East-central Florida pre-Columbian wood sculpture: Radiocarbon dating, wood identification and strontium isotope studies

Ostapkowicz, Joanna; Wheeler, R. E. M.; Newsom, Lee A.; Brock, Fiona; Bull, Ian D.; Snoeck, Christophe

doi:10.1016/j.jasrep.2017.03.035

Cited by 5 publications

(6 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Two fraction of pitch from Trinidad's Pitch Lake used in this experiments returned 87 Sr/ 86 Sr (±2 SE) values of 0.712275 ± 0.000039 and 0.712251 ± 0.000039 which is distinct from the values of the modern trees sampled from around the lake [0.7107 ± 0.0013 (1 SD; n = 13); Ostapkowicz et al, 2017b]. The pitch 87 Sr/ 86 Sr value is identical to that of T34 and close to that of T81 (0.7130) but very distinct from the 87 Sr/ 86 Sr of T71 (0.7093).…”

Section: Pitch Contamination Experimentsmentioning

confidence: 76%

“…While a large number of studies have focussed on measuring Sr isotopes in archeological human and animal remains (e.g., Price et al, 2006;Bentley, 2013;Laffoon et al, 2014) or charred/carbonized grains (e.g., Benson et al, 2010; though not always successfullysee Styring et al, 2019), as well as on modern plants to establish a biologically available Sr baseline (e.g., Evans et al, 2010;Snoeck et al, 2016Snoeck et al, , 2020, less has been done with archeological wood remains. Exceptions include a study of the well-preserved desiccated structural timbers at Chaco Canyon (English et al, 2001), and of desiccated prehistoric willow and tule textiles in the Great Basin (Benson et al, 2006), as well as some more recent work on pre-Columbian wood sculptures from Florida (Ostapkowicz et al, 2017a) and Trinidad (Ostapkowicz et al, 2017b), waterlogged shipwrecks (Rich et al, 2016;Hajj et al, 2017;Van Ham-Meert et al, 2020), and South American/Lesser Antillean wooden clubs from museum collections (Ostapkowicz et al, 2018). Little targeted research has focused on pretreatments for archeological wood.…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, no pre-treatment was carried out by Hajj et al (2017) prior to analysis of the Ribadeo, a sixteenth century Spanish shipwreck. The few studies that have so far investigated pretreatments for Sr isotope analysis of wood recovered from natural pitch (Ostapkowicz et al, 2017b) or on which consolidants have been applied (Ostapkowicz et al, 2017a(Ostapkowicz et al, , 2018 have used the pre-treatments commonly used in radiocarbon dating to remove carbon contamination (Brock et al, 2010(Brock et al, , 2017(Brock et al, , 2018. These pre-treatments showed that such carbon contamination can be successfully removed adequately using different organic solvents and acid-base-acid (ABA) steps (Brock et al, 2010(Brock et al, , 2017(Brock et al, , 2018Dee et al, 2011;Ostapkowicz et al, 2012Ostapkowicz et al, , 2013.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Testing Various Pre-treatments on Artificially Waterlogged and Pitch-Contaminated Wood for Strontium Isotope Analyses

et al. 2021

Self Cite

View full text Add to dashboard Cite

Strontium isotope ratios (87Sr/86Sr) are commonly used in archeological and forensic studies to assess if humans and fauna are local to the place they were found or not. This approach is largely unexplored for wooden artifacts recovered in archeological contexts, as wood – in the rare instances it does survive – is often poorly preserved. One of the most common ways wood is preserved is through the anoxic conditions found in waterlogged contexts. A more unusual form of preservation is through submergence in natural pitch. These depositional media contribute their own strontium values to the in vivo87Sr/86Sr wood values, which needs to be removed prior to analysis. Here we test several pre-treatment methods to remove potential strontium contamination from wood samples that were artificially immersed in seawater and pitch from Trinidad’s Pitch Lake. Water rinses and acid-leaching tests were carried out with hydrochloric acid and acetic acid to remove exogenous strontium from experimentally waterlogged wood. These tests removed large amounts of strontium from the samples and did not enable the recovery of the endogenous 87Sr/86Sr signal. For samples artificially immersed in pitch, the pre-treatments tested were based on radiocarbon dating procedures and carried out with and without the aqueous-based acid-base-acid (ABA) step. The use of organic solvents alone (methanol and toluene) removed exogenous strontium originating from the pitch. However, the ABA step eliminates large amounts of in vivo strontium from the samples. These tests show that 87Sr/86Sr values of wood are altered by the presence of pitch and water. With adequate pre-treatment using exclusively organic solvents, it may be possible to remove this contamination for samples immersed in pitch. However, the aqueous-based ABA pre-treatment should be avoided. The removal of contamination from waterlogged samples was unsuccessful with the current pre-treatment protocols and more research is needed. More importantly, and unexpectedly, 87Sr/86Sr values may extend outside of the mixing line between the wood’s endogenous strontium and the water. These results indicate the need for extreme caution when attempting to determine the provenance of waterlogged wood.

show abstract

Section: Pitch Contamination Experimentsmentioning

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Testing Various Pre-treatments on Artificially Waterlogged and Pitch-Contaminated Wood for Strontium Isotope Analyses

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Literature review of cleaning methods for isotopic analysis of waterlogged wood (Bird et al, 2014;Von Holstein et al, 2015;Ostapkowicz et al, 2017, Snoeck et al submitted, Brinkkemper et al, 2018Rich et al 2012Rich et al , 2016aMillion et al, 2018;Andreu-Hayles et al, 2019;Büntgen et al, 2020 During immersion in seawater there usually is little bacterial degradation of the wood. Once the timbers are lifted out of the water and come in contact with oxygen, bacterial degradation occurs rapidly.…”

Section: Tablementioning

confidence: 99%

Determining the Sr isotopic composition of waterlogged wood – Cleaning more is not always better

Ham-Meert

Rodler

Waight

et al. 2020

Journal of Archaeological Science

View full text Add to dashboard Cite

Sr isotopes represent a potential means to trace the provenance of archaeological timber. Such tracing allows us to examine the transport, by past people, of wooden objects and of wood and timber as a raw material. However, issues exist with the mobility of Sr and addition of exogenous Sr during waterlogging. This paper presents a systematic assessment of cleaning methods to remove exogeneous Sr from waterlogged wood. Neither a large number of Milli-Q washes, a combination of MQ and Hydrofluoric acid (HF) or alpha-cellulose extraction were able to retrieve the original signature. It was also shown that ashing leads to higher uncertainties due to the smaller amount of Sr available for analysis, this method will only be really useful when large samples are available, is not recommended for small archaeological samples. Our studies also highlight that the distribution of Sr in waterlogged wood is highly heterogeneous.

show abstract

“…Ohlídalová et al 2006) and pyrolysis-GC/MS (e.g. Nishimoto 2011; Ostapkowicz et al 2017). However, these techniques are not always infallible, depending on detection limits and the fact that some conservation treatments are not chemically distinguishable from the samples to which they have been applied (e.g.…”

Section: Introductionmentioning

confidence: 99%

Testing the Effectiveness of Protocols for Removal of Common Conservation Treatments for Radiocarbon Dating

et al. 2017

Self Cite

View full text Add to dashboard Cite

To achieve a reliable radiocarbon (14C) date for an object, any contamination that may be of a different age must be removed prior to dating. Samples that have been conserved with treatments such as adhesives, varnishes or consolidants can pose a particular challenge to 14C dating. At the Oxford Radiocarbon Accelerator Unit (ORAU), common examples of such substances encountered include shellac, the acrylic polymers Paraloid B-67 and B-72, and vinyl acetate-derived polymers (e.g. PVA). Here, a non-carbon-containing absorbent substrate called Chromosorb® was deliberately contaminated with a range of varieties or brands of these conservation treatments, as well as two cellulose nitrate lacquers. A selection of chemical pretreatments was tested for their efficiency at removing them. While the varieties of shellac and Paraloid tested were completely removed with some treatments (water/methanol and acetone/methanol/chloroform sequential washes, respectively), no method was found that was capable of completely removing any of the vinyl acetate-derived materials or the cellulose nitrate lacquers. While Chromosorb is not an exact analog of archaeological wood or bone, for example, this study suggests that it may be possible to remove aged shellac and Paraloid from archaeological specimens with standard organic solvent-acid-base-acid pretreatments, but it may be significantly more difficult to remove vinyl acetate-derived polymers and cellulose nitrate lacquers sufficiently to provide reliable 14C dates. The four categories of conservation treatment studied demonstrate characteristic FTIR spectra, while highlighting subtle chemical and molecular differences between different varieties of shellac, Paraloid and cellulose nitrate lacquers, and significant differences between the vinyl acetate derivatives.

show abstract

East-central Florida pre-Columbian wood sculpture: Radiocarbon dating, wood identification and strontium isotope studies

Abstract: Element) the Université libre de Bruxelles (Belgium) are acknowledged for their help with the strontium isotope analyses by MC-ICP-MS. CS also thanks the BELSPO ColdCase Project for its support.

Cited by 5 publications

References 32 publications

Testing Various Pre-treatments on Artificially Waterlogged and Pitch-Contaminated Wood for Strontium Isotope Analyses

Testing Various Pre-treatments on Artificially Waterlogged and Pitch-Contaminated Wood for Strontium Isotope Analyses

Determining the Sr isotopic composition of waterlogged wood – Cleaning more is not always better

Testing the Effectiveness of Protocols for Removal of Common Conservation Treatments for Radiocarbon Dating

Contact Info

Product

Resources

About