GEOARCHAEOLOGY, ENVIRONMENTAL HISTORY, AND TECTONIC UPLIFT IN EASTERN ANATOLIA (SE TURKEY)

The Eastern Anatolian (or Turkish-Iranian) Plateau of southeastern Turkey contains some of the most impressive and high elevation landforms associated with the active Alpine-Himalayan orogen, and is the headwater region for the Tigris and Euphrates River Systems. The geomorphic evolution of these important drainages reflects the interplay of surface processes and tectonics -- the development of topographic relief and lithospheric deformation since the closing of the Southern Neo-Tethyan (or Bitlis) Ocean. Hence, the study of these "Big Rivers" is an important proxy for deep crustal processes associated with mountain building and volcanism along the continent-continent plate collision zone. This paper synthesizes new observations about the geomorphic development, environmental history, and archaeology of this region, which preserves artefacts in stratigraphic contexts dating from the prehistoric Middle Stone Age to the Iron Age (Assyrian and Urartu Kingdoms), through the Achaemenid (Persian) Empire and later periods (Medieval-Islamic). Field survey, mapping, and geochronology across the Upper Tigris Basin enable (1) description of the modern and ancient landscape elements, including fault scarps, valley fills, scroll bars, floodplains, etc; (2) assessment of hydrologic, paleoclimatic, and cultural archives for reconstructing patterns of environmental and tectonic change. Delineation of Quaternary deposits and dated contexts will be presented reach-by-reach along a regional transect commencing at the Tigris Source near Lake Hazar, and moving downstream through the Bitlis suture zone, and through the terrain that is part of the Arabian Plate near Batman. The evolution of the Upper Tigris drainage over the past ~13 Myr can be reconstructed as a function of vertical movement (e.g. base-level changes, tectonic uplift, doming, downwarp, and sagging), horizontal deformation (e.g. folding, faulting, compression, and extension), volcanism, weathering, and erosion (e.g. dissolution processes, karstic erosion, and sapping). It is important to assess the first-order tectonic controls on the evolving fluvial systematics of the Tigris so that its sedimentary and geomorphic records can be used to accurately reconstruct hydroclimatic changes affecting this part of the Near East during antiquity.