蛇纹石化环境非生物成因固态碳质物研究

Researches on the abiogenic condensed carbonaceous matter in the serpentinization environment

超基性岩的蛇纹石化是一种广泛存在的地质过程,在蛇纹石化环境中无机碳可以通过化合形成甲烷等非生物成因有机物,为化能自养生物提供初始能量。近年来,超基性岩及蛇纹岩中发现了固态碳质物(condensed carbonaceous matter,CCM),其中包含无机成因的复杂有机物,可能反映其在生命起源过程中扮演了重要角色。本文介绍了蛇纹石化过程形成的固态碳质物(CCM)的定义、发现过程及赋存特征,并对其形成机制、形成环境的制约因素、无机来源判别等进行了讨论。固态碳质物的形成可能与超基性岩蛇纹石化作用及费托反应有关。它常与铁氧化物或皂石等特定矿物形成共生组合关系,这不仅是其无机化合成因的证据,同时也证明了特定矿物对固态碳质物产生的催化作用。此外,流体中的H_(2)和CO_(2)的比例也会影响固态碳质物的化学组成,纳米孔隙被认为有利于其形成。但是,固态碳质物具体的形成过程及其与甲烷等无机成因简单有机物的相互关系目前尚不清楚,这应是今后的一个重要研究方向。

Serpentinization of ultramafic rocks is a common geological process.In the serpentinization environment,abiogenic organic matters,such as methane,which were generated through reduction of inorganic carbon,would provide necessary energy for chemoautotrophic organisms.In recent years,condensed carbonaceous matter(CCM),which is believed to have contained abiogenic complex organics and have played important role in the origin and evolution processes of life,has been found in ultramafic rocks and serpentine.In this paper,we have introduced the definition,discovery process and occurrence characteristics of the CCM formed in the serpentinization process,and have discussed the formation mechanisms,constraint factors of formation environment,and the discrimination of abiotic sources of the CCM.The formation of CCM is thought to be related to the serpentinization of ultramafic rocks and Fischer-Tropsch reaction.The intergrowth association structure generally formed among the CCM and specific minerals,such as iron oxide or saponite,not only provides evidence for the abiogenic synthesis,but also demonstrates the catalytic effect of specific minerals on the CCM synthesis.In addition,the ratio of H_(2) and CO_(2) in the fluid could have impacted chemical composition of the CCM,and serpentinite nanopores are thought to be beneficial to the CCM formation.However,the specific formation process of the CCM and its interrelationship with abiogenic simple organics,such as methane,are still unknown.They should be further studied in the future as an important research direction.