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Opaque phase petrology and geochemical modeling as a guide to abiotic organic synthesis in the Mid-Atlantic Ridge 15°N area

不透明相岩石学和地球化学建模作为大西洋中脊北纬 15° 地区非生物有机合成的指南

基本信息

批准号：
16054132
负责人：
Professor Dr. Wolfgang Bach
金额：
--
依托单位：
Fachgebiet Petrologie der Ozeankruste
依托单位国家：
德国
项目类别：
Priority Programmes
财政年份：
2005
资助国家：
德国
起止时间：
2004-12-31 至 2008-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/16054132?language=en
关键词：
Opaque phase petrology geochemical modeling

项目摘要

One of the most intriguing aspects of peridotite-hosted hydrothermal systems is the strongly reduced nature of the vent fluids, due to the production of hydrogen by hydrolysis on ferrous iron in the ultramafic host rock. The levels of dissolved hydrogen in these systems are so high that reduced dissolved carbon species are more stable that dissolved inorganic carbon. While it is uncertain to what extent organic synthesis takes place in hydrothermal systems, it has potentially important ramifications for carbon flow and carbon and energy sources for microbial ecosystems within modern and ancient hydrothermal systems. Here, I propose to determine the mineralogical inventory of oxide/sulfide/native metals phases in serpentinites from the Mid-Atlantic Ridge 15ºN area by magnetic and electron microprobe techniques. These phases are not only indicative of temperature and redox conditions during serpentinization, they are also important surface catalysts for organic synthesis reactions. Samples include serpentinites from the Logatchev hydrothermal field and from Ocean Drilling Program (ODP) Leg 209. Electron microprobe and transmission electron microscope analyses are employed to characterize the composition and intergrowth of sulfides, oxides, metal alloys as well as serpentine-brucite phases. Phase petrology and geochemical modelling will be employed to estimate temperature, fluid flux, pH, and redox conditions during serpentinization. These constraints are used in a companion project to calculate the chemical affinities of organic synthesis reactions under the prevailing conditions of water-ultramafic rock interaction.

橄榄岩热液系统最有趣的一个方面是喷口流体的强烈还原性质，这是由于超镁质寄主岩石中的亚铁水解产生氢。这些系统中溶解氢的含量如此之高，以至于还原的溶解碳比溶解的无机碳更稳定。虽然有机合成在热液系统中发生的程度尚不确定，但它对现代和古代热液系统中微生物生态系统的碳流和碳和能量来源具有潜在的重要影响。在这里，我建议用磁性和电子探针技术确定大西洋中脊15ºN地区蛇纹岩中氧化/硫化物/天然金属相的矿物学清单。这些相不仅是蛇纹石化过程中温度和氧化还原条件的指示物，也是有机合成反应的重要表面催化剂。样品包括来自Logatchev热液区和Ocean Drilling Program (ODP) Leg 209的蛇纹岩。利用电子探针和透射电镜分析了硫化物、氧化物、金属合金以及蛇纹石-水镁石相的组成和共生特征。相岩石学和地球化学模拟将用于估算蛇纹岩化过程中的温度、流体通量、pH和氧化还原条件。这些约束在一个配套项目中用于计算在水-超镁铁性岩石相互作用的普遍条件下有机合成反应的化学亲和性。