Study of the Relations of the Ancient Communities with Landscape in the South and West Sides of the Sevan Lake Area (Armenia)

Study of the relations of the ancient communities with landscape in the South and West sides of the Sevan Lake area (Armenia)

Neda Parmegiani CNR Istituto di Studi sulle Civiltà dell’Egeo e del Vicino Oriente, Rome, Italy Maurizio Poscolieri CNR, Istituto di Acustica “O. Corbino”, Rome, Italy formerly, INAF, Istituto di Astrofisica Spaziale e Fisica Cosmica, Rome, Italy

Keywords: archaeology, Armenia, Urartu, Landsat TM, DEM, tectonics, landscape reconstruction

ABSTRACT: An interdisciplinary project, known as “Urartu Project” and aimed at reconstructing the Urartian civilisation (IX-VII centuries BC), has been set up since 1994 by the CNR ICEVO in the region of the Lake Sevan (Armenia). Within it a landscape archaeology analysis of the study area has been performed by integrating information coming from monitored sites and thematic maps, including LANDSAT t TM images, a Digital Elevation Model (DEM), a geological map and other ancillary data taken from literature and Internet. These data permitted to obtain digital maps which, integrated with geological and tectonic information, have provided support in terms of interpretation to the mentioned archaeological results. The relationships of sites with morphology have been investigated by analysing a DEM, generated by the interferometric processing of an ERS tandem (~20 m/pixel). It has been processed to derive shaded relief maps, to investigate surface morphological differences expressed as discontinuities in relief. Another aspect examined has been the land cover and land use characteristics of the whole area, which have been analysed by means of False Colour Composite (FCC) of geocoded LANDSAT TM bands. Moreover, by applying suitable data fusion procedures to the described data sets and to a bathymetric map of the Sevan lake new digital products have been created to improve the interpretation key of landscape with respect to the archaeological sites distribution on the area.

1 INTRODUCTION

The results of a Landscape Archaeology study, that the CNR-ICEVO and INAF-IASF institutes have been performing since seven years on the area surrounding the Lake Sevan (Armenia), are presented. This study is a part of a project, carried on by the ICEVO since 1994, aiming at reconstructing the Urartian nation (IX to VII centuries B.C). The Urartian civilization in its maximum extension included eastern Turkey, Armenia and Iranian Azerbaijan (Fig. 1). Within the Urartu project there is the reconstruction of the ancient landscape in the area surrounding the Lake Sevan, identified as the eastern frontier of Urartian kingdom. The results, concerning the southern part of the Lake Sevan (in the ex-rayon – province – of Vardenis and Martuni), have been published in the book series Documenta Asiana (ICEVO, 2002). The present study concerns mostly the ex-rayon of Kamo, nowadays Gavar, located along the western coast of Lake Sevan, nearby the lake shrinking, dividing it into two parts, Greater and Lesser Sevan. The landscape analysis has been carried out by integrating information coming from archaeological sites and thematic maps, which include LANDSAT TM images, a DEM, a geological map and other ancillary data from literature and Internet. The analysis of these data sets and their comparative interpretation, performed with respect to the archaeological sites distribution on the area, have

621 Figure 1. Location of the study area.

provided a preliminary appraisal of the environment parameters, basic for settlement location choices of ancient populations.

2 ARCHAEOLOGICAL FRAMEWORK

The investigation has given insight into the organization of the populations in the territory, located mostly at south of the Lake Sevan, documenting 83 “sites” (fortresses, forts, settlements, necropolis), ranging from the Early Bronze Age to the Medieval period. During more recent field campaigns (2001-2004), carried out in the Gavar area, along the western coast of the lake, 27 pre-Middle Age sites (forts, necropolis, etc.) have been inspected and 22 analysed (see Fig. 3). The analysis of archaeological data has stressed a different organization of the landscape control in the two areas. The Gavar area and the southern side of the lake were both inhabited since the Early Bronze Age, but a preliminary archaeological analysis, concerning Early Iron Age sites, has highlighted some differences, between the two locations, expressed in terms of number of urban hierarchical levels. In fact, in the Gavar area (land of Uelikukhi and Luehu Tulihu) only two levels were present, lacking completely the intermediate size, occurring instead in the whole southern Sevan side (Fig. 2). In this area four different clusters of sites have been identified according to historical and architectural evidences: all together seem to be associated into a confederation (known as Ueduri-Etiuni). The Gavar area is characterized by an hummocky plain encompassed between the Gegham ridge and the lake western coast line. The identified sites lie mainly in the eastern side of the region, where most of rivers and waterlands occur. The western sector, exhibiting a lower amount of water, appears gently sloping and presents large areas covered by herbaceous vegetation, but the settlements are rare: it is mostly utilized for cattle-breeding.

622 N. Parmegiani & M. Poscolieri Archaeological site Inscription IŠTIKUNIU Modern place ˇ QEHUNI LIQIU Ancient toponym Sevan LIQIU Lake Lcaˇ šen

Hrazdan “19 kings on the other side of the lake” Gavar Sevan UELIKUHI ˇ

LUEHU Vardenis ˇ TULIHU ˇ Tsovak Vardadzor Martuni Tsovinar ARQUQINI ˇ LUERUHI ˇ URTEHINI 0102030 Km

Figure 2. Lake Sevan in the Urartian period (sketch map by A. Mancini).

Figure 3. Geo-structural sketch map of the Gavar area (after Karakhanian et al., 2003), with superimposed the archaeological sites, whose names are listed aside.

Study of the relations of the ancient communities with landscape in the South and West sides 623 3 GEO-STRUCTURAL SETTING

As already mentioned, the sites are located between the western coast of the Lake Sevan and the eastern slopes of the Gegham volcanic ridge, characterized by a high density of lava domes and pyroclastic cones (Pleistocene – Holocene age). The volcanoes and associated lava flows cover an area extending 65 km (N-S) by 35 km (E-W), west of the Sevan Lake and south of the Hrazdan river, along three alignments with NNW-SSE orientation. Lavas starting from the eastern and central volcanic clusters area flew into the lake. Early explosive eruptions were followed by extrusion of domes and ryolithic obsidian lavas. More recent activity produced the emplacement of a series of lava flows and cinder cones of andesytic and basalt-andesytic composition. The eastern and central portions of the Gegham ridge include large areas covered by lava flows dating back to Holocene, morphologically fresh and without vegetation cover (Fig. 3). From the geo-structural viewpoint Lake Sevan is a large pull-apart basin enclosed between two large W–NW-striking active faults to the north and south (Fig. 4). Both faults are right strike slips with a combination of reverse components on their northern and southern sides. Shorter systems of oblique active faults occur on the lake flanks to the west and to the east. These systems are a combination of strike slips and normal faults. The faults form grabens. A DEM of the lake bottom suggests the presence of a system of NE normal faults arranged in stepped grabens (see Fig. 5, Karakhanian et al., 2001).

Pambak-Sevan

Artanish

Sevanlake Sunik fault Gavan

3521 m. Vardenis

Figure 4. Geo-structural scenario of the area surrounding Lake Sevan (after Philp et al., 2001).

The formation of the basin dates back to Holocene and is still in progress, as it is evidenced by several morphologic deformations, by the seismic activity and by the Holocenic and historic volcanism (Krakhanian et al., 2001).

4 DATA PROCESSING

The digital data sets utilized in this landscape study have been: • a DEM, generated by the interferometric processing of an ERS1-2 tandem pair, acquired on 23- 24 August 1998, and arranged as a SLC (single look complex) product. The DEM has been, first, georeferenced with respect to the Krassovsky ellipsoid (spatial resolution of ~20 m/pixel) and, then, with respect to the UTM WGS84 system. A peculiar by-product has been a shaded relief obtained by choosing a sun azimuth of 120° and zenith angle of 67°. This thematic map has been colour coded taking into account the elevation and has been, then, utilized to evaluate the

624 N. Parmegiani & M. Poscolieri Figure 5. FCC of LANDSAT TM bands 7-4-2 with overlapped the examined sites.

Figure 6. Shaded relief, obtained from a DEM generated by the interferometric processing of an ERS1-2 tandem pair, choosing a sun azimuth of 120° and zenith angle of 67°. This thematic map has been colour coded taking into account the elevation.

morphological setting of the area in relation with the geological and tectonic structures, inferred from literature and a geologic map on a scale of 1:200,000 (see Fig. 6); • a mosaic of a FCC (False Colour Composite) of the LANDSAT TM 7-4-2 bands, georeferenced in the UTM WGS84 coordinate system; this data set has been recorded in 1990 and made available by NASA in Internet on the MrSid WEB site for all over the world. The FCC has allowed to perform a visual analysis (therefore, partial) of the landscape, evidencing, however, landforms, vegetated areas, land use, urban areas and water bodies;

Study of the relations of the ancient communities with landscape in the South and West sides 625 • a geo-structural sketch map of the study area, which has been co-registered with respect to the LANDSAT TM FCC, transformed in vector format (Fig. 3) On all the digital data the archaeological sites have been overlapped on the basis of their geographical coordinates and viewed in 3D representation after draping LANDSAT FCC and shaded relief on the DEM. Moreover, a data fusion of Lake Sevan bathymetry with LANDSAT scene has been carried out to verify the continuity of tectonic features on both sides of the lake (Fig. 5). The compared investigation of all acquired data sets has allowed to attain a preliminary confirmation of the hypothesis on the influence of the landscape morpho-structural characteristics on the geographical distribution of the archaeological sites. As an example the sites belonging to Uelikukhi and Luehu Tulihu lands appear separated by a structural lineament, with NE-SW orientation, crossing also the lake bottom.

5 PRELIMINARY RESULTS AND CONCLUSIONS

This preliminary work step has allowed to analyse the spatial distribution of Iron Age forts and fortresses: the majority of them are located within a “spindle-shaped” area (Fig. 3), bounded eastward by the lake level variations (where only tombs and necropolises have been found) and westward by the occurrence of the Gegham volcanic ridge. These sites lie east of the, N-S elongated, natural escarpment, parallel to the south-western lake coast line, connected to the S-SE stretching tectonic lineament of Gavar (Figs 3, 5 and 6). Northward this lineament verges to NW, where many volcanic edifices, mostly seated to the North, are aligned. This feature seems to represent the S-SE location limit of most sites. Out of all sites the Urartian fort of Arghuiti Dasht (n. 10 in Fig. 3) appears peculiar because of its interior location south of the cited N-S/NW-SE structural lineament, lying on a feeble tactical position, on low-relief terrain easy to be conquered. This means that the fort function was not military but administrative, perhaps devoted to gather and store the products brought by local communities to Urartian people as tributes. Nowadays the area is mostly devoted to cattle-breeding and this fact together with the particular site location and the presence of Urartian pottery suggest that the fort could be built by Urartians after the campaign of Rusa I king (about 730 B.C.) which represented the beginning of peaceful period in the Lake Sevan region. According to Trifonov and Karakhanian (2004) active faulting can influence the human life and social development, first of all, as a source of strong earthquakes and accompanied phenomena such as ground deformation, landslides and sometimes volcanism. In the Eastern Mediterranean and the Middle East, since the ancient time, many archaeological sites appear located near active fault zones or in basins, which are bounded by active anticlines with blind thrusts in cores. Active tectonism seems related to the presence of good soils in suitable fields, sources of water and the seed material for planting, which were also necessary for the agriculture. Active faults formed steep bounds of intermountain basins and foredeeps with springs and good soils on alluvium. Within tectonically unquiet regions wide-spread active faults created numerous relatively steep slopes, linear depressions, closed or semi-closed basins and other landscape features suitable for agriculture, either providing migration routes for ancient man groups of people or impeding free passage from one territory to another. Moreover, on the areas of active faulting a major exhalation of endogenous gases occurs, together with a higher geothermal flux. This yields an impact on local microclimate, especially in areas with markedly cold weather, where land can be exploited only for a very few months: conditions typical of the Lake Sevan region (Fig. 7). The presented study, even if at a preliminary stage, has highlighted the effectiveness of geocoded digital data sets as complementary tools to confirm or give strength to the archaeological hypotheses.

626 N. Parmegiani & M. Poscolieri First millenium B.C. As of 1998

Desert Semi-desert Steppe Forest Sub-Alpine Alpine km2 14000 12000 1000 800 600 400 200 0 Redistribution of vegetation zones in Armenia Figure 7. Map of the distribution of vegetation zones in Armenia, during the first millennium B.C. and nowadays.

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