minerals Article Mineralogical Analysis of the Kestel Mine: An Early Bronze Age Source of Tin Ore in the Taurus Mountains, Turkey Wayne Powell 1,*, Evren Yazgan 2, Michael Johnson 3, K. Aslıhan Yener 4 and Ryan Mathur 5 1 Department of Earth and Environmental Science, Brooklyn College, Brooklyn, NY 11210, USA 2 General Directorate of Mineral Research and Exploration (MTA), Ankara 06530, Turkey; [email protected] 3 Stell Environmental Enterprises, Eagleview Corporate Center, Exton, PA 19341, USA; [email protected] 4 Institute for the Study of the Ancient World (ISAW), New York University, New York, NY 10028, USA; [email protected] 5 Department of Geology, Juniata College, Huntingdon, PA 16652, USA; [email protected] * Correspondence: [email protected] Abstract: Since its discovery in 1987, the Early Bronze Kestel Mine has been a topic of archaeological and geological controversy. The initial interpretation of the extensive marble-hosted galleries as the oldest known tin mine was challenged due to the low tin grade in remaining hematite-quartz veins, and it was suggested that Kestel was more likely mined for gold. Mineralogical analysis of the remaining mineralization was compared to a heavy mineral concentrate extracted from the soil preserved within the mine. The compositionally complex, arsenate-rich mineral assemblage from the mine sediment, contrasts with that of the remaining surface mineralization. Thus, the outcropping veins do not represent the nature of the extracted ore. Only one grain of gold was found in the heavy mineral concentrate, whereas cassiterite composed 1.5% of the sample. Cassiterite occurs in complex assemblages with arsenates, clays, hematite, quartz, and dolomite, bearing resemblance to Citation: Powell, W.; Yazgan, E.; hematite-arsenate tin mineralization that occurs near Kayseri, 60 km to the northeast. These findings Johnson, M.; Yener, K.A.; Mathur, R. indicate that although gold was a trace component of the Kestel ore, cassiterite was the mineral of Mineralogical Analysis of the Kestel interest to the Early Bronze Age miners, and that Kestel represents the earliest evidence thus far for Mine: An Early Bronze Age Source of an emerging pattern of local tin exploitation. Tin Ore in the Taurus Mountains, Turkey. Minerals 2021, 11, 91. https://doi.org/10.3390/ Keywords: geoarchaeology; Bronze Age; cassiterite; arsenates; Turkey; Ni˘gdeMassif min11010091 Received: 30 December 2020 Accepted: 15 January 2021 1. Introduction Published: 19 January 2021 Archaeologists continue to seek to identify the sources of tin ore that supplied the extensive bronze production of the eastern Mediterranean during the Bronze Age. Given Publisher’s Note: MDPI stays neutral that the region lacks major cassiterite deposits, researchers have focused on distant sources with regard to jurisdictional claims in such as the English deposits of Cornwall, the Bohemian ores of the Erzgebirge, and mines published maps and institutional affil- of Central Asia (Tajikistan, Afghanistan, Pakistan) [1–4]. An early second-millennium BC iations. cuneiform tablet excavated from the Central Anatolian trading center of Kültepe describes tin being brought to the city of Assur in northern Iraq from an unknown location in the east, and then transported to Turkey by donkey caravans, consistent with a Central Asian origin of the metal [1]. However, tin bronzes existed 1000 years before the abovementioned texts Copyright: © 2021 by the authors. during the Late Chalcolithic/Early Bronze Age. Others have concluded that a single source Licensee MDPI, Basel, Switzerland. model is untenable, and that smaller tin deposits that would be considered subeconomic by This article is an open access article modern standards likely contributed significantly to the prehistoric metal economy [5–8]. distributed under the terms and The ancient mining site of Kestel in the Central Taurus Mountains of Turkey (35 km conditions of the Creative Commons southeast of the city of Ni˘gde;Figures1 and2) presents the most compelling archaeological Attribution (CC BY) license (https:// evidence for early tin production proximal to the Eastern Mediterranean. Following the creativecommons.org/licenses/by/ General Directorate of Mineral Research and Exploration’s discovery of placer cassiterite 4.0/). Minerals 2021, 11, 91. https://doi.org/10.3390/min11010091 https://www.mdpi.com/journal/minerals Minerals 2021, 11, x FOR PEER REVIEW 2 of 17 The ancient mining site of Kestel in the Central Taurus Mountains of Turkey (35 km Minerals 2021, 11, 91southeast of the city of Niğde; Figures 1 and 2) presents the most compelling archaeolog- 2 of 16 ical evidence for early tin production proximal to the Eastern Mediterranean. Following the General Directorate of Mineral Research and Exploration’s discovery of placer cassit- erite in the Kuruçay stream, near the town of Celaller (Figure 1), open pit mines and col- in the Kuruçay stream, near the town of Celaller (Figure1), open pit mines and collapsed 2 lapsed gallery entrancesgallery entrances were discovered were discovered over 2 km over on 2 kmthe2 adjacenton the adjacent hillside hillside[5]. To date, [5]. To date, archae- archaeologists ologistshave documented have documented 1.5 km 1.5of underground km of underground workings workings totaling totaling more morethan than 4500 m3 3 4500 m of galleriesof galleries at the atKestel the Kestelmine [9] mine. Ore [9 ].was Ore mined was mined predom predominantlyinantly from froma marble a marble host, but host, but also fromalso fromquartzite quartzite and andpegmatite pegmatite dikes dikes [9]. [Open9]. Open pit pitworkings workings were were first first ex- exploited at the ploited at the beginningbeginning of of the the Early Early Bronze Bronze Age, Age, around around 3000 3000 BC BC [10] [10. ].Ceramic Ceramic typology typology and carbon and carbon datingdating of charcoal of charcoal from from within within the themine mine indicate indicate that thatconstruction construction of the of un- the underground derground shaftshaft and andgallery gallery network network was wasbegun begun shortly shortly after, after, and andthat thatmineral mineral processing processing at the site at the site reachedreached its height its height towards towards the end the of end the of Early the Early Bronze Bronze Age Age(ca. 2000 (ca. 2000BC) [10] BC). [10]. Hematite-quartzHematite-quartz veins in the wall veins of the in mine the wall chambers of the were mine found chambers to contain were foundup to to contain up 7900 ppm Sn andto 7900 approximately ppm Sn and 0.5 approximately g/ton gold; both 0.5 g/ton native gold; gold both and native cassiterite gold andwere cassiterite were found in veins foundand soils inveins within and the soils mine within [11]. Pieces the mine of hematite [11]. Pieces vein of materials hematite veinwith materialslow with low tin content weretin discarded content were in the discarded mine and indowns the minelope, andand downslope,Sn-barren hematite and Sn-barren veins re- hematite veins main unmined.remain Furthermore, unmined. Earl Furthermore, and Ö zbal [11] Earl noted and Özbal that [hematite11] noted lumps that hematite that were lumps that were excavated fromexcavated the ore processing from the site ore of processing Göltepe, 2 sitekm ofsoutheast Göltepe, of 2the km Kestel southeast mine, ofcon- the Kestel mine, tained three timescontained the average three Sn times concentration the average of Sn vein concentration material from of Kestel, vein material 647 and from 2080 Kestel, 647 and ppm respectively;2080 powdered ppm respectively; hematitic powdered ore found hematitic in ceramic ore containers found in ceramicat the same containers site at the same were even moresite enriched, were even with more 4464 enriched, ppm tin, with suggesting 4464 ppm that tin, ore suggesting was being that treated ore was to being treated to concentrate tinconcentrate [11]. In addition, tin [11]. over In addition, one ton overof ceramic one ton crucible of ceramic fragments crucible fragmentswere exca- were excavated vated from Göltepefrom [10] Göltepe. Vitrified [10]. Vitrifiedsurfaces on surfaces the inner on thesurfaces inner of surfaces these fragments of these fragments contain contain up to up to 4% tin [9]4%. Based tin [9 on]. Based these onfindings, these findings,the archaeological the archaeological team led teamby K.A. led Yener by K.A. con- Yener concluded cluded that Kestelthat was Kestel worked was worked for its tin for ore. its tin ore. Figure 1. Local geology ofFigure the Kestel 1. Local Mine geology [12]. of the Kestel Mine [12]. 1.1. The Controversy1.1. The Controversy Publication of Publicationthe initial findings of the initialat Kestel findings initiated at Kestel a heated initiated debate a in heated the archaeo- debate in the archaeo- logical literaturelogical as to literaturethe veracity as toof theYener’s veracity conclusions. of Yener’s Muhly conclusions. [13] conducted Muhly [ 13his] conductedown his own petrographic analysispetrographic of a sample analysis taken of a from sample an takenunmined from vein an unminedabove the vein Kestel above mine the Kestel mine entrance. He observedentrance. no He cassiterite observed in no polished cassiterite section, in polished and only section, trace andcassiterite only trace in the cassiterite in the heavy mineral heavyfraction, mineral indicating fraction, a total indicating Sn content a total of only Sn content26ppm. of However, only 26ppm. the sample However, the sample contained severalcontained