Pyrite and organic matter closely coexist in some hydrothermally-altered gabbroic xenoliths from the Hyblean Plateau, Sicily. The representative sample consists of plagioclase, Fe-oxides, clinopyroxene, pyrite and minor amounts of many other minerals. Plagioclase displays incipient albitization, clinopyroxene is deeply corroded. Pyrite grains are widely replaced by spongy-textured magnetite, which locally hosts Ca-(and Fe-)sulfate micrograins and blebs of condensed organic matter. Whole-rock trace element distribution evidences that incompatible elements, particularly the fluid-mobile Ba, U and Pb, are significantly enriched with respect to N-MORB values. The mineralogical and geochemical characteristics of the sample, and its U-Pb zircon age of 216.9 ± 6.7 MA, conform to the xenolith-based viewpoint that the unexposed Hyblean basement is a relict of the Ionian Tethys lithospheric domain, mostly consisting of abyssal-type serpentinized peridotites with small gabbroic intrusions. Circulating hydrothermal fluids there favored the formation of hydrocarbons trough Fischer-Tropsch-type organic synthesis, giving also rise to sulfidization episodes. Subsequent variations in temperature and redox conditions of the system induced partial de-sulfidization, Fe-oxides precipitation and sulfate-forming reactions, also promoting poly-condensation and aromatization of the already-formed hydrocarbons. Here we show organic matter adhering to a crystal face of a microscopic pyrite grain. Pyrite surfaces, as abiotic analogues of enzymes, can adsorb and concentrate organic molecules, also acting as catalysts for a broad range of proto-biochemical reactions. The present data therefore may support established abiogenesis models suggesting that pyrite surfaces carried out primitive metabolic cycles in suitable environments of the early Earth, such as endolithic recesses in mafic rocks permeated by hydrothermal fluids.

中文翻译：

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黄铁矿和有机化合物共存于侵入性铁镁质Xenoliths（西西里岛Hyblean高原）：对地下生物发生的影响。

黄铁矿和有机质在西西里海底高原的水热改变的辉长岩异岩中共存。代表性样品包括斜长石，铁氧化物，斜柏，黄铁矿和少量其他矿物。斜长石显示初期的阿尔比特化，斜环茂被深腐蚀。硫铁矿晶粒已被海绵状磁铁矿广泛取代，该磁铁矿局部含有硫酸钙（和铁）微粉和冷凝的有机物气泡。整个岩石中痕量元素的分布表明，不相容元素，特别是流动态的Ba，U和Pb，相对于N-MORB值明显富集。样品的矿物学和地球化学特征，其U-Pb锆石年龄为216.9±6.7 MA，符合基于异生物体的观点，即未暴露的Hyblean基底是爱奥尼亚特提斯岩石圈域的遗迹，主要由深渊型蛇纹岩化橄榄岩和少量辉长岩侵入组成。在那里循环水热流体有利于通过费-托型有机合成形成烃，也引起硫化事件。系统温度和氧化还原条件的随后变化引起部分脱硫，Fe氧化物沉淀和形成硫酸盐的反应，也促进了已经形成的烃的缩聚和芳构化。在这里，我们显示出有机物质附着在微观黄铁矿晶粒的晶体表面上。黄铁矿表面，作为酶的非生物类似物，可以吸附和浓缩有机分子，也可作为各种原始生物化学反应的催化剂。因此，本数据可以支持已建立的生物发生模型，表明黄铁矿表面在早期地球的合适环境中进行了原始的代谢循环，例如由热液渗入的铁镁质岩中的内生石质凹陷。