Fig 1.
Map of Eurasia showing the locations of the tin ingots mentioned in the text (green dots), other tin objects in the eastern Mediterranean and the Near East before 1000 BCE (yellow dots) and major and minor tin deposits.
1: Mochlos (Crete), Greece, 2: Uluburun, Turkey, 3: Gelidonya, Turkey, 4: Hishuley Carmel, Israel, 5: Kfar Samir south, Israel, 6: Haifa, Israel, 7: Thermi (Lesbos), Greece, 8: Athens, Greece, 9: Phylakopi (Milos), Greece, 10: Rethymno (Crete), Greece, 11: Knossos (Crete), Greece, 12: Kalydon (Crete), Greece, 13: Ialysos (Rhodos), Greece, 14: Salamis (Cyprus), Turkey, 15: Alaca Höyük, Turkey, 16: Tülintepe, Turkey, 17: Mycenae, Greece, 18: Dendra, Greece, 19: Abydos, Egypt, 20: Gurob, Egypt, 21: Tell Abraq, United Arab Emirates, 22: Tepe Yahya, Iran, 23: Salcombe, United Kingdom, 24: Erme Estuary, United Kingdom, 25: S’Arcu e is Forros, Sardinia, Italy, 26: Cornwall/Devon, United Kingdom, 27: Mourne Mountains, Down County, North Ireland (United Kingdom), 28: Brittany, France, 29: Massif Central, France, 30: North Portugal/Spain, 31: Erzgebirge province with the Bohemian-Saxon Erzgebirge, Vogtland, Fichtelgebirge, Kaiserwald (Slavkovský les), 32: Slovak Ore Mountains, Slovak Republic, 33: Mt. Cer, Serbia, 34: Mt. Bukulja, Serbia, 35: Monte Valerio, Italy, 36: Sardinia, Italy, 37: Kestel, Turkey, 38: Hisarcık, Turkey, 39: Eastern Desert, Egypt, 40: Deh Hosein, Iran, 41: Western Afghanistan (Herat and Farah provinces), 42: Central/north-eastern Afghanistan (Hindu Kush), 43: Karnab/Lapas/Čangali (Zeravšan valley), Uzbekistan, 44: Mušiston/Takfon (Hissar Mountains), Tadzhikistan, 45: Pamir, Tadzhikistan, 46: Kyrgyzstan, 47: Tosham, Bhiwani district, India, 48: Bastar district/Koraput district, India, 49 (not on the map): Kazakhstan. Size of green and yellow symbols on the inset map do not correlate with number of objects as on the main map (map: D. Berger, C. Frank using Natural Earth geo data and QGIS Geographic Information System. QGIS Development Team, 2019. Open Source Geospatial Foundation. http://qgis.org).
Table 1.
Compilation of LBA tin ingots from the eastern Mediterranean and related information.
Fig 2.
Map of part of the main settlement of Mochlos with the find location of the tin ingot in storeroom 1.7 (a). Details of the archaeological context inside the storeroom is shown in (b) and a section in north-south direction in (c) (images: modified and reprinted from [12] under a CC BY license, with permission from the INSTAP Academic Press, original copyright 2007).
Fig 3.
The tin ingot from Mochlos on site (a) and close-up view (b) illustrating its disintegrated condition. The original shape of the ingot could only be reconstructed by the discoloration of the soil (photos: J.S. Soles).
Fig 4.
Metal cargos of the alleged ships that wrecked offshore the Israeli coast.
(a) Tin ingots from Hishuley Carmel, part of them with Cypro-Minoan marks; numbering corresponds to the original sample designation in Table 3. (b) Three out of 30 tin ingots from Haifa with Cypro-Minoan inscriptions with their original label from the literature. Scale applies to all ingots on the figure (photos: E. Galili, Fig 4A modified and reprinted from [26] under a CC BY license, with permission from the International Journal of Nautical Archaeology, original copyright 2013).
Table 2.
Archaeometallurgical studies and kind of analyses that had been carried out on LBA tin ingots in the past.
Table 3.
Tin ingots analysed in the present study and in previous projects.
Fig 5.
Graphite plates used for the reduction of the corroded tin samples (a). Resulting tin beads from the white crust, sample MA-145558a (b) and reduced tin from the heterogeneous core, sample MA-145558b (c) of the Mochlos tin ingot (photographs: D. Berger).
Fig 6.
Microscopic documentation of the corroded ingot sample from Mochlos.
(a) overview images from optical microscopy (bright field illumination on the left and polarised light in the middle) and SEM (backscattered electron image on the right); (b) detail from optical microscopy (polarised light) of the area specified in (a) showing differently coloured corrosion; (c) SEM-BSE image of the same area as in (b) with identified mineralogical phases; (d) and (e)–selected areas of (c) seen with higher magnification in which the phases romarchite (rmc), stannic oxide (cst) and silicon and magnesium containing stannic oxide (cst (Si, Mg)) are specified (images: D. Berger).
Fig 7.
Results of X-ray diffraction analysis carried out on the corroded ingots of Mochlos and Uluburun.
The comparison of the surface and the core of the Mochlos tin reveals a mixture of stannic oxide and romarchite in the interior and almost pure stannic oxide at the surface (a). No reflexes of grey tin are actually observed (most intense peak at 23.701°). The Uluburun ingots (b) additionally contain abhurite or are completely composed of this mineralogical phase (all peaks that are not specified belong to abhurite). No grey tin is present (diagrams: D. Berger; data: H.-P. Meyer, University Heidelberg).
Table 4.
Chemical composition (semi-quantitative) of corrosion products of the Mochlos tin ingot determined with SEM-EDX at various positions of the polished cross-section (data: D. Berger).
Table 5.
Bulk chemical composition of the tin ingots determined with Q-ICP-MS and LA-Q-ICP-MS (for the Mochlos and Uluburun ingots).
Fig 8.
Trace element composition (vs. antimony) of ingots examined in this study compared with presumed MBA and LBA tin ingots and objects from Salcombe, the Erme Estuary, Uluburun and S’Arcu e is Forros, Sardinia.
The vertical dotted lines and the numbers represent the detection limits of the Q-ICP-MS for the respective element, values for Mochlos and Uluburun are often lower due to the use of LA-Q-ICP-MS. The correlation coefficients R in (i) were derived from the two groups from the Salcombe tin ingots and serve for comparative purposes only (MA-175671 not shown in this diagram). Legend applies to all diagrams (diagrams: D. Berger, data: L. Lockhoff; [45; 94; 99]).
Fig 9.
Chemical data of the Hishuley Carmel (blue symbols) and Kfar Samir (red symbols) tin ingots collected in this study.
They are compared with data of the same objects from previous studies of Begemann et al. [62] (a) and Gale [31]/Galili et al. [26] (b). The arrows indicate interchangement of data of the respective samples after the recognition of sample confusion (diagrams: D. Berger).
Fig 10.
Cross-section of tin ingot KW 197 (FG-883208) from the Uluburun shipwreck showing residual tin metal embedded in a matrix of corrosion products (mainly abhurite).
The glossy tin patches were examined with LA-Q-ICP-MS as reported in Table 5 (photo: D. Berger).
Fig 11.
Comparison of lead isotope ratios determined in this study with data from the literature.
(a–b) 208Pb/206Pb. (c–d) 206Pb/204Pb. If not stated in the legend (applies to all diagrams), the data was taken from Begemann et al. [62]. The white circles result from data-exchange of different samples (applies to data of Begemann et al. [62]) due to the recognised confusion in the sample set of Galili et al. [26]. Analytical uncertainties are smaller than the symbols (diagrams: D. Berger; data: B. Höppner; [26; 62]).
Fig 12.
Lead isotope composition of the tin ingots examined in this study.
(a) 206Pb/204Pb vs. 207Pb/204Pb compared with older data from Stos-Gale et al. [16] for the Uluburun objects. The data points of the Israeli ingots exhibit a linear trend which holds chronological information on the formation age of the original tin ores. The specified date of 291 ± 17 Ma was calculated as described in the text. (b) Isorchrons derived from lead isotope data of tin deposits in the Erzgebirge province (black) [121] and Logrosán (grey) [123] (no Pb-Pb data is available for the British tin sources). In (c) the 206Pb/204Pb ratio is plotted against the δ124Sn values. Analytical uncertainties are smaller than the symbols (diagrams: D. Berger; data: B. Höppner, G. Brügmann).
Fig 13.
206Pb/204Pb isotope ratio of the tin ingots vs. the concentration of trace elements determined in this study.
The dotted lines and specified values represent the limit of detection of the Q-ICP-MS, values for Mochlos are often lower due to the use of LA-Q-ICP-MS. Legend applies to all diagrams (diagrams: D. Berger; data: B. Höppner, N. Lockhoff).
Table 6.
Tin isotope composition (δ124Sn, 2SD) and lead isotope ratios of all samples from this study.
Fig 14.
Tin isotope composition (δ124Sn) of the tin ingots examined in this study and comparison with tin ores.
(a) Isotope composition of the ingots without taking the pyrometallurgical fractionation into account. (a–f) Comparison of ingots with ores from the Erzgebirge province (b), the British Isles (c), the Iberian peninsula (d), Brittany, the French Massif Central, Egypt, Sardinia, Mount Bukulja and Monte Valerio (e) and central Asia (f). The horizontal bars represent the variation in the tin and are lowered by the value 0.1 ‰ as pyrometallurgical impact on the right hand-side (indicated by the arrow) to yield the estimated original isotope composition of the ingots (cf. [69]). The colours of the bars correspond to the colours of the symbols used for the tin ingots. The numbering for samples in (a) corresponds to the sequence in Tables 6 and S2. Legend applies to all diagrams (diagrams: D. Berger; data: G. Brügmann, to be published numerically in the PhD thesis of J. Marahrens).
Fig 15.
Tin isotope composition (δ124Sn) of the tin ingots vs. the concentration of trace elements determined in this study.
The dotted lines and specified values represent the limit of detection of the Q-ICP-MS. Legend applies to all diagrams (diagrams: D. Berger; data: G. Brügmann, L. Lockhoff).
Fig 16.
Tin and lead isotope composition of the different shaped ingots from Hishuley Carmel and their relationship with the indium contents.
Note the strong correlation of the lead isotopes and indium (R = 0.74). Legend applies to both diagrams (diagram: D. Berger; data: G. Brügmann, B. Höppner, N. Lockhoff).
Table 7.
Possible tin sources for the tin ingots as inferred from the tin isotope data and after accounting for the lead isotope ratios.