Interesting article: Palaeogeography, Palaeoclimatology, Palaeoecology

Early diagenesis of bone and tooth apatite in fluvial and marine settings: Constraints from combined oxygen isotope, nitrogen and REE analysis.                                                                       
T. Tütken(ab), T.W. Vennemann (c),H.-U. Pfretzschner (d)

(a)Institut für Geowissenschaften, Arbeitsbereich für Mineralogie und Geodynamik, Abteilung, Geochemie, Universität Tübingen, Wilhelmstrasse 56, 72074 Tübingen, Germany

(b)Steinmann Institut für Geologie, Mineralogie und Paläontologie, Universität Bonn, Poppelsdorfer Schloss, 53115 Bonn, Germany

(c)Institut de Minéralogie et Géochimie, Université de Lausanne, BFSH 2, 1015 Lausanne, Switzerland

(d)Institut für Geowissenschaften, Arbeitsbereich Biogeologie und Angewandte Paläontologie, Sigwart Strasse 10, Universität Tübingen, 72076 Tübingen, Germany

A B S T R A C T

Fossil bones and teeth of Late Pleistocene terrestrial mammals from Rhine River gravels (RS) and the North Sea (NS), that have been exposed to chemically and isotopically distinct diagenetic fluids (fresh water versus seawater), were investigated to study the effects of early diagenesis on biogenic apatite. Changes in phosphate oxygen isotopic composition (δ18OPO4), nitrogen content (wt.% N) and rare earth element (REE) concentrations were measured along profiles within bones that have not been completely fossilized, and in skeletal tissues (bone, dentine, enamel) with different susceptibilities to diagenetic alteration. Early diagenetic changes of elemental and isotopic compositions of apatite in fossil bone are related to the loss of the stabilizing collagen matrix. The REE concentration is negatively correlated with the nitrogen content, and therefore the amount of collagen provides a sensitive proxy for early diagenetic alteration. REE patterns of RS and NS bones indicate initial fossilization in a fresh water fluid with similar REE compositions. Bones from both settings have nearly collagen-free, REE-, U-, F- and Sr-enriched altered outer rims, while the collagen-bearing bone compacta in the central part often display early diagenetic pyrite void-fillings. However, NS bones exposed to Holocene seawater have outer rim δ18OPO4 values that are 1.1 to 2.6‰ higher compared to the central part of the same bones (δ18OPO4=18.2±0.9‰, n=19). Surprisingly, even the collagenrich bone compacta with low REE contents and apatite crystallinity seems altered, as NS tooth enamel (δ18OPO4=15.0±0.3‰, n=4) has about 3‰ lower δ18OPO4 values, values that are also similar to those of enamel from RS teeth. Therefore, REE concentration, N content and apatite crystallinity are in this case only poor proxies for the alteration of δ18OPO4 values. Seawater exposure of a few years up to 8 kyr can change the δ18OPO4 values of the bone apatite by N3‰. Therefore, bones fossilized in marine settings must be treated with caution for palaeoclimatic reconstructions. However, enamel seems to preserve pristine δ18OPO4 values on this time scale. Using species-specific calibrations for modern mammals, a mean δ18OH2O value can be reconstructed for Late Pleistocene mammalian drinking water of around −9.2±0.5‰, which is similar to that of Late Pleistocene groundwater from central Europe.

Keywords: Bones, Teeth, Oxygen, isotopes, Rare earth elements, Diagenesis, Phosphate

© 2008 Elsevier B.V. All rights reserved. Palaeogeography, Palaeoclimatology, Palaeoecology 266 (2008) 254-268

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Interesting article; Archaeometry (2011)

PROVENANCING FLINT ARTEFACTS WITH ICP–MS USING

REE SIGNATURES AND Pb ISOTOPES AS DISCRIMINANTS:

PRELIMINARY RESULTS OF A CASE STUDY FROM
NORTHERN SWEDENA. OLOFSSON†

Department of Historical, Philosophical and Religious Studies, Umeå University, 901 87 Umeå, Sweden

and I. RODUSHKIN, ALS Scandinavia AB, Aurorum 10, S-977 75, Luleå, Sweden

Archaeological flint artefacts from the late Mesolithic/early Neolithic site of Vuollerim, northern

Sweden, have been geochemically investigated with ICP–SFMS and MC–ICP–MS in

search for the geological/geographical origin of the non-local flint. The Vuollerim flints were

compared with reference samples from Denmark (Cretaceous/Tertiary flint) and Russia (Carboniferous

flint). Elemental concentrations as well as elemental ratios for REEs and isotopic

ratios for Pb and Sr are presented. Significant differences were found between different

geological/geographical contexts. Two of the Vuollerim samples can be ascribed a South

Scandinavian origin. Possibly also eastern flint is present, although the results are not

conclusive in this case.

KEYWORDS:

NORTHERN SWEDEN, ICP–SFMS, MC–ICP–MS, CHERT, FLINT, PROVENANCE

STUDY, REE, Pb ISOTOPES

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