Biosedimentological Processes That Produce Hot Spring Sinter Biofabrics: Examples from the Uzon Caldera, Kamchatka Russia

Abstract

Though the majority of microorganisms in hot spring ecosystems fail to be preserved as bona fide (carbonaceous) microfossils, the presence of microbial biofilms on accretionary surfaces of hot spring sinters can influence the development of sinter fabrics. The extent of biological influence on a primary sinter fabric depends upon the behavior of the microbial community at the time the sinter accretes as well as on the input of sedimentary processes — chemical and physical — that occur during sinter growth. Our ability to recognize the influence of benthic microbial communities on the fabric of a hydrothermal deposit, whether on Earth or, potentially, another rocky planet like Mars, requires an understanding of the interactions between microbial communities, authigenic mineral deposition, and detrital grain accumulation during sinter formation. Examples of hot springs in Uzon Caldera, Kamchatka, Russia, are discussed to illustrate how changes in the relative input of biological, chemical, and physical processes contribute to sinter biofabric formation and preservation. The conclusions drawn from this comparison are relevant to the search for evidence of life in any type of hydrothermal deposit found on a rocky planet.