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| Cárdenas, Paco. |
| Siliceous spicules in demosponges exist in a variety of shapes, some of which look like minute spheres of glass. They are called “sterrasters” when they belong to the Geodiidae family (Tetractinellida order) and “selenasters” when they belong to the Placospongiidae family (Clionaida order). Today, the Geodiidae represent a highly diverse sponge family with more than 340 species, occurring in shallow to deep waters worldwide, except for the Antarctic. The molecular phylogeny of Geodiidae is currently difficult to interpret because we are lacking morphological characters to support most of its clades. To fill this knowledge gap, the surface microornamentations of sterrasters were compared in different genera. Observations with scanning electron microscopy... |
| Tipo: Text |
Palavras-chave: Porifera; Systematics; Geodia; Placospongia; Rhaxella; Microfossils; Sterrasters; Selenasters. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00688/80002/82956.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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