International Journal of Earth Sciences Knowledge and Applications

Yazarlar: Parisa NAMİ, Shahriyar KARİMDOUST, Ekrem KALKAN

Konular:-

Anahtar Kelimeler:Lake Urmia,Evaporitic deposits,Clastic sediments,Aragonite,Gypsum

Özet: Lake Urmia, as the largest and saltiest permanent lake in Iran, being also known as one of the world’slargest and saltiest lakes, has emerged after the last glacial period due to the tectonic activity ofcompressive faults specially Tabriz and Zarrineh-Rud faults in the northwest of Iran. This relativelyyoung lake has stone foundation being composed of limestone and marlstone without any folding Qom Formation in Miocene Epoch on which about 30 meters of soft lake sediments are deposited.More than 80% of these deposits are chemical and evaporative along with mainly aragonite, calcite,and halite minerals with biological origin. The presence of clastic thin layers consisting of quartz,feldspar and kaolinite, especially at the entrance points of the rivers, indicates temporary climatechange and lake salinity. The thickness of the evaporitic sediments has remarkably increased withdepth decrease in the southern part of the lake along with the increase in evaporation, causing theemergence of more than 56 small and large islands in this part of the lake. Succession of evaporiticsediments in some parts of the lake has deposited sulfate minerals such as gypsum and anhydrite invery fine shapes. In addition, in the swampy areas of the lake, sulfur sediments can also be seen assedimentary laminates.

---