constraints on the extent of microbial activity within the ultramafic rocks and may provide new insights into the conditions that favour microbial activity in the subsurface biosphere.

拟议项目计划利用岩相学、原地硫和大块岩石多种硫同位素特征作为工具，以确定亚特兰蒂斯地块超镁铁质岩石中的微生物活动，并进一步深入了解这一橄榄岩热液系统的热液历史。亚特兰蒂斯地块是一个由超镁铁质和镁铁质岩石组成的海洋核杂岩。它拥有迷城热液场，从碳酸盐水镁石烟囱中喷出高pH值、富含H2的低温流体。这些流体支持碳酸盐烟囱内和附近的独特微生物群落。然而，超镁铁质地下生物活动的程度并没有得到很好的限制。最近对亚特兰蒂斯地块进行的国际大洋钻探项目第357次考察，利用浅钻技术，从迷城热液区附近的浅层地下恢复了超镁铁质和镁铁质岩石。这些样品提供了一个特殊的机会，研究过程中发生的超镁铁质地下。在拟议的研究散装岩石多种硫同位素（32S，33S，34S，36S）和现场硫同位素签名的个别硫化物颗粒将被用来确定过去的微生物活动的过程，如微生物硫酸盐还原，并测量各种非生物过程与蛇纹石化。硫同位素数据将与拟议研究中进行的矿物学观察（例如硫化物矿物组合）以及从Exp科学小组其他成员收集的数据相结合。357提供了对碳酸盐岩和蛇纹岩脉中保存的流体化学性质的深入了解。这将提供更好的限制范围内的超镁铁质岩石的微生物活动，并可能提供新的见解有利于在地下生物圈的微生物活动的条件。

项目成果

Tracking Water‐Rock Interaction at the Atlantis Massif (MAR, 30°N) Using Sulfur Geochemistry

• DOI: 10.1029/2018gc007813
• 发表时间: 2018-11
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: J. Liebmann;E. Schwarzenbach;G. Früh-Green;C. Boschi;S. Rouméjon;H. Strauss;U. Wiechert;T. John