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| Lever, Mark A.; Rouxel, Olivier; Alt, Jeffrey C.; Shimizu, Nobumichi; Ono, Shuhei; Coggon, Rosalind M.; Shanks, Wayne C., Iii; Lapham, Laura; Elvert, Marcus; Prieto-mollar, Xavier; Hinrichs, Kai-uwe; Inagaki, Fumio; Teske, Andreas. |
| Sediment-covered basalt on the flanks of mid-ocean ridges constitutes most of Earth's oceanic crust, but the composition and metabolic function of its microbial ecosystem are largely unknown. By drilling into 3.5-million-year-old subseafloor basalt, we demonstrated the presence of methane-and sulfur-cycling microbes on the eastern flank of the Juan de Fuca Ridge. Depth horizons with functional genes indicative of methane-cycling and sulfate-reducing microorganisms are enriched in solid-phase sulfur and total organic carbon, host delta C-13- and delta S-34-isotopic values with a biological imprint, and show clear signs of microbial activity when incubated in the laboratory. Downcore changes in carbon and sulfur cycling show discrete geochemical intervals... |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00176/28767/32146.pdf |
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| Laverne, Christine; Grauby, Olivier; Alt, Jeffrey C.; Bohn, Marcel. |
| Hydroschorlomite, a Ti-, Ca-, Fe-rich andraditic garnet present in the deepest cores of basalts (661-749 mbsf) drilled in Hole 1256D during Ocean Drilling Program (ODP) Leg 206 (equatorial east Pacific), is reported here for the first time in oceanic crust. Detailed petrological and mineralogical studies by optical microscope, electron microprobe, scanning and transmission electron microscope, and micro-Raman spectroscopy are used to characterize this hydrogarnet and its relationships with other minerals. Hydroschorlomite occurs in Hole 1256D as small (5-50 mu m) anhedral or euhedral crystals associated either with celadonite in black halos adjacent to celadonite veins or with brown saponitic phyllosilicate in brown alteration halos adjacent to veins of... |
| Tipo: Text |
Palavras-chave: Mineralogy and petrology : alteration and weathering processes; Mineralogy and petrology : hydrothermal systems; Hydrogarnet; Titanium; Alteration halo; Low temperature alteration; Oceanic basalt. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-2093.pdf |
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