The ongoing changes affecting Lake Urmia (NW Iran) are revealed by the lake water level decrease (∼7 m in the last 20 yr) that was attributed to natural and anthropogenic causes but the exact impact of these factors on the state of the lake is still not identified. Indeed, lack of detailed record of environmental evolution of the lake in the past limits the understanding of actual and future processes. Our project aims to obtain a high-temporal resolution record of environmental changes in the lake area for the last ∼30 kyrs. Sediment cores have been obtained from the recently dried out part of the lake near Urmia City, and surface and ground waters have been measured for electric conductivity. This paper presents results of water and sediments analyses. Six ¹⁴C AMS dating on organic fractions provide a chronological framework and indicate that the record covers the last ∼30 cal kyr BP. During this period, evaporitic conditions were prevailing in the lake. The electric conductivity of brines from the sediment highlights changes in the lake water salinity. The data indicate a lake-level low stand at ∼30 cal kyr BP that was followed by a water level rise and establishment of lacustrine conditions for the next ∼9 kyr, this phase representing the highest lake level recorded since that time to date. From the LGM, the lake experienced several fluctuations of the water level. The relatively long-term lacustrine condition established during the Early Holocene before the water level decrease between ∼5.5 and 4.9 cal kyr BP. Sediments from the two dry events at ∼30 cal kyr BP and at 5.5–4.9 cal kyr BP are characterized by the presence of greigite, which indicates anaerobic early diagenetic conditions in the sediment.

由于自然和人为原因，湖水位下降（最近20年约7 m）揭示了影响Urmia湖（伊朗西北部）的变化。仍未确定。确实，过去缺乏对湖泊环境演变的详细记录限制了对实际和未来过程的理解。我们的项目旨在获得最近30个月内湖区环境变化的高温分辨率记录。沉积岩心是从乌尔米亚市附近最近干out的部分湖泊中获得的，并且已经对地表水和地下水的电导率进行了测量。本文介绍了水和沉积物分析的结果。六个¹⁴对有机馏分进行的C AMS测年提供了一个时间框架，并表明该记录涵盖了最后30卡尔·基尔BP。在此期间，湖中普遍存在蒸发条件。来自沉积物的盐水的电导率突显了湖水盐度的变化。数据表明，湖水处于约30千卡BP的湖面低位，随后水位上升，并为下一个约9千瓦建立了湖泊条件，这一阶段代表了自那时以来所记录的最高湖水位。在LGM中，湖泊经历了水位的几次波动。在全新世早期建立的相对长期湖相条件，水位在约5.5至4.9千卡BP之间下降。两次干燥事件的沉积物在约30 cal kyr BP和5.5–4时。