The Vihanti-Pyhäsalmi Area

Laine, E.; Luukas, Jouni; Mäki, Timo; Kousa, Jukka; Ruotsalainen, Aimo; Suppala, I.; Imana, Marcello; Heinonen, Suvi; Häkkinen, Tuulia

doi:10.1007/978-3-319-17428-0_6

Cited by 2 publications

(2 citation statements)

References 13 publications

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“…It is unclear how the fracture systems that met during drilling are related to OSZ but the location (Figure 1 ) and lithologies (Figure 2 ) of the drill hole R-2250 fracture zone indicates close resemblance to it. The fracture zone perforated by the drill hole R-2247 could be evidence of an overthrust structure identified from previous seismic surveys (Laine et al, 2015 ). No graphite or carbonate fillings have been found in either of the fracture zones, demonstrative of a carbon-poor environment.…”

Section: Methodsmentioning

confidence: 60%

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Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

et al. 2015

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Pyhäsalmi mine in central Finland provides an excellent opportunity to study microbial and geochemical processes in a deep subsurface crystalline rock environment through near-vertical drill holes that reach to a depth of more than two kilometers below the surface. However, microbial sampling was challenging in this high-pressure environment. Nucleic acid yields obtained were extremely low when compared to the cell counts detected (1.4 × 104 cells mL−1) in water. The water for nucleic acid analysis went through high decompression (60–130 bar) during sampling, whereas water samples for detection of cell counts by microscopy could be collected with slow decompression. No clear cells could be identified in water that went through high decompression. The high-pressure decompression may have damaged part of the cells and the nucleic acids escaped through the filter. The microbial diversity was analyzed from two drill holes by pyrosequencing amplicons of the bacterial and archaeal 16S rRNA genes and from the fungal ITS regions from both DNA and RNA fractions. The identified prokaryotic diversity was low, dominated by Firmicute, Beta- and Gammaproteobacteria species that are common in deep subsurface environments. The archaeal diversity consisted mainly of Methanobacteriales. Ascomycota dominated the fungal diversity and fungi were discovered to be active and to produce ribosomes in the deep oligotrophic biosphere. The deep fluids from the Pyhäsalmi mine shared several features with other deep Precambrian continental subsurface environments including saline, Ca-dominated water and stable isotope compositions positioning left from the meteoric water line. The dissolved gas phase was dominated by nitrogen but the gas composition clearly differed from that of atmospheric air. Despite carbon-poor conditions indicated by the lack of carbon-rich fracture fillings and only minor amounts of dissolved carbon detected in formation waters, some methane was found in the drill holes. No dramatic differences in gas compositions were observed between different gas sampling methods tested. For simple characterization of gas composition the most convenient way to collect samples is from free flowing fluid. However, compared to a pressurized method a relative decrease in the least soluble gases may appear.

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Section: Methodsmentioning

confidence: 60%

“…Related tonalitic subvolcanic intrusions are also present in the area. After formation, the Pyhäsalmi deposit was subjected to multiphase deformational history where all the formations were refolded in to an upright position (Laine et al, 2015 ).…”

Section: Methodsmentioning

confidence: 99%

Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

et al. 2015

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loopUI-0.1: indicators to support needs and practices in 3D geological modelling uncertainty quantification

et al. 2022

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Abstract. To support the needs of practitioners regarding 3D geological modelling and uncertainty quantification in the field, in particular from the mining industry, we propose a Python package called loopUI-0.1 that provides a set of local and global indicators to measure uncertainty and features dissimilarities among an ensemble of voxet models. Results are presented of a survey launched among practitioners in the mineral industry, enquiring about their modelling and uncertainty quantification practice and needs. It reveals that practitioners acknowledge the importance of uncertainty quantification even if they do not perform it. A total of four main factors preventing practitioners performing uncertainty quantification were identified: a lack of data uncertainty quantification, (computing) time requirement to generate one model, poor tracking of assumptions and interpretations and relative complexity of uncertainty quantification. The paper reviews and proposes solutions to alleviate these issues. Elements of an answer to these problems are already provided in the special issue hosting this paper and more are expected to come.

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The Vihanti-Pyhäsalmi Area

Cited by 2 publications

References 13 publications

Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

Microbiome composition and geochemical characteristics of deep subsurface high-pressure environment, Pyhäsalmi mine Finland

loopUI-0.1: indicators to support needs and practices in 3D geological modelling uncertainty quantification

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