Geological, hydrogeochemical, and microbiological characteristics of the Oil site of the Uzon caldera (Kamchatka)

Abstract

This study used geological, geochemical, and microbiological data to examine the Uzon oils and conditions within the Uzon caldera. The trace-element compositions of crude oils and solutions from boreholes and hydrothermal springs were determined by ICP-MS. The majority of hydrothermal manifestations within the Uzon caldera are controlled by three trends of faults. The major fault zone, trending nearly E–W, is located between Kikhpinych and Taunshits volcanoes. It acts as a magma conduit and hosts numerous oval-shaped hydrothermal vents. The Oil site is situated on the periphery of the hottest area of highest hydrothermal activity within the Eastern thermal field. On the Eh–pH diagram, most solutions of the Uzon caldera define distinct fields and trends which correlate with the stability fields for sulfur and iron. The Oil site is characterized by very wide variations in temperature and Eh–pH parameters of pore solutions. The geochemical signatures of the solutions at this site are broadly similar to those from other areas of the Uzon caldera, but differ in their sulfide ion and sulfate ion concentrations. These differences can be explained by mixing of deep chloride-sodium hydrothermal solutions and solutions produced during surface oxidation of sulfide-containing material. With respect to the average continental crust, the Uzon oil is enriched in S, As, and Hg. The crude oil and solutions have broadly similar concentrations of B, S, Cl, As, Se, Br, Cd, I, Hg, and Pb and highly variable concentrations of Ti, V, Cr, Co, Ni, Cu, Cd, Nb, and Sn. The community structure of archaeal assemblages in springs and test pits at the Eastern thermal field was analyzed by 16S rRNA library and pyrosequencing methods. It was found that the proportion of archaea in the microbial communities of the Uzon caldera ranges from 2 to over 70% of the total sequences identified. Crenarchaeota were found in large proportions in all samples except one. The majority of the sequences in four samples were affiliated with Euryarchaeota, which comprise methanogenic archaea, extreme halophiles, and some extreme thermophiles. The results of geological, mineralogical-geochemical, microbiological and physicochemical studies of oil seeps in the Uzon caldera reveal distinctive geochemical characteristics of crude oil and the complexity of oil formation.

Main minerals of abnormally high-grade ores of the Tomtor deposit (Arctic Siberia)

“…The sediments of thermal lakes, e.g., in the Uzon-Geyser depression, consist of diatom and clay mud. Although the systems of thermal vents in the present Uzon-Geyser volcanic belt are very different from what is observed in the Tomtor massif both in geology and chemistry (Dobretsov et al, 2015), some analogy is possible. In the microbial communities of the Uzon-Geyser springs, calcium, iron, and manganese phosphates precipitated upon bacterial cells (Lazareva, 2014) at low P contents in the water (to 160 ppm, Fig.…”

Layered Nb-REE ores in the Tomtor Complex (Arctic Siberia): Formation conditions

“…We performed preliminary thermodynamic calculations as in [11,12]. Hydrous Ce, La, and Nd phosphates have similar stability fields in a zone (Fig.…”

“…The possibility for the formation of REE phosphates and Fe-minerals was illustrated with Eh-pH diagrams using the 7.1 HSC software. Thermodynamic calculations were performed using data from the 7.1 HSC database [10], following the principles detailed in previous publications [11,12].…”

Microbiology research at the systems biology and bioinformatics - 2019 (SBB-2019) school

“…The caldera of the Uzon Volcano (Kamchatka Peninsula, Russia) is a region with active hydrothermal activity, which contains outlets of unique natural hydrothermal petroleum [ 8 ] with distinct microbiota. Hydrothermal petroleum is the oil found in natural outlets within active hydrothermal fields [ 8 , 9 ].…”

“…The caldera of the Uzon Volcano (Kamchatka Peninsula, Russia) is a region with active hydrothermal activity, which contains outlets of unique natural hydrothermal petroleum [ 8 ] with distinct microbiota. Hydrothermal petroleum is the oil found in natural outlets within active hydrothermal fields [ 8 , 9 ]. According to carbon 14 C dating, hydrothermal petroleum from various regions of the Earth is modern in geological scale, with the oldest sample being 29,000 years old [ 10 ].…”