University of Oulu

Mississippi Valley Type ore deposits, the Laisvall Pb-Zn deposit and origin of Pb-Zn-bearing sandstone glacial erratic from the Raahe area

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Author: Mikhaylin, Gleb1
Organizations: 1University of Oulu, Faculty of Technology, Oulu Mining School, Degree Programme in Geosciences
Format: ebook
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 1.2 MB)
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Language: English
Published: Oulu : G. Mikhaylin, 2018
Publish Date: 2018-03-29
Thesis type: Bachelor's thesis


The Geological Survey of Finland collected zinc-, lead- and copper-bearing glacial sandstone boulders in 1970’s and 1980’s south of Raahe, Finland. The origin of these sandstones remains inconclusive. The petrographic analysis shows sphalerite, galena, pyrite and chalcopyrite as the main ore-bearing minerals in the matrix of the sedimentary rocks, associated with quartz, feldspar and calcite. Signs of a carbonate-cemented sediment and metal-rich fluid interaction suggest that mineralization was formed as part of a Mississippi Valley type deposit system. The main hypotheses suggest that the boulders were derived from the Laisvall MVT deposit of Sweden or from an unknown mineralization in the Bothnia Bay. The objective of this study was to make a literature review of the Laisvall deposit and analyze the compositional range of sphalerite in a sample from Raahe and compare it to the chemical characteristics of the Laisvall MVT deposit in Norwegian Caledonides, to determine the origin of Raahe glacial erratic sample. The second objective of the study was to assess the dependency of the color on the iron content of the sphalerite. The study is completed by optical microscopy and electron microprobe analysis (EPMA).

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Copyright information: © Gleb Mikhaylin, 2018. This publication is copyrighted. You may download, display and print it for your own personal use. Commercial use is prohibited.