Skeletal remains in archaeological strata are often assumed to be of similar ages. Here we show that combined Sr and O isotope analyses can serve as a powerful tool for assessing fish provenance and even for identifying fossil fish teeth in archaeological contexts. For this purpose, we established a reference Sr and O isotope dataset of extant fish teeth from major water bodies in the Southern Levant. Fossil shark teeth were identified within Iron Age cultural layers dating to 8–9th century BCE in the City of David, Jerusalem, although the reason for their presence remains unclear. Their enameloid 87Sr/86Sr and δ18OPO4 values [0.7075 ± 0.0001 (1 SD, n = 7) and 19.6 ± 0.9‰ (1 SD, n = 6), respectively], are both much lower than values typical for modern marine sharks from the Mediterranean Sea [0.7092 and 22.5–24.6‰ (n = 2), respectively]. The sharks’ 87Sr/86Sr are also lower than those of rain- and groundwater as well as the main soil types in central Israel (≥0.7079). This indicates that these fossil sharks incorporated Sr (87Sr/86Sr ≈ 0.7075) from a marine habitat with values typical for Late Cretaceous seawater. This scenario is in line with the low shark enameloid δ18OPO4 values reflecting tooth formation in the warm tropical seawater of the Tethys Ocean. Age estimates using 87Sr/86Sr stratigraphy place these fossil shark teeth at around 80-million-years-old. This was further supported by their taxonomy and the high dentine apatite crystallinity, low organic carbon, high U and Nd contents, characteristics that are typical for fossil specimens, and different from those of archaeological Gilthead seabream (Sparus aurata) teeth from the same cultural layers and another Chalcolithic site (Gilat). Chalcolithic and Iron Age seabream enameloid has seawater-like 87Sr/86Sr of 0.7091 ± 0.0001 (1 SD, n = 6), as expected for modern marine fish. Fossil shark and archaeological Gilthead seabream teeth both preserve original, distinct enameloid 87Sr/86Sr and δ18OPO4 signatures reflecting their different aquatic habitats. Fifty percent of the analysed Gilthead seabream teeth derive from hypersaline seawater, indicating that these seabreams were exported from the hypersaline Bardawil Lagoon in Sinai (Egypt) to the Southern Levant since the Iron Age period and possibly even earlier.
Bibliographical noteFunding Information:
We thank Torsten Vennemann and Michael Maus for performing phosphate oxygen isotope measurements and Hubert Vonhof for running water samples for oxygen isotope analyses and the dentine for carbonate content. We thank B. Stoll and U. Weis for assistance in the LA-MC-ICP-MS laboratory. Modern Mediterranean fish were collected as part of the Israel Oceanographic and Limnological Research deep-sea national monitoring program. We thank Sabine Fiedler and Björn Glasner for total carbon analysis, Sven Brömme for TIC analysis, and Ralf Meffert for the XRD analysis of the dentine samples. Special thanks to Jürgen Kriwet for taxonomic shark tooth identification. Or Bilak is kindly acknowledged for discussing Cretaceous geology of Israel and fossil shark tooth occurrence. Menachem Goren, from the Steinhardt Museum, Tel Aviv University, provided us information regarding the biogeographic distribution of Oreochromis niloticus. We also thank especially Jennifer Leichliter for meticulously proofreading the English. Finally, yet importantly, we want to thank the two reviewers who helped with their constructive comments to significantly improve the manuscript. Especially the reviewer who pointed us to the possibility that the shark teeth from the archaeological layers could be fossil teeth, which was a game changer. It led us to perform additional analysis and, ultimately, to rework the narrative of the manuscript, changing the story from shark exportation from the Nile delta to fossil shark finds in cultural layers. This was a textbook example how a good review should work and we are very appreciative. Funding. This project received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement no. 681450). MW is thankful to the Max Planck Graduate Center for funding.
This project received funding from the European Research Council (ERC) under the European Union’s Horizon 2020
© Copyright © 2020 Tütken, Weber, Zohar, Helmy, Bourgon, Lernau, Jochum and Sisma-Ventura.
- fish provenance
- fossil shark teeth
- oxygen isotopes
- strontium isotopes
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics