摘要
最近的实验研究指出微生物在硅化作用中扮演被动的角色。构成细胞外表面的有机功能团只是充当聚合或胶质硅在吸附过程中的异质生长成核点、而且由于不同微生物具有不同的细胞超微结构化学,硅化作用的种属特性模式出现了。除了它们的模板的作用,它们似乎并没有加快硅化作用的动力学过程,顶多它们对硅化作用的量只有些微的贡献。相反地,硅化作用源于超饱和热液流在温泉表面流出时发生的聚合。然而,微生物的确在温泉喷口周围形成硅质泉华(sinters)的构造方面施加了影响。不同的微生物有不同的生长模式,因而影响纹层作用(lamination)的风格,即影响泉华的原生孔隙度和后期成岩胶结的分布。
Recent experimental studies indicate that microorganisms play a passive role in silicification. The organic functional groups that comprise the outer cell surfaces simply serve as heterogeneous nucleation sites for the adsorption of polymeric and/or colloidal silica,and because different microorganisms have different cell ultrastructural chemistry,species-specific patterns of silicification arise.Despite their templating role,they do not appear to increase the kinetics of silicification,and at tne very most,they contribute only marginally to the magnitude of silicification.Instead,silicification is due to the polymerization of silica-supersaturated hydrothermal fluids upon discharge at the surface ot the hot spring.Microorganisms do, however,impart an influence on the fabric of the siliceous sinters that form around hot spring vents.Different microorganisms have different growth patterns,that in turn,affect the style of laminations,the primary porosity of the sinter and the distribution of later-stage diagenetic cementation.
