Authigenic and biogenic minerals in volcanic hot springs of Kamchatka, Russia

• Published in: Geochimica et Cosmochimica Acta
• Main Authors: Zhu, S, Li, Y
• Format: Conference Object
• Language: English
• Published: Pergamon. The Journal's web site is located at http://www.elsevier.com/locate/gca 2010
• Subjects: Earth sciences; Geology; Kamchatka
• Online Access: https://doi.org/10.1016/j.gca.2010.04.037; http://hdl.handle.net/10722/128135

Poster Session - 02d: Precambrian sediments as records of early earth tectonics and ocean-atmosphere-biosphere interactions: no. 35 - Open URL: http://goldschmidt.info/2010/program/programViewfa73.html?session=02d#abstract_2602 This journal supplement is the 2010 Goldschmidt Conference Abstracts Oral Session - 15e: Geological preservation of microorganisms Session chaired by Gordon Southam & Neil Banerjee - Open URL: http://goldschmidt.info/2010/program/programView3399.html?session=15e#abstract_2609 The volcanic hot spring deposits from Kamchatka, Russia were examined by scanning electron microscopy and transmission electron microscopy equipped with energy dispersive spectroscopy. Those hot springs include Burlyashii, Oil pool, Zavarzin, Thermophile and Jen’s vents, which were previously reported for microbial ecology and mineralogy. Opal A spheroids are common in all hot spring sediments with particle size from <20 nm to 50 nm. Euhedral single quartz nanoparticles of 700 nm crystallized from Opal-A can be observed scattered on the surface of anhedral sediments. Anthigenic kaolinite of sharp faces can be observed in all hot springs with Si, Al and O as major compositions and having flaky- and scale-like structures. Iron sulfides are common with a wide spectrum of crystal sizes and morphologies. Small pyritic iron sulfides have octahedral shape with crystal size around 20-80 nm; while pyrite crystals of 200 nm to 500 nm and these >1 μm have cubic structure. The small pyrite crystals are also observed assembled to bigger cubic shapes, showing an ostwald ripening process. There are also spheroid shaped, 1 μm size pyritic aggregates with rough surface which showed a sulfate-reducing bacteria mediated formation of iron-sulfides. Fibrous and tabular gypsum crystals can be observed coexisting with sulfides, indicating local oxidation condition. Euhedral crystals of element sulfur of 30 μm can also be observed. Magnetic minerals are abundant in Jen’s vents, however, no magnetite can be detected, implying ...