标题： 地球上级地幔中非生物来源碳氢化合物的反应 显示英文标题

标题： Reactions of abiogenic hydrocarbons in Earth's upper mantle

摘要： 地球内部烃类燃料的形成传统上被认为是具有生物成因起源；然而，越来越多的证据表明，一些轻质烃类可能并非源自生物过程，而是无机成因。 人们普遍认为费舍尔-托普希（Fisher-Tropsch-type, FTT）反应——通常指地质学意义上无机碳转化为有机物质的过程——也可能发生在地球内部，但深部环境中的水相条件和缺乏工业催化剂表明，该反应与化学工业中的过程可能截然不同。 在这里，我们进行了广泛的从头算分子动力学（ab initio molecular dynamics, AIMD）模拟（>2.4纳秒），以研究在10-13吉帕斯卡（GPa）压力和1000-1400开尔文（K）温度下干混合物以及水溶液中的FTT合成反应。我们发现，在没有任何催化剂的情况下，通过CO的聚合反应可以无机合成出含C、O、H的大分子烃类相关物种。 超临界水，广泛存在于地球深处，不会阻止有机分子的形成，但会限制产物的大小和碳的还原程度。 我们的研究表明，在地幔流体中存在一条之前未被认识的无机成因的烃类合成途径。 这些含碳流体有可能从深层迁移到较浅的地壳储层，从而参与深部碳循环，影响地表碳预算，并可能成为一种新的能源来源。 显示英文摘要

摘要： The formation of hydrocarbon fuels in Earth's interior has traditionally been considered to have biogenic origins; however, growing evidence suggests that some light hydrocarbons may instead originate abiotically. It is widely expected that the Fisher-Tropsch-type (FTT) process, which typically refers to the conversion of inorganic carbon to organic matter in the geologic convention, may also happen in Earth's interior, but the aqueous conditions and absence of industrial catalysts in deep environments suggest that the FTT process can be very different from that in the chemical industry. Here, we performed extensive ab initio molecular dynamics (AIMD) simulations (> 2.4 ns) to investigate the FTT synthesis in dry mixture and in aqueous solutions at 10-13 GPa and 1000-1400 K. We found that large hydrocarbon-related species containing C, O, and H are abiotically synthesized via the polymerization of CO without any catalyst. Supercritical water, commonly found in deep Earth, does not prevent organic molecule formation but restricts product size and carbon reduction. Our studies reveal a previously unrecognized abiogenic route for hydrocarbon synthesis in mantle geofluids. These carbon-containing fluids could potentially migrate from depth to shallower crustal reservoirs, thereby contributing to the deep carbon cycle, influencing surface carbon budgets, and possibly serving as a new energy source.