The stable isotope records from Lakes Zeribar and Mirabad were the first reported from the Quaternary of Iran. Millennial-scale shifts in both overall moisture availability and timing of atmospheric precipitation have been well documented. My students and I, in collaboration with Antje Schwalb (Institut für Umweltgeologie Technische Universität Braunschweig, DE), are continuing our research on Lake Mirabad. The main objective is to look at hydrologic changes in the central Zagros Mountains at decadal resolution and to explore any cycles and relationships to societal upheaval in early civilizations of Mesopotamia.
This project aims to reconstruct centennial-scale hydrologic variability in the mountains of northern Iran from the stable-isotopic composition of sediments from Lake Urmia, Iran. The Taurus-Zagros Mountains present a topographic barrier to storm systems bringing precipitation from the Mediterranean Sea. As such, they are the headwaters of several major river systems, including the Tigris-Euphrates and Sirvan/Dylan, which provide agricultural and municipal water for millions of people throughout the Near East. The mountains also serve as the major recharge site for several regional ground water aquifers. In historical times, collapse of major civilizations have been attributed to precipitation changes in the mountains and drought in the Mesopotamian lowlands. The same stresses that resulted in cultural upheaval 4000 years ago are still evident today.
Over 100 meters of sediment have been recovered during a recent engineering analysis.
The results of the stable isotope portion of the project will be linked to a vegetation study being conducted at IMEP-CNRS, France by Ph.D. student, M. Djamali, under the direction of Dr Jacques-Louis de Beaulieu. Sedimentology is being directed by Dr. Abdol Hossein Amini and his student, Madjid Shah-Hosseini, at the University of Tehran.
Lake Urmia today is a shallow, hyper-saline system that resembles the Great Salt Lake, Utah, USA. Sedimentary analyses suggest that the lake has undergone periods of freshening that would be related to wetter climates in the past. Picture at left is of salt mounds along the shore. Photo courtesy of M. Djamali.
Artemia (brine shrimp) (at left) contribute fecal pellets (at right) to the sediment. The pellets are almost pure aragonite and can be used for stable isotope analysis. Photos are courtesy of M. Djamali and M. Shah-Hosseini.