Serpentinization environments are key locations that support microbial communities by the abiogenic formation of reduced species associated with peridotite alteration. Here we studied partially serpentinized peridotites from the Chimaera seeps (Turkey), an active continental serpentinization system that vents highly methane-rich fluids, to investigate the impact of water-rock interaction on the sulfide and metal mineralogy and its implications on supporting microbial communities. Using high-resolution scanning electron microscopy, electron microprobe analysis, and transmission electron microscopy we found diverse pentlandite decomposition features with precipitation of secondary sulfides including millerite, heazlewoodite, as well as Cu-bearing sulfides, native Cu, and awaruite (Ni₃Fe). Awaruite forms dense veinlets to single crystal platelets tens of nanometers in size, which is formed by desulphurization of pentlandite. In addition, the nanometer-sized awaruite platelets are intimately intergrown with serpentine suggesting its growth during peridotite alteration by a dissolution-precipitation process, likely associated with the interaction of methane- and H₂-rich but highly sulfur-undersaturated fluids. Based on sulfur isotope signatures we infer a mantle and mid-ocean ridge origin of the sulfide minerals associated with the first stage of partial serpentinization and awaruite formation. Subsequent and ongoing continental fluid-rock interaction causes significant sulfide decomposition resulting in the formation of porosity and the release of, amongst others, H₂S and Fe. These species may likely provide a source of nutrients for active microbial communities in these comparatively nutrient-starved, low-temperature continental serpentinization environments.

中文翻译：

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大陆蛇形化环境中的硫化物溶解和阿魏石形成及其对维持生命的影响

蛇纹石化环境是通过与橄榄岩蚀变相关的还原物种的非生物形成而支持微生物群落的关键位置。在这里，我们研究了来自Chimaera渗流（土耳其）的部分蛇纹岩化橄榄岩，这是一种活跃的大陆蛇纹石化系统，可排放富含甲烷的流体，以研究水-岩相互作用对硫化物和金属矿物学的影响及其对支持微生物群落的影响。使用高分辨率扫描电子显微镜，电子显微探针分析和透射电子显微镜，我们发现了多种五方陨石分解特征，并伴有次级硫化物的沉淀，包括次生硫，辉石，含铜硫化物，天然铜和微晶石（Ni ₃铁）。Awaruite形成致密的细脉，形成数十纳米大小的单晶血小板，这是由五氧化二磷脱硫形成的。另外，纳米尺寸的淡红岩血小板与蛇纹石紧密地共生，表明其在钙钛矿蚀变过程中通过溶解-沉淀过程而生长，这可能与富含甲烷和H ₂但高度硫不足的流体的相互作用有关。基于硫同位素特征，我们推断出与部分蛇纹石化和海辉石形成的第一阶段有关的硫化物矿物的地幔和中洋脊成因。随后和正在进行的大陆流体-岩石相互作用导致硫化物显着分解，导致形成孔隙并释放出H _2等S和Fe。在这些营养缺乏，低温大陆蛇形化环境中，这些物种可能为活跃的微生物群落提供了营养来源。