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| Gong, Jian; Myers, Kimberly D.; Munoz-saez, Carolina; Homann, Martin; Rouillard, Joti; Wirth, Richard; Schreiber, Anja; Van Zuilen, Mark A.. |
| Palisade fabric is a ubiquitous texture of silica sinter found in low temperature (<40 degrees C) regimes of hot spring environments, and it is formed when populations of filamentous microorganisms act as templates for silica polymerization. Although it is known that postdepositional processes such as biological degradation and dewatering can strongly affect preservation of these fabrics, the impact of extreme aridity has so far not been studied in detail. Here, we report a detailed analysis of recently silicified palisade fabrics from a geyser in El Tatio, Chile, tracing the progressive degradation of microorganisms within the silica matrix. This is complemented by heating experiments of natural sinter samples to assess the role of diagenesis. Sheathed... |
| Tipo: Text |
Palavras-chave: Silica sinter; Biosignature; El Tatio; Sheathed cyanobacteria; Experimental diagenesis; Mars. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00637/74902/76135.pdf |
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| Wilmeth, Dylan T.; Nabhan, Sami; Myers, Kimberly D.; Slagter, Silvina; Lalonde, Stefan; Sansjofre, Pierre; Homann, Martin; Konhauser, Kurt O.; Munoz-saez, Carolina; Van Zuilen, Mark A.. |
| Siliceous sinter deposits from El Tatio, Chile, preserve a wide variety of depositional environments and biosignatures, from high-temperature (~85 °C) vent-proximal facies to distal deposits dominated by silicified microbial mats. Four cores were drilled into an El Tatio sinster mound and associated distal apron to investigate changes in hydrothermal environments over geologic timescales. Sedimentary and geochemical analysis of multiple sinter cores records the initiation and accretion of diverse depositional features still observed today in El Tatio. Facies adjacent to hydrothermal vents are dominated by laminated sinter crusts on the steep margins of a high-temperature pool, with sparse microbial preservation. Outer margins of the same pool contain... |
| Tipo: Text |
Palavras-chave: Siliceous sinter; Hot springs; El Tatio; Microbialites; Microfossils. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00641/75332/75994.pdf |
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