new data on the exploitation of obsidian in the southern

NEW DATA ON THE EXPLOITATION OF OBSIDIAN IN THESOUTHERN CAUCASUS (ARMENIA, GEORGIA) AND EASTERN

TURKEY, PART 1: SOURCE CHARACTERIZATION*

C. CHATAIGNER

Archéorient, UMR 5133, CNRS/Université Lyon 2, 7 rue Raulin, 69007 Lyon, France

and B. GRATUZE†

IRAMAT CEB, UMR 5060, CNRS/Université d’Orléans, 3 D rue de la Férollerie, 45071 Orléans Cedex 2, France

A large analytical programme involving both obsidian source characterization and obsidianartefact sourcing was initiated recently within the framework of the French archaeologicalmission ‘Caucasus’. The results will be presented in two parts: the first part, this paper, dealswith the presentation and characterization of obsidian outcrops in the southern Caucasus,while the second presents some results obtained from a selection of artefacts originating fromdifferent Armenian sites dated to between the Upper Palaeolithic and the Late Bronze Age. Thesame analytical method, LA–ICP–MS (laser ablation inductively coupled plasma mass spec-trometry), has been used to characterize all the studied samples (both geological and archaeo-logical). This method is more and more widely used to determine the elemental composition ofobsidian artefacts, as it causes minimal damage to the studied objects. We present in this firstpart new geochemical analyses on geological obsidians originating from the southern Cau-casus (Armenia, Georgia) and eastern Turkey. These data enhance our knowledge of theobsidian sources in these regions. A simple methodology, based on the use of three diagrams,is proposed to easily differentiate the deposits and to study the early exploitation of thismaterial in the southern Caucasus.

KEYWORDS: OBSIDIAN GEOCHEMISTRY, LESSER CAUCASUS, ARMENIA, GEORGIA,EASTERN TURKEY, OBSIDIAN OUTCROPS, LA–ICP–MS ANALYSES

INTRODUCTION

The southern Caucasus is a region in which obsidian represents practically the only material usedby prehistoric populations for their tools and weapons. Indeed, obsidian deposits are plentiful inArmenia as well as beyond the periphery of its territory, in southern Georgia, western Azerbaijanand eastern Turkey (Fig. 1).

Analysis of the chemical composition of these sources (Keller et al. 1996; Blackman et al.1998; Poidevin 1998) and of artefacts coming from approximately 70 Transcaucasian archaeo-logical sites dating from the sixth to the first millennia bc (Badalyan et al. 2004) have enabled theestablishment of an initial cartography of the movements of obsidian between the Neolithic andthe Iron Age, and confirmation of the great variability in their distribution in the region.

The villagers obtained their supplies either from a single source or from several sources, andthe nearest deposits were not necessarily the most favoured; the factor of direct linear distance,

*Received 28 May 2012; accepted 12 July 2012†Corresponding author: email [email protected]

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Archaeometry 56, 1 (2014) 25–47 doi: 10.1111/arcm.12006

© 2013 University of Oxford

often considered as a determinant in the choice of outcrops (Renfrew 1984), was thus not soimportant. The areas of diffusion of the obsidian sources also appear to have been highlycontrasting. In certain cases (Chikiani), the material travelled in large quantities over greatdistances and in various directions. In other cases (Hatis), the area of diffusion is limited inquantity, distance and direction. Elsewhere (Geghasar), the obsidian was diffused in a limitedquantity, but over very long distances or, on the contrary (Arteni), in high quantities over a limitedterritory.

SOURCES OF OBSIDIAN AND ANALYTICAL METHOD

The studied corpus

Many sources of obsidian exist across the southern Caucasus. An exhaustive survey has enabledthe collection of samples from all these sources, except for those in western Azerbaijan, and thestudy of the conditions of accessibility to the different primary (flows, domes) and the secondary

Figure 1 The distribution of the obsidian sources in the southern Caucasus and eastern Turkey.

26 C. Chataigner and B. Gratuze

© 2013 University of Oxford, Archaeometry 56, 1 (2014) 25–47

(blocks transported by the rivers) deposits. Fifty-five geological samples, from different sourcesin Georgia and Armenia, as well as 25 samples from sources in eastern Turkey, have beenanalysed by LA–ICP–MS (IRAMAT, CNRS/Université d’Orléans) (Table 1).

LA–ICP–MS analysis Analyses of obsidian objects conducted at the Centre Ernest-Babelon ofthe IRAMAT (Orléans) are carried out using an Element XR mass spectrometer from Ther-mofisher Instrument and a VG UV microprobe ablation device.

Routinely, concentrations of 38 elements are determined in obsidian objects. Among them,we find:• the main major and minor constituents (silicon, sodium, potassium, aluminium and iron),which enable classification of the obsidians according to their different types (calc-alkaline,peralkaline, hyperalkaline, hyperaluminous and metaluminous);• the main hydromagmaphile elements (Rb, Sr, Y, Zr, Nb, Cs, Ba, La, Hf, Ta Th, U and rareearths), which characterize the magma and the volcanic rocks that derive from it (Cauvin et al.1991; Gourgaud 1998).

LA–ICP–MS analysis of obsidian objects operates as follows. The objects are placed in theablation cell together with the reference standard materials and are alternatively sampled by alaser beam, which is generated by an Nd–YAG pulsed laser (maximum energy of 3–4 mJ andat a maximum pulse frequency of 15 Hz) operating at 266 nm (quadrupled frequency). Thediameter of the ablation crater ranges from 60 mm to 100 mm, and its depth is around 250 mm.Classic parameters are 70 s of ablation (20 s for pre-ablation and 50 s for analysis) and a6–8 Hz laser shoot rate. The pre-ablation time of 20 s is set to eliminate the transient part ofthe signal and ensure that surface contamination or corrosion does not affect the results of theanalysis.

An argon gas flow carries the ablated aerosol to the injector inlet of the plasma torch,where the matter is dissociated, atomized and ionized (typical flow rate values range from1.15 l min–1 to 1.35 l min–1, depending on the cell size). The ions are then injected into thevacuum chamber of a high-resolution system, which filters the ions depending upon theirmass-to-charge ratio, and they are then collected by the channel electron multiplier or theFaraday cup.

The measurements are carried out in peak jump acquisition mode, taking four points per peakfor counting and analogue detection modes, and 10 points per peak for Faraday detection.Automatic detection mode is used for most of the elements; only sodium, silicon, aluminium andpotassium are systematically detected with the Faraday detector. Silicon is measured on the 28isotope and is used as an internal standard. With our analytical parameters, the scanning timenecessary to measure the 38 selected isotopes is about 2 s. As most of the encountered isobaricinterferences could be resolved by working on uninterfered isotopes, all the measurements arecarried out in low-resolution mode.

Two different standard reference materials are used to calculate the response coefficient factorKy as defined by Gratuze (1999) and thus to convert data into fully quantitative analyses:• The glass standard reference material (SRM) manufactured by NIST: SRM610. It is a soda–lime–silica glass doped with trace elements in the range of 500 ppm. Certified values areavailable for a very limited number of elements. Concentrations from Pearce, Norman andHollocher (Hollocher and Ruiz 1995; Norman et al. 1996; Pearce et al. 1997) are used for theother elements. SRM610 is used to calculate all the Ky response coefficient factors except formagnesium, potassium and iron, which are present at levels that are too low, and aluminium, thevalue of which is not certain enough.

Obsidian in the Caucasus (Armenia, Georgia) and eastern Turkey, part 1 27


Table 1

Volcanic complexesand obsidianoutcropsGeochemical groups

Numberof

samples

Subgroups Location Numberof

samples

Samplesprovided by

GeorgiaChikiani (Paravani,

Kojun Dag)7 Southern flank 2 Authors

Northern flank 2North-east flow 3

ArmeniaAshotsk (Eni-Ël,

Kechut)3 Aghvorik (= Eni-Ël) village 3 Authors

Tsaghkunyats 8 Tsaghkunyats 1 Damlik 3 AuthorsTtvakar 2

Tsaghkunyats 2 Kamakar 2 AuthorsAïkasar 1

Akhurian River(= Sarikamis

North)

3 Akhurian 1(Sarikamis NW)

Near Shirakavan 1 Authors

Akhurian 2(Sarikamis NE)

Near Shirakavan 2 Authors

Arteni 7 Arteni 1 Satani Dar 1 AuthorsMets Arteni 1

Arteni 2 Pokr Arteni 2 AuthorsAragats flow 1

Arteni 3 Pokr Arteni 1 AuthorsAragats flow 1

Gutansar 7 Dzhraber 3 AuthorsFontan 1Alapars 1Gjumush 1Aivazan 1

Hatis (Atis) 4 Hatis 1 Akunk (south-west) 2 AuthorsKaputan (north-west) 1

Hatis 2 Zerborian (south-east) 1 AuthorsGegham 7 Spitaksar, 3 Authors

Geghasar 4Vardenis 1 Khorapor 1 AuthorsSyunik 8 Syunik 1 Bazenk 2 Authors

Syunik 2 Mets Satanakar 1 AuthorsSyunik 3 Mets Sevkar 3 Authors

Pokr Sevkar 2

Eastern TurkeyTendürek 9 From a flat area on the mountain 9 M. D. GlascockMeydan Dag 4 On the outcrops, south-east of the

summit caldera3 C. Kuzucuoglu

and C. MarroConcentration of blocks, on the

south-east flank of the volcano1

Süphan Dag 9 2 km east of Harmantepe 2 M. D. Glascock5 km east of Harmantepe 43 km north of Mum village 3

SarikamisSouth

3 Sarikamis 1 Along the road from Karakurt to Sarikamis 1 M.-C. CauvinSarikamis region 1

Sarikamis 2 Along the road from Karakurt to Sarikamis 1 M.-C. Cauvin



• Corning glass B. This glass was designed to match the compositions of ancient plant ash glass(Verità et al. 1994; Brill 1999, vol. 2, p. 544; Bronk and Freestone 2001; Vicenzi et al. 2002;Dussubieux et al. 2009). Corning B is mainly used to calculate response coefficient factors forsodium, magnesium, aluminium, potassium, calcium, titanium, manganese, iron, strontium andbarium.The reference values used for these standards are given in the table of results obtained for thedifferent obsidian compositional groups.

Each analysis consists of a blank measurement followed by two ablations located at differentplaces on the object. To improve reproducibility and to correct eventual instrumental drifts orchanges in the ablation efficiency, both standards are systematically analysed at the beginningand at the end of the sequence, and every six or eight samples.

Concentrations are calculated using net average intensity counts rates measured for eachisotope. A simplified version of the internal standard calculation method developed by Gratuze(1999) and used by different authors has been adapted to this analytical protocol.

The following formula is used to calculate concentrations for all elements, assuming that thesum of their contents in weight per cent in obsidian is equal to 100%:

% ,Y O Y Y

Si Y

X X

Si Xm n

I

I K

I

I K= ∗

∗⎛⎝

⎞⎠

∗∗

⎛⎝

⎞⎠∑α α

where IY, IX and ISi are the net intensities counts rates, corrected for isotopic abundance, measuredfor elements Y, X and silicon; aY and aX are the conversion factors from element to oxide forelements Y and X; and KY and KX are the response coefficient factors for elements Y and X,calculated as follows:

KI Conc

I ConcY

Ystd Sistd

Sistd Ystd

=∗[ ]∗[ ]

,

where IYstd and ISistd are the net intensities counts rates, corrected for isotopic abundance,measured for element Y and silicon in the standard material and [Conc]Ystd and [Conc]Sistd are theconcentrations of element Y and Si in the standard material.

The experimental detection limits calculated on the basis of a peak intensity equal to threetimes the standard deviation of the average value of the background intensity range from 0.07%to 0.002% for minor elements and from a few ppb to 10 ppm for others (Table 2). Accuracy andreproducibility are difficult terms to estimate when dealing with archaeological material. Thesefactors could only be estimated by using reference materials, and by measuring the differencebetween certified values and calculated values for the accuracy and the deviation measured on theaverage response coefficient factor K for reproducibility. Accuracy is estimated at 15 relative percent for major and minor elements and 110 relative per cent for trace elements.

RESULTS AND DISCUSSION

Twenty-two main different chemical groups of obsidian were obtained from the 14 volcaniccomplexes and secondary deposits that were studied.

Different methods were used to represent compositional groups of obsidian. Depending on theauthors, principal component analysis, hierarchical cluster analysis, extended rare earth elementspidergrams or simple binary diagrams were used. In this work, we choose to use only



elements or element ratio binary diagrams, as they offer the possibility of rapidly comparing dataobtained from different authors and different methods. The elements Rb, Sr, Y, Zr andNb, which are the most utilized and determined elements (all these elements are determined bythe main laboratories and portable methods such as portable non-destructive X-ray fluorescence)together with Ba (less often determined by portable methods) will be mainly used in ourdiscussion. However, others elements such as rare earths may be also used to differentiate sourcesof close chemical compositions (Khalidi et al. 2010). Part of the data taken into account for thediscussion was obtained between 2005 and 2009 with a PQXS quadrupole mass spectrometer,using the analytical protocol described in previous work (Gratuze 1999). All the samples werere-analysed at least once using the Element XR protocol described above. All these data areplotted on the various diagrams, which explains the large number of points compared to the smallnumber of geological samples. Due to some calibration drifts between the two analytical proto-cols used (e.g., for elements such as zirconium), an artificial separation that tends to split thesource into two close subgroups may appear on some diagrams. These types of subgroupinginduced by an analytical bias will not be considered in the following discussion (e.g., theseparation of Süphan Dag into two subgroups only correlated with the analytical protocol).

In order to simplify the diagrams, the different obsidian flows emitted by the same volcaniccomplex will be represented as a whole on the main diagrams. They will, however, be split intotheir different subgroups in specific diagrams. For some sources, however, our geologicalsamples do not match the entire compositional variability of the different obsidian flows gener-ated by the volcanic complex. Some data published by other authors (Keller and Seifried 1990;Keller et al. 1996; Oddone et al. 1997; Gallet 2001; Delerue 2007) will therefore be used forthese sources.

As shown in the past by Cann and Renfrew (1964), barium and zirconium, and also the Nb/Zrand Y/Zr ratios (Gratuze 1999), together with strontium (Binder et al. 2011) remain the bestparameters to distinguish the main obsidian sources (Figs 2–4). Thus, as shown in Table 3, allthe outcrops studied could be distinguished by using three simple diagrams: barium versuszirconium, yttrium/zirconium versus niobium/zirconium and barium/zirconium versus barium/strontium. If some of the volcanic complexes studied have a homogeneous composition(Gutansar, Khorapor), two or more subgroups could be defined for the other volcanic complexesand secondary deposits.

Table 2 The measured isotope, reference material used for standardization (*, N610 and Corning B; **, onlyCorning B, only N610 is used for other elements) and the range of detection limits achieved for obsidian

characterization with the analytical protocol developed withthe Element XR

Average range of lod values Elements

Below 10 ppb 141Pr, 159Tb, 165Ho, 169Tm, 175Lu, 181Ta, 232Th, 238UBetween 10 and 25 ppb 89Y, 93Nb, 139La, 140Ce, 146Nd, 147Sm, 163Dy, 166Er, 172Yb, 178HfBetween 100 and 500 ppb 85Rb, 88Sr*, 90Zr, 133Cs, 153EuBetween 500 and 1000 ppb 66Zn, 157GdBetween 1 and 10 ppm 7Li, 11B, 47Ti*, 55Mn*, 137Ba*Between 25 and 50 ppm 24Mg**, 45Sc, 57Fe**Between 200 and 700 ppm 23Na*, 27Al**, 39K**, 44Ca*

lod, limit of detection.



Chikiani (= Kojun Dag = Paravani)

In southern Georgia, the Chikiani volcano (in Georgian, ‘the glass that glistens’), which reaches2417 m, rises only ~300 m above the shores of the nearby lake Paravani. Its Turkish name, KojunDagh or ‘Cow Mountain’, adequately suggests the gentleness of the relief (Badalyan et al. 2004).The Chikiani obsidian is spread everywhere over the dome of the volcano and extends in a largeflow to the north-east; this flow belongs to an eruptive phase dated to around 2.8 Ma, the southernpart of the dome being about 400 ka younger (Le Bourdonnec et al. 2012). Obsidian is abundantand easy to access, the only limit to exploitation being the thick snow cover that lasts for morethan 6 months. Moreover, the Khrami River, which receives many obsidian blocks from itstributaries that descend from the Chikiani slopes, carries numerous obsidian pebbles as far as itslower course, where sites of the Neolithic Shulaveri–Shomutepe culture, dated to the sixthmillennium bc, are located (Badalyan et al. 2004).

The quality of the obsidian is excellent—very homogeneous and without inclusions. Severalvarieties are found: uniform black, banded black and red, red–brown, mottled brown and black,mottled yellow and brown, and so on.

The chemical analyses show that the samples taken from the Chikiani dome have an identicaltrace element chemical composition and form a single group characterized by low zirconium andhigh barium contents (Fig. 2). Concentrations of these elements are close to those of the Tsagh-kunyats obsidian. Their Nb/Zr and Y/Zr ratios are similar to those defined for Gutansar and Hatis,and allow the distinction of two close subgroups (Fig. 3). However, this obsidian is completelydifferentiated from the other sources by using the Ba/Zr–Ba/Sr diagram (Fig. 4). As observedby Keller et al. (1996), there is a continuous variation of the Ba and Zr concentrations. Thechronological studies have shown that there were several temporally successive flows between

0

200

400

600

800

1000

0 100 200 300

Zr ppm

Ba p

pm

Arteni

Ashotsk

Hatis

Gegham

Gutansar

Chikiani

Akhurian/Sarikamis North

Araxes/Sarikamis South

Syunik

Tsaghkunyats

Khorapor

Süphan Dag

Tendürek

Meydan Dag

Figure 2 The binary diagram for the Zr–Ba contents of the outcrops studied.



2.8 and 2.3 mya (Komarov et al. 1972; Badalyan et al. 2001; Lebedev et al. 2008) and thesevariations correspond to the progressive evolution of the magma.

Ashotsk (= Eni Ël = Kechut)

The Ashotsk obsidian deposits are located in the south-western foothills of the Djavakhetirange near the villages of Aghvorik (Eni-Ël range) and Sizavet, at about 2000 m a.s.l. Theobsidian outcrops are rare and restricted on the surface, since the eruptions, which are datedfrom 2.6 (Komarov et al. 1972; Dzhrbashyan et al. 2001) to 1.1 mya (Oddone et al. 2000),have been covered by basaltic flows, on which vegetation has developed (Badalyan et al. 2004;Ollivier et al. 2010). The volcanic centres of the eruptions are not yet well defined (Kelleret al. 1996).

The Aghvorik and Sizavet obsidians are uniform black, blackish-brown to grey opaque,banded black and red. This obsidian is sufficiently high in quality for working; however, mostof the raw material is small in size (10–15 cm in diameter on average), which limits itsusefulness.

The outcrops of Aghvorik and Sizavet are located 6–7 km from each another, but all thesamples form a single homogeneous composition group. The Ashotsk obsidian is well separatedfrom all the other groups on the different diagrams. They are characterized by high zirconium andbarium contents and thus very low Nb/Zr and Y/Zr ratios.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.5 1.0 1.5 2.0

Nb/Zr

Y/Z

r

Arteni

Ashotsk

Hatis

Gegham

Gutansar

Chikiani



Syunik

Tsaghkunyats

Khorapor

Süphan Dag

Tendürek

Meydan Dag

Figure 3 The binary diagram of the Nb/Zr–Y/Zr ratios for the outcrops studied.



Tsaghkunyats

The Tsaghkunyats range, which stretches north-east of the Aragats massif, contains severalvolcanoes with obsidian flows, which are the oldest in Armenia, dating back c. 4.5 mya(Oddone et al. 2000; Badalyan et al. 2001). From west to east, one encounters the obsidiandeposits of Damlik (2781 m), Ttvakar, Kamakar, Arkayasar, Aykasar and Dalar (or Dallyar),with blocks of various sizes up to 1 m in diameter. These obsidian flows are relatively easy toaccess, since the slopes are not steep. Moreover, the Kasakh and Marmarik Rivers, whichborder the range, carry numerous obsidian boulders and pebbles that wash down from themountain slopes after heavy rains. Thus, Hankavan, which is sometimes described as an obsid-ian deposit, is in fact the name of a village situated at the northern foot of the chain wherenumerous currents join together to form the Marmarik River. In the Kasakh River, obsidianpebbles were collected by the Neolithic human group living in the Kmlo cave: several artefactshave retained the cortex of the pebbles rolled down by the river (Chataigner and Gratuze2013).

The obsidian is mainly uniform black, sometimes red; banded black and red blocks are alsofound.

The Tsaghkunyats obsidian forms two well-identified compositional groups according to theirbarium and zirconium contents, which are close to those of Chikiani obsidian (Fig. 2). These twogroups are, however, identified and separated from Chikiani obsidian by their Nb/Zr–Y/Zr ratiosas shown in Figure 5. In the first subgroup, we find the obsidian from Damlik and Ttvakar(referred to as Tsaghkunyats 1), and in the second one the obsidian from Kamakar and Aïkasar(referred to as Tsaghkunyats 2).

0

10

20

30

40

50

60

0 2 4 6 8 10 12

Ba/Zr

Ba/S

r

Arteni

Ashotsk

Hatis

Gegham

Gutansar

Chikiani



Syunik

Tsaghkunyats

Khorapor

Süphan Dag

Tendürek

Meydan Dag

Figure 4 The binary diagram of the Ba/Zr–Ba/Sr ratios for the outcrops studied.



Akhurian River (secondary deposit) and Sarikamis (primary deposits)

In the valley of the Akhurian, at the confluence of the Akhurian and Kars Rivers, an alluvial level,containing numerous obsidian pebbles, is visible in the section of the ancient terraces. Thisobsidian, dated to between 4.1 and 3.5 mya (Bigazzi et al. 1998), is of very good quality, but thepebbles are small (less than 10 cm in diameter). It varies in colour, being mainly uniform black,but also red or brown.

According to the geologists, the Akhurian obsidian pebbles were brought by the Kars River.This river rises in the region of Sarikamis, where at least two generations of obsidian, separatedby a time gap of about a million years, are present (Bigazzi et al. 1998; Poidevin 1998). Theearliest episode (between 4.8 and 4.3 Ma) concerns a territory stretching more than 15 km southof the town (Sarikamis South), on the border of the Araxes Valley (Bigazzi et al. 1998): the domeof Ciplak Dag (outcrops close to the village of Mescliti and along the road between Karakurt andSarikamis) and the Ortatepe dome (outcrops close to Sehitemin; Sevindi 2003). The latest

Table 3 Separated and overlapping outcrops according to the different diagrams

Source Zr–Ba diagram Nb/Zr–Y/Zr diagram Ba/Zr–Ba/Sr diagram

Arteni Split into three groups Split into two groups Split into three groupsAshotsk Separated Separated SeparatedHatis Overlap with Süphan Dag,

part of Sarikamis Southand part of Chikiani

Overlap with Chikiani andGutansar

Partial overlap with part ofTsaghkunyats

Gegham Separated Separated Overlap with part of Syunikand Khorapor

Gutansar Overlap with part ofSarikamis South

Overlap with Hatis andChikiani

Separated

Chikiani Overlap with Tsaghkunyatsand part of Hatis

Overlap with Gutansar andHatis

Separated

Sarikamis North Split into two groups;overlap with Meydan Dagand Tendürek

Split into two groups;overlap with Meydan Dagand Sarikamis South

Split into two groups

Sarikamis South Split into two groups;overlap with Süphan Dag,Hatis and Gutansar

Split into two groups;overlap with Tendürek,Meydan Dag, Süphan Dagand Sarikamis North

Split into two groups

Syunik Split into three groups; oneof them overlaps withKhorapor

Separated Split into three groups; oneof them overlaps withKhorapor and Gegham

Tsaghkunyats Split into two groups;overlap with Chikiani

Split into two groups Split into two groups;overlap with part of Hatis

Khorapor Overlap with one of theSyunik group

Separated Overlap with Gegham andpart of Syunik

Süphan Dag Overlap with Hatis and partof Sarikamis South

Overlap with SarikamisSouth

Separated

Tendürek Overlap with Meydan Dagand Sarikamis North

Overlap with SarikamisNorth and South

Overlap with part of MeydanDag

Meydan Dag Overlap with Tendürek andSarikamis North

Overlap with SarikamisSouth

Overlap with part ofTendürek



episode (between 3.8 and 3.5 Ma) is attested by two obsidian outcrops located closer to the town(Sarikamis North), near the villages of Handere and Hamamli.

In order to check the hypothesis of an origin in the region of Sarikamis, on the next diagramswe compare the Akhurian River samples with those from the Sarikamis South outcrops, and withvalues published by other authors for the different Sarikamis obsidian deposits (Keller andSeifried 1990; Keller et al. 1996; Gallet 2001; Delerue 2007) (Figs 6 and 7).

From these diagrams, it appears that the first chemical group defined for the Akhurian River(Akhurian 1) matches the composition of the Handere obsidian outcrops, while the Akhurian 2group matches the composition of the Hamamli outcrops. All these obsidians belong to theSarikamis North sources.

In the same way, our Sarikamis South 1 group appears to be close of the Sarikamis 1 groupdefined by Keller, while our Sarikamis South 2 group matches the composition of the Mescitli/Sehitemin outcrops and appears to be close to the Sarikamis 2 group defined by Keller. All theseobsidians belong to the Sarikamis South sources. The Ba/Zr versus Ba/Sr diagram appears to bethe stronger in differentiating these different outcrops (Fig. 7).

It then appears that the Shirakavan pebbles have the same composition as other pebbles foundin the Kars River near Akbaba Dag and that this composition is characteristic of the SarikamisNorth obsidian deposits, which are situated at the springs of the Kars River (Gallet 2001). Thusthe chemical analyses confirm the hypothesis that these obsidian pebbles were carried down bythe Kars River.

Arteni complex

The Arteni complex is located in the south-western part of the Aragats volcanic massif. Twomajor eruption centres—Mets (Big) Arteni (2047 m) and Pokr (Small) Arteni (1753 m)—represent a multiphase volcanic field formed by repeated eruptions of rhyolitic magmas. Theprominent example is the 7–8 km long Aragats flow of Mets Arteni, which is dominantly perlitic,

0

0.05

0.10

0.15

0.20

0.25

0 0.2 0.4 0.6

Nb/Zr

Y/Z

rChikiani

Damlik

Tvakar

Kamakar

Aïkasar

Figure 5 The binary diagram of the Nb/Zr–Y/Zr ratios for the Chikiani and Tsaghkunyats outcrops.



with parts of the flow solidified as obsidian. Obsidian blocks occur also in the pumice deposits ofthe earliest phases of Arteni volcanism, such at Brusok (Keller et al. 1996). Satani Dar (TapakBloor) was formed as a result of one of the separate volcanic eruptions (Blackman et al. 1998).

The dates show that the different sources were formed successively between 1.4 and 1.1 mya(Komarov et al. 1972; Wagner and Weiner 1987; Oddone et al. 2000; Badalyan et al. 2001;Chernyshev et al. 2006).

The Arteni obsidians range from uniform opaque black to opaque grey, grey–brown,red, banded black and red, and translucent. The material is very abundant and of the highestquality.

Several different compositional groups, which appear to be comagmatic, were obtained for theArteni obsidian outcrops (Fig. 8). This volcanic complex thus appears to be one of the moredifficult ones to characterize. Three main chemical groups could be derived from our data andfrom those published by Keller (Keller and Seifried 1990; Keller et al. 1996). The first (Arteni 1),characterized by low barium and zirconium concentrations, is equivalent to the Arteni 1A definedby Keller. The obsidian from this group comes from the outcrops of Satani Dar and Mets Arteni.The second group, characterized by higher barium concentration, is equivalent to Keller’s Arteni1B group as defined in 1990, but not in 1996. The last group, which contains the highest amountof barium, corresponds to Keller’s Arteni 1C group. The latter two groups contain obsidian thatoriginates from both the Pokr Arteni and Aragats flow, this is probably due to an error insampling, as these flows are difficult to distinguish in the field. Therefore a new systematicsampling and a new set of analyses would be necessary.

0

100

200

300

400

500

600

0 50 100 150 200 250 300

Zr ppm

Ba

pp

m

Hatis

Gutansar

Akhurian 1 Handere

Akhurian 2 Hamamli

Handere (Delerue 2007)

Handere (Gallet 2001)

Hamamli (Gallet 2001)

Sarikamis 1

Sarikamis 2

Mescitli and Sehitemin (Delerue 2007)

Mescitli (Gallet 2001)

Sarikamis 1 (Keller and Seifried 1990)


Figure 6 The binary diagram for the Zr–Ba contents of Akhurian obsidian and the obsidian outcrops sampled in theregion of Sarikamis.



0

5

10

15

20

25

30

0 2 4 6 8 10Ba/Zr

Ba

/Sr

Hatis

Gutansar

Akhurian 1 Handere

Akhurian 2 Hamamli

Handere (Delerue 2007)

Handere (Gallet 2001)

Hamamli (Gallet 2001)

Sarikamis 1

Sarikamis 2

Mescitli and Sehitemin (Delerue 2007)

Mescitli (Gallet 2001)



Figure 7 The binary diagram of the Ba/Zr–Ba/Sr ratios of Akhurian obsidian and the obsidian outcrops sampled in theregion of Sarikamis.

0

50

100

150

200

250

300

350

400

0 20 40 60 80

Zr ppm

Ba p

pm

Arteni 1, Satani Dar and Mets Arteni

Arteni 2, Pokr Arteni and Aragats flow

Arteni 3, Pokr Arteni and Aragats flow

Arteni 1A (Keller)

Arteni 1B (Keller)

Arteni 1C (Keller)

Figure 8 The binary diagram of the Zr–Ba contents for the Arteni outcrops; comparison with data published by Keller(Keller and Seifried 1990; Keller et al. 1996).



Gutansar complex

The Gutansar complex is found to the north of Yerevan and covers a large area between thevolcano itself and the left bank of the Hrazdan River, which flows from Lake Sevan towardsthe Araxes. This complex contains several volcanic domes (Gutansar, Fontan, Alapars, Aivazan,Dzhraber and Gyumush) that erupted during a relatively short period between 310 000 and240 000 years ago (Wagner and Weiner 1987; Oddone et al. 2000; Badalyan et al. 2001, 2004).

The Gutansar samples present a wide range of colours from uniform black to grey, grey–brown, brown, banded black and red, mottled black and red. The flows are very abundant andcontain enormous blocks of obsidian of usually high quality.

All the obsidian from the Gutansar complex forms a homogeneous chemical group that iseasily distinguished from the other Armenian obsidian groups in terms of their zirconium andbarium concentrations. We notice just a slight overlap with the Sarikamis 2 group of obsidian,which is easily resolved by using their Ba/Zr–Ba/Sr ratios (Fig. 7). The chemical analysesconfirm the exceptional homogeneity of the different Gutansar sources, making it practicallyimpossible to distinguish among them, given the margin of error that accompanies the analyticalresults.

A flow from the Gutansar volcano spread south-east as far as the foot of the Hatis volcano,which is 6 km away. Samples collected in this region have been attributed alternatively to Hatisand to Gutansar. However, the chemical compositions, which are quite distinct, make it possibleto correct the geological origins of these samples.

Hatis (or Atis)

At Mt Hatis (2529 m), at least two phases of activity have been recognized: (a) approximately700 ka ago, the formation of the Hatis volcano—the composition of the obsidian corresponds tocalc-alkaline rhyolites; (b) about 50 ka ago, the intrusion of small obsidian dykes that cross-cutacid volcanic rocks produced earlier (Arutyunyan et al. 2007). Poidevin (1998) has distinguishedthree subgroups: Hatis I and Hatis II belong to the first phase of activity; while Hatis III, avitreous rhyolite enriched in rare earth elements, belongs to the second phase.

The obsidian is grey to grey–brown on the south-western flank and black on the southern slope(Blackman et al. 1998). The Hatis III samples contain some mineral inclusions (feldspars) thatare visible to the naked eye; these samples are not suitable for knapping (Pitois 1998; Badalyanet al. 2004).

The obsidian from the Hatis Mountain is represented by two groups that are easily differen-tiated by their strontium content. The first one (Hatis 1), with lower strontium concentrations(about 81 ppm), originates in the western outcrops (Akunk and Kaputan), while the second one(Hatis 2), with higher strontium contents (136 ppm), comes from the south-eastern slopes(Zerborian).

Gegham Mountains (Geghasar, Spitaksar)

Spitaksar (3560 m) and Geghasar (3446 m) are large volcanic domes that are located in thesouthern part of the Gegham volcanic highland and are about 6 km apart. In volcanic structure,eruptive mechanisms, products and age, the two volcanoes show strong similarities. The obsidianflows spread along the flanks of the domes and at their feet, on the high plateaus that are locatedat ~3000–3200 m and covered with steppic vegetation. These plateaus are densely populated



during the summer by transhumant herders who come there to put their herds out to pasture, butare inaccessible from mid-October to the end of May, because of a stable snow cover that is about2 m thick on average. However, a mountain stream has its source at the very foot of Geghasar onits north-west flank and carries numerous blocks of obsidian towards the Azat River, where theyare deposited and then carried further to the south and to the Ararat plain.

These obsidian flows are the most recent in Armenia and are dated to between 80 000 and40 000 years ago for Geghasar and 120 000 years ago for Spitaksar (Komarov et al. 1972;Badalyan et al. 2001).

Macroscopically, the obsidians from Geghasar and Spitaksar are very different. At Geghasar,the obsidian presents various colours (translucent, uniform grey, red, banded brown and black).At Spitaksar, the obsidian contains numerous crystalline inclusions, which make it more difficultto work because the small crystals block the waves of force transmitted by percussion, and theforms of the flakes detached are problematic.

The obsidians from Geghasar and Spitaksar form a homogeneous chemical group. The diffi-culty in distinguishing between them on the basis of their composition indicates that theyoriginate from the same magmatic chamber and that they evolved very little during the 40 000years or so that separated the two volcanic eruptions. This obsidian is characterized by very lowzirconium and barium values (Figs 2 and 9), but is easily differentiated from the Syunik andKhorapor obsidians in terms of their Nb/Zr and Y/Zr ratios (Fig. 3).

Khorapor (Vardenis)

Located on the northern slopes of the Vardenis range, south-east of Lake Sevan, Khorapor is adome-shaped volcano. Reaching an elevation of 2906 m, it rises in a region of high plateaus,which it overlooks by only a few hundred metres. This highland region is covered by snow frommid-November to the end of May; thus the volcano is accessible only during the summer.

The obsidian, dated from 1.75 to 1.53 Ma (Komarov et al. 1972; Badalyan et al. 2001), isfound both at the summit of the dome and on the flanks of the volcano.

0

10

20

30

40

50

0 50 100

Zr ppm

Ba p

pm

Gegham

Khorapor

Bazenk

Mets Satanakar

Pokr Sevkar and Mets Sevkar

Figure 9 The binary diagram for the Zr–Ba contents of the Syunik, Khorapor and Gegham outcrops.



This obsidian is of poor quality to work, since it contains many crystalline inclusions andgenerally consists of small nodules within a rhyolitic matrix. No artefacts have been found on thisdeposit.

The obsidian from Khorapor is close in composition to those from the Gegham Mountains andfrom the Syunik complex (Figs 9 and 10). They could, however, be differentiated on the basis oftheir Nb/Zr and Y/Zr ratios (Fig. 3).

Syunik complex (Satanakar group, Sevkar group and Bazenk)

The Syunik sub-zone involves large volcanoes of distinct morphology, including MetsSatanakar, Michnek Satanakar, Pokr Satanakar, Mets Sevkar, Pokr Sevkar (or Sevkar foothills)and Bazenk.

The longest and thickest flows are those at Mets Sevkar and in ‘the foothills of Pokr Sevkar’.This latter term is used because the obsidian deposit is near the dome of Pokr Sevkar, but morerecent deposits of basalt cover most of the surrounding landscape and the relation of the obsidianto Pokr Sevkar is uncertain. One hypothesis is that this deposit was part of the great flow emittedin this direction by Mets Sevkar (Badalyan et al. 2004). The mountain streams that descend fromthese high plateaus and join the Vorotan River carry blocks of obsidian; in the valley, manyobsidian pebbles can be collected from the river. At Godedzor, about 30 km from the obsidianoutcrops, a certain number of artefacts bear strips of neo-cortex (surface ground down bymovement in the river) and the reduced size of most of them shows that the pebbles found in theVorotan were actually exploited by the Chalcolithic inhabitants of this settlement.

The Syunik sources (Satanakar, Sevkar and Bazenk), date from 0.61 to 0.43 Ma (Komarovet al. 1972; Badalyan et al. 2001).

The obsidian, abundant and of high quality, is dark grey to jet black and translucent whenthinly flaked; at the Sevkar sources, there are significant occurrences of red–brown mottling(Cherry et al. 2008).

20

30

40

50

60

10 20 30

La ppm

Ce p

pm

Gegham

Khorapor

Bazenk

Mets Satanakar

Pokr Sevkar and Mets Sevkar

Figure 10 The binary diagram for the La–Ce contents of the Syunik, Khorapor and Gegham outcrops.



The obsidian from the Syunik complex forms three close chemical groups (Fig. 9), whichcorrespond, respectively, to the outcrops of Bazenk (Syunik 1), Mets Satanakar (Syunik 2) andMets Sevkar and Pokr Sevkar (Syunik 3). These groups can be discriminated on the basis of theirconcentrations of the lighter rare earth elements (especially La and Ce) and Th (Cherry et al.2008) (Fig. 10). As stated above, the obsidian from Bazenk shows some chemical similaritieswith the Gegham Mountains obsidian.

Tendürek

Tendürek is an isolated polygenetic volcano (3584 m), built by small fissure eruptions followedby central eruptions and caldera collapse. The rocks are predominantly basalts and trachyandes-ites; however, a small obsidian flow (30 cm thick) is mentioned between two trachytic eruptions(Yilmaz et al. 1998). This obsidian flow is visible on the northern flank of the volcano, at about15 km south-west of the city of Dogubeyazit.

Very few samples from the Tendürek have been analysed so far (Frahm 2010). All the obsidiansamples provided by M. Glascock come from a single flat area on the eastern flank of theTendürek. This deposit is distinct from the outcrop mentioned by Yilmaz et al. (1998) on thenorthern flank.

Meydan Dag

The Meydan Dag (2722 m) strato-volcano is Pliocene in age and is characterized by a summitcaldera, the south-eastern rim of which is interrupted by a Middle Pleistocene obsidian dome,from which an obsidian lava flow originates, presenting a 5-km-wide front. The south-easternflank of the volcano, east of the road coming down from the caldera above the village of Ziyaret,is scattered with obsidian blocks (Belli 2001).

The obsidian is almost devoid of any microcrysts. It is black and brown (Matsuda 1988).The obsidian that comes from the Tendürek and that from the Meydan Dag volcanoes are close

in terms of their Sr,Y, Zr, Nb and Ba compositions, but they could be easily differentiated by theiriron and rubidium contents (Table 4, first part).

Süphan Dag

The Süphan Dag (4434 m), which represents the second highest elevation in Turkey, is located atthe intersection of two major faults. It is a polygenetic strato-volcano made up of a complex ofmany eruptive domes and cones with intercalated lava flows and pyroclastics, the lavas rangingin composition from basalt to rhyolite. The most recent products consist of obsidian domes andlava flows, dated to about 0.7 Ma (Pearce et al. 1990; Bigazzi et al. 1998). They are located onthe north and south-western part of the main zone. Mount Nernek, situated to the south of MountSüphan, has also produced obsidians, together with rhyolitic and perlitic lavas (Ercan et al.1996).

The obsidian from the Süphan Dag volcano has a dark-grey colour, which is due to anexceedingly thick felt of acicular iso-oriented crystal. White oligoclase inclusions and well-formed opaque tabular crystals, sometimes visible to the naked eye, are widespread (Fornaseriet al. 1975–7).

The obsidian samples provided by M. Glascock come from three different places near toHarmantepe (south-west of the volcano).



Table 4 Average compositions and standard deviations for each compositional group. The number of samplesanalysed for each group is given in brackets. Reference values used for Nist and corning glass standard are given in

the two first lines. All elements are in ppm, except for Na2O, MgO, Al2O3, SiO2, K2O and CaO, which are givenas % oxides

Source Li B Na2O MgO Al2O3 SiO2 K2O CaO Ti Mn Fe Zn Rb Sr Y Zr Nb

Nist 610 glass Referencevalues

484 351 13.4 0.08 2.0 69.9 0.06 11.6 434 433 457 456 431 497 450 440 419

Corning B glass Referencevalues

105 17.0 1.03 4.4 62.3 1.00 8.6 630 1 936 2 378 1526 161

Arteni 1 Average (18) 69.3 44.3 4.29 0.05 13.6 75.4 4.09 0.54 331 687 3 281 46.2 143 7.9 21.1 35.9 36.3

Satani Dar andMets Arteni

SD 4.6 3.6 0.24 0.002 1.2 0.8 0.17 0.06 15 40 433 6.8 7 0.7 1.7 3.1 2.5

Arteni 2 Average (13) 55.9 41.2 3.98 0.06 13.1 76.2 4.23 0.59 440 542 3 850 39.2 122 14.3 15.7 48.4 28.2

Pokr Arteni andAragats flow

SD 3.4 3.9 0.21 0.003 0.3 1.2 0.19 0.07 33 43 209 3.9 10 1.3 0.7 2.6 1.8

Arteni 3 Average (7) 50.8 42.6 4.03 0.08 13.1 76.0 4.39 0.63 526 514 4 179 50.5 122 22.6 14.6 52.0 25.9

Pokr Arteni andAragats flow

SD 4.6 9.1 0.01 0.03 0.1 1.1 0.11 0.08 29 31 420 13.2 3 2.6 1.7 7.7 0.7

Ashotsk Average (8) 31.2 22.9 4.16 0.37 15.2 72.6 4.01 1.42 1 855 412 11 766 42.0 94 142.7 12.2 192 17.7

SD 2.6 4.4 0.14 0.02 0.7 0.5 0.13 0.06 65 39 756 5.9 5 5.7 1.4 25 1.3

Hatis 1 Average (8) 49.3 27.6 4.32 0.18 14.1 75.3 3.88 0.99 626 462 6 184 36.8 108 81.7 10.4 62.7 21.4

SD 4.4 7.0 0.13 0.02 0.2 0.2 0.07 0.11 18 26 924 3.7 7 5.6 0.8 3.7 1.7

Hatis 2 Average (8) 54.4 26.0 4.24 0.40 15.0 73.8 3.70 1.45 1 027 462 9 839 38.0 92 133.9 10.0 86.2 19.9

SD 4.7 4.9 0.08 0.01 0.4 0.8 0.04 0.10 41 35 558 4.7 8 6.8 0.6 6.3 1.0

Gegham Average (20) 80.3 44.6 4.27 0.05 13.5 76.0 4.22 0.59 373 604 3 515 31.2 191 6.6 15.4 42.4 47.2

SD 8.6 5.2 0.10 0.01 0.4 0.9 0.07 0.07 19 73 353 4.2 13 0.9 1.9 5.3 3.5

Gutansar Average (24) 63.6 30.9 4.34 0.22 14.6 74.7 3.80 0.94 1 002 566 8 048 40.9 137 87.3 15.3 121 33.5

SD 8.0 5.5 0.20 0.02 0.7 0.5 0.09 0.10 71 51 943 5.9 9 12.2 1.8 13 2.2

Chikiani Average (19) 44.9 25.4 4.08 0.10 13.5 76.0 4.42 0.68 605 443 4 922 48.2 127 54.8 9.1 60.1 18.4

SD 13.1 3.4 0.17 0.01 0.6 0.6 0.11 0.16 53 17 511 11.9 6 5.5 0.8 5.8 1.6

Sjunik 1 Average (6) 73.1 18.8 4.22 0.04 13.5 76.9 4.07 0.46 370 471 4 946 34.1 174 3.0 5.9 60.8 34.9

Bazenk SD 10.5 3.6 0.36 0.01 0.3 0.6 0.23 0.08 18 15 2 341 1.6 15 0.6 0.5 7.6 2.2

Sjunik 2 Average (2) 72.8 23.6 4.16 0.05 12.8 77.0 4.24 0.49 484 510 4 696 46.0 193 5.6 6.5 57.2 34.8

Mets Satanakar SD 3.3 3.2 0.19 0.004 0.5 0.5 0.26 0.05 9 182 1 0.1 0.8 1.0 0.1

Sjunik 3 Average (13) 56.6 25.3 4.08 0.05 13.3 76.1 4.20 0.54 522 391 4 260 31.4 167 11.3 6.5 63.6 30.0

Mets Sevkar/Pokr Sevkar

SD 5.1 4.1 0.08 0.002 0.2 1.1 0.05 0.06 40 22 286 7.5 8 0.9 0.7 3.9 1.9

Tsakhkunjats 1 Average (10) 45.4 26.3 4.28 0.12 13.4 75.8 4.20 0.86 612 437 5 622 32.4 103 115.9 6.1 64.6 20.5

Damlik/Ttvakar SD 3.9 3.9 0.12 0.01 0.3 0.6 0.09 0.05 48 31 914 1.4 9 18.5 1.0 10.7 2.0

Tsakhkunjats 2 Average (10) 34.0 22.4 4.22 0.18 14.3 74.9 4.12 0.88 842 377 7 613 33.5 84 175.1 6.2 111 18.5

Aïkasar/Kamakar

SD 5.0 3.5 0.23 0.01 0.6 0.5 0.09 0.09 41 36 403 3.1 6 18.3 0.6 9 0.4

Khorapor Average (1) 86.8 39.3 4.04 0.04 12.6 77.7 4.38 0.67 483 4 349 205 2.1 11.4 67.3 35.9

SD

Akhurian 1 Average (2) 50.3 27.9 4.79 0.06 13.2 76.0 4.21 0.44 583 650 7 120 67.1 136 6.0 31.5 143 26.1

Handere SD 2.5 0.1 0.01 0.01 0.7 0.6 0.05 0.06 9 17 3 0.8 2.5 14 1.0

Akhurian 2 Average (12) 51.6 26.5 4.50 0.03 15.4 74.3 4.13 0.31 474 603 7 633 72.2 130 2.0 35.4 168 26.9

Hamamli SD 8.0 1.9 0.24 0.004 1.6 1.3 0.09 0.05 44 22 539 5.9 5 0.7 3.1 18 1.3

Sarikamis 1 Average (7) 46.4 29.8 3.89 0.10 13.2 76.6 4.49 0.49 792 236 7 147 26.7 135 16.5 19.2 106 14.7

SD 6.2 1.7 0.14 0.004 0.3 0.3 0.09 0.07 120 35 1 246 2.5 16 2.1 1.4 6 1.1

Sarikamis 2 Average (7) 37.2 23.0 3.80 0.06 15.0 75.6 4.19 0.41 478 337 4 789 32.1 121 16.8 16.2 70.2 12.4

Mescitli/Sehitemin

SD 4.4 2.1 0.26 0.004 1.8 1.4 0.20 0.04 62 47 775 4.8 9 1.7 1.0 10.8 0.5

Süphan Dag Average (11) 65.5 45.7 4.02 0.04 13.0 75.9 4.23 0.48 430 219 11 725 44.2 128 9.3 19.0 72.7 8.5

SD 2.7 1.4 0.19 0.001 0.4 0.9 0.15 0.04 39 27 3 318 2.4 25 1.6 1.6 11.4 0.3

Tendürek Average (9) 74.4 30.9 4.89 0.05 13.0 75.2 3.63 0.34 431 481 16 333 87.6 122 6.9 26.1 168 23.5

SD 9.1 2.5 0.09 0.004 0.5 0.5 0.37 0.03 24 27 937 0.7 3 0.7 3.5 20 1.4

Meydan Dag Average (10) 89.4 40.4 4.59 0.05 13.5 76.0 3.95 0.36 448 477 9 564 75.5 183 11.8 43.4 230 32.3

SD 12.7 12.0 0.09 0.005 0.3 0.4 0.03 0.05 31 31 726 13.3 18 3.2 11.1 48 3.8



Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta Th U Ba/Zr Ba/Sr Nb/Zr Y/Zr

361 424 457 448 430 431 451 461 420 443 427 449 426 420 462 435 418 377 451 457

660

4.2 30.1 8.4 23.1 2.2 8.1 2.9 0.26 3.1 0.65 4.4 0.92 2.7 0.43 3.2 0.44 2.2 2.3 11.6 8.8 0.84 3.8 1.02 0.59

0.4 4.0 0.9 1.8 0.2 1.0 0.4 0.3 1.3 1.1 0.09 0.3 0.09 0.03

3.4 142 12.2 29.2 2.5 8.9 2.2 0.25 2.1 0.41 2.7 0.58 1.7 0.27 2.0 0.27 2.3 1.8 11.2 7.4 2.94 10.0 0.58 0.32

0.3 10 0.9 1.5 0.1 0.8 0.1 0.06 0.1 0.05 0.1 0.03 0.1 0.04 0.1 0.04 0.2 0.1 1.0 0.9 0.21 0.5 0.02 0.01

3.4 274 14.6 34.5 2.9 9.9 2.2 0.36 2.1 0.44 2.5 0.57 1.6 0.32 1.9 0.30 2.4 1.5 10.9 7.1 5.31 12.2 0.51 0.28

0.4 31 1.4 1.9 0.2 0.6 0.6 0.2 1.5 0.7 0.43 0.6 0.08 0.03

2.3 752 41.8 71.3 6.1 21.3 3.4 0.85 2.7 0.41 2.5 0.52 1.6 0.25 1.8 0.30 5.5 1.1 15.8 3.8 3.97 5.3 0.09 0.06

0.3 25 2.4 3.5 0.2 1.6 0.2 0.02 0.2 0.02 0.3 0.05 0.2 0.01 0.2 0.01 0.7 0.1 2.8 0.4 0.58 0.3 0.01 0.00

4.4 450 21.2 41.4 3.4 11.5 2.0 0.47 1.7 0.29 1.8 0.39 1.2 0.19 1.4 0.20 2.6 1.8 13.5 10.1 7.20 5.5 0.34 0.17

0.4 24 1.2 1.7 0.2 0.8 0.1 0.2 2.1 1.1 0.53 0.3 0.02 0.02

3.4 465 24.6 45.6 3.8 13.1 2.1 0.45 1.8 0.30 1.9 0.40 1.2 0.18 1.4 0.21 2.8 1.6 13.6 8.2 5.42 3.5 0.23 0.12

0.4 41 1.8 3.9 0.3 1.0 0.1 0.07 0.1 0.02 0.1 0.03 0.1 0.01 0.0 0.01 0.3 0.1 1.1 0.7 0.68 0.4 0.01 0.01

7.2 8.7 12.4 28.2 2.4 8.7 2.2 0.16 2.0 0.40 2.7 0.56 1.7 0.26 2.0 0.28 2.1 3.9 19.5 15.5 0.21 1.3 1.13 0.37

0.8 0.9 0.9 1.5 0.2 0.7 0.1 0.01 0.1 0.03 0.2 0.05 0.2 0.01 0.2 0.03 0.4 0.4 3.6 2.3 0.04 0.2 0.17 0.06

5.0 363 24.9 50.3 4.2 14.3 2.7 0.48 2.3 0.43 2.9 0.59 1.8 0.29 2.3 0.33 3.9 2.5 14.3 10.4 3.03 4.2 0.28 0.13

0.6 25 2.7 3.5 0.5 1.2 0.2 0.04 0.2 0.03 0.3 0.05 0.2 0.03 0.2 0.03 0.5 0.2 1.9 1.0 0.19 0.4 0.02 0.01

4.4 543 17.8 39.1 3.4 11.4 2.1 0.53 2.1 0.33 1.8 0.36 1.1 0.16 1.2 0.17 2.4 1.4 11.6 6.2 9.08 9.9 0.31 0.15

0.5 65 2.0 3.5 0.3 1.0 0.1 0.09 0.4 0.04 0.2 0.04 0.1 0.02 0.1 0.01 0.2 0.2 1.6 0.5 1.13 0.5 0.04 0.02

4.9 3.3 14.1 26.0 2.0 4.7 0.6 0.05 0.5 0.09 0.6 0.16 0.6 0.12 1.1 0.17 3.2 2.0 27.8 12.7 0.06 1.2 0.58 0.10

0.8 0.5 1.0 1.5 0.1 0.2 0.1 0.01 0.0 0.00 0.0 0.01 0.0 0.01 0.1 0.01 0.4 0.1 5.4 1.3 0.01 0.4 0.04 0.02

5.0 12.7 21.0 38.5 2.6 7.0 0.9 0.09 0.7 0.14 0.8 0.18 0.6 0.13 1.1 0.18 2.6 1.9 26.8 12.7 0.22 2.3 0.61 0.11

0.3 0.2 0.8 0.2 0.2 2.1 0.00 0.1 0.01 0.02

4.3 31.6 24.3 46.7 3.1 8.7 2.7 1.6 23.8 10.9 0.50 2.8 0.47 0.10

0.5 4.0 1.6 2.6 0.2 1.1 0.5 0.2 1.9 1.4 0.05 0.2 0.02 0.01

3.5 586 28.3 53.7 4.2 12.7 1.8 0.25 1.2 0.22 1.1 0.26 0.6 0.15 0.9 0.14 2.5 1.5 21.8 11.3 9.12 5.1 0.32 0.10

0.4 76 4.4 5.2 0.5 1.4 0.4 0.1 5.3 1.8 0.35 0.2 0.04 0.02

2.8 895 43.9 74.0 5.6 16.3 2.0 0.43 1.2 0.19 1.1 0.22 0.7 0.11 0.9 0.14 3.1 1.2 24.5 9.0 8.08 5.2 0.17 0.06

0.4 38 2.7 3.8 0.4 1.3 0.1 0.04 0.1 0.02 0.1 0.02 0.0 0.01 0.1 0.02 0.3 0.1 2.6 0.3 0.53 0.5 0.01 0.00

6.8 2.0 18.8 36.1 28.2 17.0 0.03 0.9 0.53 0.17

4.4 95.1 31.0 70.0 6.3 23.4 5.2 0.43 4.9 0.92 6.1 1.26 3.9 0.65 4.4 0.62 5.5 1.6 15.1 6.9 0.67 15.9 0.18 0.22

0.3 11.4 4.3 1.3 2.3 0.8 0.02 0.3 0.01 0.00

4.4 29.3 33.1 68.2 6.4 23.5 5.2 0.25 4.8 0.91 6.0 1.29 3.8 0.57 4.4 0.66 5.6 1.5 16.8 6.8 0.18 15.8 0.16 0.21

0.7 5.3 7.3 13.5 1.3 4.3 0.7 0.06 0.6 0.08 0.4 0.09 0.2 0.05 0.4 0.06 0.4 0.1 1.7 0.6 0.04 4.0 0.02 0.03

4.4 287 27.4 52.9 4.8 14.4 2.9 0.24 2.5 0.45 3.0 0.69 2.0 0.33 2.5 0.38 4.1 1.1 20.6 8.8 2.70 17.5 0.14 0.18

0.2 30 4.6 2.7 0.4 1.5 0.0 0.01 0.0 0.01 0.0 0.05 0.1 0.01 0.0 0.00 0.7 0.0 4.2 0.9 0.22 2.0 0.01 0.02

4.0 391 21.8 40.1 3.6 12.5 2.4 0.32 2.3 0.39 2.6 0.57 1.7 0.23 2.1 0.30 2.8 0.9 15.6 6.8 5.64 23.4 0.18 0.23

0.2 41 4.6 4.5 0.4 1.5 0.3 0.05 0.2 0.05 0.3 0.06 0.1 0.04 0.2 0.05 0.4 0.0 3.5 1.0 0.80 2.8 0.03 0.02

4.2 389 19.7 43.6 4.1 17.2 3.8 0.35 3.4 0.56 3.8 0.70 2.2 0.29 2.5 0.32 2.9 0.8 12.9 4.3 5.44 42.6 0.12 0.27

1.2 20 1.4 3.3 0.3 1.4 0.2 0.04 0.3 0.06 0.3 0.07 0.2 0.04 0.2 0.04 0.2 0.1 1.0 0.7 0.60 6.4 0.01 0.03

4.1 37.1 18.0 40.8 3.9 19.7 4.4 0.22 4.3 0.72 5.3 0.93 3.3 0.41 3.6 0.47 5.3 1.6 15.2 4.7 0.22 5.3 0.14 0.16

0.2 3.5 2.0 3.2 0.4 2.2 0.6 0.04 0.7 0.10 0.7 0.12 0.5 0.06 0.5 0.06 0.7 0.1 1.9 0.4 0.02 0.1 0.01 0.00

8.4 46.0 26.6 63.7 6.4 23.7 5.3 0.29 4.8 0.92 5.9 1.26 3.7 0.59 4.4 0.63 6.3 2.8 21.3 8.7 0.21 4.0 0.14 0.19

0.5 9.2 3.9 4.2 0.3 2.7 0.4 0.02 0.4 0.07 0.4 0.08 0.2 0.04 0.3 0.06 0.7 1.7 2.4 0.6 0.05 0.6 0.02 0.01



The Süphan Dag obsidian forms a homogeneous chemical group that has zirconium andbarium contents similar to those of the Hatis and Sarikamis 2 obsidian (Fig. 2), but has a farhigher Ba/Sr ratio (Fig. 4).

CONCLUSION

Twenty-two different chemical groups are thus defined from our geological corpus (as previouslymentioned in Table 1): seven for eastern Turkey (if we consider that the Akhurian River second-ary deposit is not truly an Armenian source, but has a Turkish origin), 14 for Armenian obsidianand one for Georgian obsidian. Two different compositional groups are obtained for both theTsaghkunyats and the Hatis volcanoes, while three different groups are defined for Arteni andSyunik. For eastern Turkey, at least four different compositional groups originate from thesurroundings of Sarikamis. Average compositions and standard deviations obtained for thedifferent groups are given in Table 4.

This study of obsidian sources in the southern Caucasus and eastern Turkey shows that the dataare still fragmentary, and that new geological surveys on certain deposits are necessary (espe-cially on the sources of Arteni in Armenia and of Sarikamis and Yaglica Dag in the province ofKars in Turkey). Knowledge of the locations and of the characteristics of the different eruptiveepisodes is essential in order to obtain an exhaustive and reliable geological database, enablingthereby precise determination of the origins of the artefacts.

The analytical results confirm that visual examination cannot enable a discrimination of thenumerous obsidian sources in this region. Indeed, the different varieties (texture and colour)belonging to the Gutansar complex form a homogeneous chemical group, whereas the samevarieties found on various obsidian sources belong to different chemical groups.

If we refer to the barium and zirconium contents, obsidians in this large territory split into fourmain groups, which show, in Armenia, an increase in the barium content from the south-east(Syunik) to the north-west (Ashotsk). Thus the following groups can be distinguished:• a group with low contents (<100 ppm) in barium and zirconium—Syunik, Gegham, Khoraporand part of Arteni;• a group with low barium contents (<100 ppm) and middle to high zirconium contents(125–300 ppm)—Tendürek, Meydan Dag and Sarikamis North (secondary deposits of theAkhurian River);• a group with middle to high barium contents (175–700 ppm) and low to middle zirconiumcontents (50–150 ppm)—Gutansar, Hatis, Chikiani, Sarikamis South, Tsaghkunyats 1 (Damlik,Ttvakar) and part of Arteni; and• a group with high barium contents (>700 ppm) and mid-ranging zirconium contents(100–200 ppm)—Ashotsk and Tsaghkunyats 2 (Kamakar, Aïkasar).

In most of the sources, a ‘continuum’ of the barium contents (and often the zirconium contents)is observed, either within the same chemical group (Chikiani, Gutansar) or between the variouschemical groups of the same magmatic chamber (Syunik, Arteni).

The method used to differentiate the compositional groups of obsidians is based on simplebinary diagrams, which combine contents (Zr–Ba) and ratios (Nb/Zr, Y/Zr, Ba/Zr and Ba/Sr).This method enables quick discrimination between the obsidian sources exploited by the inhab-itants of the archaeological sites studied. However, when these elements do not allow thedistinction between sources of very close compositions, as is the case for Syunik, Khorapor andGegham, the large number of elements determined by LA–ICP–MS always allows us to findother element couples that give a clear separation of these outcrops.



ACKNOWLEDGEMENTS

The authors express their gratitude to the French Ministry of Foreign and European Affairs andthe Academy of Science of Armenia, which provided financial backing for their work in Armenia.They are sincerely grateful to Marie-Claire Cauvin (CNRS, Lyon), Catherine Kuzucuoglu(CNRS, Meudon), Catherine Marro (CNRS, Lyon) and Michael Glascock (University of Mis-souri Research Reactor Center) for providing geological samples of obsidian.

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