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-defined 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.
Bau, M. & Dulski, P. 1996. Distribution of yttrium and rare-earth elements in the Penge and Kuruman iron-formations, Transvaal Supergroup, South Africa. Precambrian Research, 79, 37–55.
http://dx.doi.org/10.1016/0301-9268(95)00087-9
Bernat, M. 1975. Les isotopes de l’uranium et du thorium et les terres rares dans l’environment marin. Cahiers OSTROM, Serie Geologique, 7, 65–83.
Cocks, L. R. M. & Torsvik, T. H. 2005. Baltica from the Late Precambrian to mid Palaeozoic: the gain and loss of a terrane’s identity. Earth Science Reviews, 72, 39–66.
http://dx.doi.org/10.1016/j.earscirev.2005.04.001
Ederfield, H. & Pagett, R. 1986. Rare earth elements in ichthyoliths: variations with redox conditions and depositional environment. Science of the Total Environment, 49, 175–197.
http://dx.doi.org/10.1016/0048-9697(86)90239-1
Enax, J., Prymak, O., Raabe, D. & Epple, M. 2012. Structure, composition, and mechanical properties of shark teeth. Journal of Structural Biology, 178, 290–299.
http://dx.doi.org/10.1016/j.jsb.2012.03.012
Fadel, A., Žigaitė, Ž., Blom, H., Pérez-Huerta, A., Jeffries, T., Märss, T. & Ahlberg, P. E. 2015. Palaeoenvironmental signatures revealed from the rare earth element (REE) compositions of vertebrate microremains of the Vesiku Bone Bed (Homerian, Wenlock), Saaremaa Island, Estonia. Estonian Journal of Earth Sciences, 64, 36–41.
http://dx.doi.org/10.3176/earth.2015.07
Herwartz, D., Tütken, T., Münker, C., Jochum, K. P., Stoll, B. & Sander, P. M. 2011. Rare earth element systematics of fossil bone revealed by LA-ICPMS analysis. Geochimica et Cosmochimica Acta, 75, 82–105.
http://dx.doi.org/10.1016/j.gca.2010.09.036
Herwartz, D., Münker, C., Tütken, T., Hoffmann, J. E., Wittke, A. & Barbier, B. 2013a. Lu-Hf isotope systematics of fossil biogenic apatite and their effects on geochronology. Geochimica et Cosmochimica Acta, 101, 328–343.
http://dx.doi.org/10.1016/j.gca.2012.09.049
Herwartz, D., Münker, C., Tütken, T., Hoffmann, J. E., Wittke, A., Barbier, B., Jochum, K. P. & Sander, P. M. 2013b. Rare earth element systematics of fossil bone revealed by LA-ICPMS analysis. Geochimica et Cosmochimica Acta, 103, 161–183.
http://dx.doi.org/10.1016/j.gca.2012.10.038
Hints, O., Ainsaar, L., Männik, P. & Meidla, T. (eds). 2008. The Seventh Baltic Stratigraphical Conference. Abstracts and Field Guide. Geological Society of Estonia, Tallinn, 46 pp.
Kemp, R. A. & Trueman, C. N. 2003. Rare earth elements in Solnhofen biogenic apatite: geochemical clues to the palaeoenvironment. Sedimentary Geology, 155, 109–127.
http://dx.doi.org/10.1016/S0037-0738(02)00163-X
Kohn, M. J., Schoeninger, M. J. & Barker, W. W. 1999. Altered states: effects of diagenesis on fossil tooth chemistry. Geochimica et Cosmochimica Acta, 63, 2737–2747.
http://dx.doi.org/10.1016/S0016-7037(99)00208-2
Lécuyer, C., Grandjean, P., Barrat, J.-A., Nõlvak, J., Emig, C. C., Paris, F. & Robardet, M. 1998. δ18O and REE contents of phosphatic brachiopods: a comparison between modern and lower Paleozoic populations. Geochimica et Cosmochimica Acta, 62, 2429–2436.
http://dx.doi.org/10.1016/S0016-7037(98)00170-7
Lécuyer, C., Reynard, B. & Grandjean, P. 2004. Rare earth element evolution of Phanerozoic seawater recorded in biogenic apatites. Chemical Geology, 204, 64–102.
http://dx.doi.org/10.1016/j.chemgeo.2003.11.003
Männik, P. 2014. The Silurian System of Estonia. In The 4th Annual Meeting of IGCP 591, The Early to Middle Palaeozoic Revolution, Field Guide (Bauert, H., Hints, O., Meidla, T. & Männik, P., eds), pp. 123–128. Tartu.
Märss, T. & Männik, P. 2013. Revision of Silurian vertebrate biozones and their correlation with the conodont succession. Estonian Journal of Earth Sciences, 62, 181–204.
http://dx.doi.org/10.3176/earth.2013.15
Märss, T. & Nestor, V. 2014. Ohesaare cliff. In The 4th Annual Meeting of IGCP 591, The Early to Middle Palaeozoic Revolution, Field Guide (Bauert, H., Hints, O., Meidla, T. & Männik, P., eds), pp. 200–201. Tartu.
McLennan, S. M. 1989. Rare earth elements in sedimentary rocks: influence of provenance and sedimentary processes. Reviews in Mineralogy and Geochemistry, 21, 169–200.
Nestor, H. 1990. Locality 7 : 4 Ohesaare cliff. In Field Meeting, Estonia 1990, An Excursion Guidebook (Kaljo, D. & Nestor, H., eds), pp. 175–178. Institute of Geology, Estonian Academy of Sciences, Tallinn.
Nestor, H. & Einasto, R. 1997. Ordovician and Silurian carbonate sedimentation basin. In Geology and Mineral Resources of Estonia (Raukas, A. & Teedumäe, A., eds), pp. 192–204. Estonian Academy Publishers, Tallinn.
Ounis, A., Kocsis, L., Chaabani, F. & Pfeifer, H.-R. 2008. Rare earth elements and stable isotope geochemistry (δ13C and δ18O) of phosphorite deposits in the Gafsa Basin, Tunisia. Palaeogeography, Palaeoclimatology, Palaeoecology, 268, 1–18.
http://dx.doi.org/10.1016/j.palaeo.2008.07.005
Pander, C. H. 1856. Monographie der fossilen Fische des silurischen Systems der russisch-baltischen Governments. Akademica Wissenschaft, St. Petersburg, 10, 1–91.
Patrick, D., Martin, J. E., Parris, D. C. & Grandstaff, D. E. 2004. Palaeoenvironmental interpretations of rare earth element signatures in mosasaurs (reptilian) from the upper Cretaceous Pierre Shale, central South Dakota, USA. Palaeogeography, Palaeoclimatology, Palaeoecology, 212, 277–294.
http://dx.doi.org/10.1016/S0031-0182(04)00315-3
Reynard, B., Lécuyer, C. & Grandjean, P. 1999. Crystal-chemical controls on rare-earth element concentrations in fossil biogenic apatites and implications for paleoenvironmental reconstructions. Chemical Geology, 155, 233–241.
http://dx.doi.org/10.1016/S0009-2541(98)00169-7
Sire, L.-Y., Donoghue, P. C. J. & Vickaryous, M. K. 2009. Origin and evolution of the integumentary skeleton in non-tetrapod vertebrates. Journal of Anatomy, 214, 409–440.
http://dx.doi.org/10.1111/j.1469-7580.2009.01046.x
Suarez, C. A., Macpherson, G. L., Gonzalez, L. A. & Grandstaff, D. E. 2010. Heterogeneous rare earth element (REE) patterns and concentrations in a fossil bone: implications for the use of REE in vertebrate taphonomy and fossilization history. Geochimica et Cosmochimica Acta, 74, 2970–2988.
http://dx.doi.org/10.1016/j.gca.2010.02.023
Trotter, J. A. & Eggins, S. M. 2006. Chemical systematic of conodont apatite determined by laser ablation. Chemical Geology, 233, 196–216.
http://dx.doi.org/10.1016/j.chemgeo.2006.03.004
Trueman, C. N. 1999. Rare earth element geochemistry and taphonomy of terrestrial vertebrate assemblages. PALAIOS, 14, 555–568.
http://dx.doi.org/10.2307/3515313
Trueman, C. N. & Palmer, M. R. 1997. Diagenetic origin of REE in vertebrate apatite: a reconsideration of Samoilov and Benjamini, 1996. PALAIOS, 12, 495–497.
http://dx.doi.org/10.2307/3515387
Trueman, C. N. & Tuross, N. 2002. Trace elements in recent and fossil bone apatite. In Phosphates: Geochemical, Geobiological, and Materials Importance (Kohn, M. L., Rakovan, J. & Hughes, J. M., eds), Reviews in Mineralogy and Geochemistry, 48, 489–522.
Trueman, C. N., Kocsis, L., Palmer, M. R. & Dewdney, C. 2011. Fractionation of rare earth elements within bone mineral: a natural cation exchange system. Palaeogeography, Palaeoclimatology, Palaeoecology, 310, 124–132.
http://dx.doi.org/10.1016/j.palaeo.2011.01.002
Tütken, T., Vennemann, T. W. & Pfretzschner, H.-U. 2008. Early diagenesis of bone and tooth apatite in fluvial and marine settings: constraints from combined oxygen isotope, nitrogen and REE analysis. Palaeogeography, Palaeoclimatology, Palaeoecology, 266, 254–268.
http://dx.doi.org/10.1016/j.palaeo.2008.03.037
Valiukevičius, J. & Burrow, C. 2005. Diversity of tissues in acanthodians with Nostolepis-type histological structure. Acta Palaeontologica Polonica, 50, 635–649.
Vinn, O. 2014. Cruziana traces from the Late Silurian (Pridoli) carbonate shelf of Saaremaa, Estonia. Estonian Journal of Earth Sciences, 63, 71–75.
http://dx.doi.org/10.3176/earth.2014.06
Vinn, O. & Wilson, M. A. 2013. An event bed with abundant Skolithos burrows from the late Pridoli (Silurian) of Saaremaa (Estonia). Carnets de Geologie [Notebooks on Geology], Letter 02, 83–87.
Wright, J., Seymour, R. S. & Shaw, H. F. 1984. REE and Nd isotopes in conodont apatite: variations with geological age and depositional environment. In Conodont Biofacies and Provincialism (Clarck, D. L., ed.), Geological Society of America Special Paper, 196, 325–340.
http://dx.doi.org/10.1130/SPE196-p325
Wright, J., Schrader, H. & Holster, W. T. 1987. Paleoredox variations in ancient oceans recorded by rare earth elements in fossil apatite. Geochimica et Cosmochimica Acta, 51, 631–644.
http://dx.doi.org/10.1016/0016-7037(87)90075-5
http://dx.doi.org/10.1080/08912963.2013.766184