REE patterns for apatites from Proterozoic phosphatic metasediments, Finland

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Authors:Rehtijarvi, P.
Author Affiliations:Primary:
Geol. Surv. Finland, Espoo 02150, Finland
Volume Title:Bulletin of the Geological Society of Finland
Source:Bulletin of the Geological Society of Finland, 55(1), p.77-82. Publisher: Geological Society of Finland, Helsinki, Finland. ISSN: 0367-5211
Publication Date:1983
Note:In English. 15 refs.; illus. incl. 13 anal., table, geol. sketch map
Summary:Several occurrences of uranium- and apatite-bearing metasediments are known in the Precambrian of Finland. The characteristic rock types in the occurrences: metaphosphorite, apatite-bearing carbonate and calc-silicate rocks and apatite-quartz-feldspar gneiss, have been interpreted as metamorphic derivatives of phosphorite and phosphatic sedimentary and pyroclastic rocks. Present modes of occurrence of U include incorporation into fluorapatite and into evenly disseminated uraninite crystals. Thirteen fluorapatite concentrates extracted from these metasediments were analysed for REE, U and Th by NAA. The concentrates averaged (in ppm) La 113, Ce 118, Sm 21, Eu 4.8, Yb 13.7, U 485 and Th 20. The REE distribution patterns of the concentrates are reasonably similar and resemble the REE pattern of apatite from the Tertiary Florida phosphate rock. A marine environment of deposition is suggested for the original phosphatic material. (Author's abstract) [J.M.H.]
Subjects:Apatite; Geochemistry; Metals; Metamorphic rocks; Metasedimentary rocks; Petrology; Phosphates; Precambrian; Proterozoic; Rare earths; Stratigraphy; Trace elements; Upper Precambrian; Europe; Finland; Scandinavia; Western Europe
Coordinates:N594500 N684500 E0314500 E0190000
Abstract Numbers:85M/1605
Record ID:1986017221
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique
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