Rare earth elements (REEs) in vertebrate microremains from the upper Pridoli Ohesaare beds of Saaremaa Island, Estonia: geochemical clues to palaeoenvironment
2015 (English)In: Estonian journal of earth sciences, ISSN 1736-4728, E-ISSN 1736-7557, Vol. 64, no 1, 115-120 p.Article in journal (Refereed) Published
Rare earth element (REE) compositions of Nostolepis sp. scales, spines, plates and tesserae from Ohesaare bone beds were measured by in situ microsampling using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The obtained REE concentrations, normalized to Post-Archean Australian Shale concentrations, were evaluated using basic geochemical calculations and quantifications. The REE compositions were nearly identical across all the morphotypes and histologies of Nostolepis microremains, showing flat REE patterns with slight depletion in heavy REEs. There was no visible enrichment in middle REEs, indicating good geochemical preservation of bioapatite and absence of any pronounced fractionated REE incorporation during later stages of diagenesis. The shale-normalized (La/Yb)(SN) and (La/Sm)(SN) REE ratio compilations indicated adsorption as the dominating REE uptake mechanism across all datapoints. The absence of well-defmed Ce anomaly suggested oxic palaeoseawater conditions, which agrees with the existing interpretations of the Ohesaare sequence as high-energy shoal and regressive open ocean sedimentary environments.
Place, publisher, year, edition, pages
2015. Vol. 64, no 1, 115-120 p.
rare earth elements, palaeoenvironment, Nostolepis, Ohesaare, Silurian
Earth and Related Environmental Sciences Developmental Biology
IdentifiersURN: urn:nbn:se:uu:diva-251827DOI: 10.3176/earth.2015.21ISI: 000351327700022OAI: oai:DiVA.org:uu-251827DiVA: diva2:808178