Browsing by Author "Akkopru, Ebru"

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The Importance of the Geomorphological and Volcanological Indicators in Determining Obsidian Source Areas
(Tmmob Jeoloji Muhendisleri Odasi, 2017) Akkopru, Ebru; Mouralis, Damase; Robin, Anne-Kyria; Kuzucuoglu, Catherine; Erturac, M. Korhan
As understood from the artifacts found in the archaeological excavation areas, the obsidian belonging to the volcanic areas of the Eastern Anatolian Region spread to a very wide area by being traded in prehistoric times. For this reason, it is important to carry out a study on obsidian diffusion and volcanic-geomorphological features in the Eastern Anatolia Region. In this study, the importance of volcanological and geomorphological indicators in the determination of obsidian sources is given by examplifying field studies with geomorphological and geological approaches in the volcanic areas of Eastern Anatolia Region The basic characteristics of obsidian (color, texture, durability, hardness, etc.) presence, quantity and availability as raw materials are closely related with volcanic and geomorphological processes. For example; The chemical and physical properties of the obsidian appear largely under the control of volcanism. Magmatic processes play an important role in the spread of the obsidian surface areas and in the formation types (dom, dyke, flow, etc.). The presence of obsidian in a volcanic massif is the result of volcanism, but at the same time, its continuation in the same area later also depends on the type and severity of the entire erosion process. Namely, the next volcanic activity and or erosional processes in the volcanic area may cause the obsidian to fossilize or be completely eroded and destroyed. In addition, this kind of effect also changes the presence and proportion of obsidian in the colluvial and alluvial material known as secondary sources on the area.
Lake Van
(Springer international Publishing Ag, 2019) Akkopru, Ebru; Christol, Aurelien
Lake Van is the largest soda lake in the world. It is a terminal lake, surrounded by mountains rising to 3500 m a.s.l. The Lake Van Basin is divided into three geological and morphological units: (1) the mostly metamorphic Bitlis Massif pertaining to the Bitlis suture zone to the south-west; (2) Mesozoic and Tertiary rocks (carbonates and volcanics) between the lake and the Turkish-Iranian border, and (3) volcanoes and volcanic products extending from the west to the north-east of the lake. The variety of the geomorphological landscapes around the lake is exceptionally high, with (i) some of the most impressive dormant volcanoes of Turkey; (ii) young (Late Pleistocene to recent) volcanic features such as a lake-filled caldera on top of the beheaded Nemrut Volcano, the solitary Suphan Volcano (the "Tushpa" God of the Urartians which dominates the lake by >1000 m), the fresh basaltic lava flows of the Tendurek Volcano, etc.; (iii) extensive lake terraces filling large valleys where they record impressive variations in lake level at least since the last 200 ka; (iv) travertine mounds associated with fault lines and river valleys; (v) karstic landscapes in the Bitlis Range and in the Tertiary limestones to the north-west, where they are covered by Nemrut ignimbrites and Suphan basalt and obsidian flows; (vi) glacial imprints on the summits of the Bitlis Range and of the Suphan; (vii) active landslides in marine sediments forming the slopes in the south-eastern basin; (viii) strong influences of tectonics on the relief, etc. Like in all Eastern Anatolia, high altitude pastures attract since millennia long-distance migrations of sheep herds seasonally switching between the southern plateaus in Syria and Iraq in winter, and Eastern Anatolia and the Caucasus in summer.
Obsidian Outcrops From Nemrut Volcano (Eastern Anatolia): Evidence in Favor of an Exploitable Source, First Results
(Groupe Francias Geomorphologie, 2015) Robin, Anne-Kyria; Mouralis, Damase; Kuzucuoglu, Catherine; Akkopru, Ebru; Gratuze, Bernard; Dogu, Ali Fuat; Cetoute, Joel
Archeological studies have demonstrated that many Prehistoric artefacts in obsidian found in the Near East have a chemical affinity with obsidian out-cropping in the Nemrut volcano. In the archaeological literature, Mount Nemrut is considered as one of the most important obsidian sources used by prehistoric societies. During our two field works in 2013 and 2014, we prospected a wide area on and around Nemrut volcano. Our findings confirm the location of the obsidian outcrops described in the literature. According to our observation, obsidian on Mount Nemrut volcano is generally not exploitable for chopping tools. Most of the studied obsidians we defined on the field, present a facies with numerous phenocrysts and cracks, which is not compatible with a good knapping quality. However, we identified a new outcrop associated with obsidian artefacts such as nuclei and rough flakes. Geological samples of the obsidian from this outcrop present all a very different fades compare to those of others Mount Nemrut obsidians: obsidian from this area does not show any phenocryst or cracks, and they are very homogeneous and uniform. These characteristics are in favor to knapping criteria. Comparatively to the other known obsidian outcrops in the Nemrut volcano, we can assume here that this obsidian outcrop is, to date, the only source one that could have been exploited, by Prehistoric people on the Nemrut volcano. Our work, using chemical analyzes (LA-ICP-MS), petrology and field observation enhances characteristics for workable obsidian that depends on the modality of emplacement. This last one should have been different from the other outcrops to provide a different facies.