Formation and Preservation of Microbial Palisade Fabric in Silica Deposits from El Tatio, Chile

• DOI: 10.1089/ast.2019.2025
• Publication Date: 2019-10-30T14:30:37Z
• Authors: Jian Gong; Kimberly D. Myers; Carolina Munoz-Saez; Martin Homann; Joti Rouillard; Richard Wirth; Anja Schreiber; Mark A. van Zuilen
• Keywords: Geologic Sediments; Nitrogen; Mars; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Cyanobacteria; 01 natural sciences; Hot Springs; [SDU] Sciences of the Universe [physics]; Microscopy, Electron, Transmission; Experimental diagenesis; RNA, Ribosomal, 16S; Biosignature; Chile; Research Articles; 0105 earth and related environmental sciences; Sheathed cyanobacteria; Microscopy, Confocal; 660; 500; Water; Sequence Analysis, DNA; Silicon Dioxide; Carbon; [SDU]Sciences of the Universe [physics]; 13. Climate action; Silica sinter; El Tatio; [SDU.STU] Sciences of the Universe [physics]/Earth Sciences; Microscopy, Electron, Scanning

Palisade fabric is a ubiquitous texture of silica sinter found in low temperature (<40°C) regimes hot spring environments, and it formed when populations filamentous microorganisms act as templates for polymerization. Although known that postdepositional processes such biological degradation dewatering can strongly affect preservation these fabrics, the impact extreme aridity has so far not been studied detail. Here, we report detailed analysis recently silicified palisade fabrics from geyser El Tatio, Chile, tracing progressive within matrix. This complemented by heating experiments natural samples to assess role diagenesis. Sheathed cyanobacteria, identified Leptolyngbya sp., were be incorporated into irregular cycles wetting, evaporation, mineral precipitation. Transmission electron microscopy analyses revealed nanometer-sized particles are filling pore space individual cyanobacterial sheaths, giving rise their structural rigidity sustain framework. Diagenesis further show sheaths filaments preferentially preserved relative trichomes, amount water present an important factor overall during burial. study confirms efficiently generated highly evaporative geothermal field, biosignatures most effectively under dry diagenetic conditions.