نوع مقاله : مقاله پژوهشی
1 استادیار ژئومورفولوژی، گروه جغرافیای طبیعی، دانشگاه زنجان
2 کارشناس ارشد هیدروژئومورفولوژی، گروه جغرافیای طبیعی، دانشگاه زنجان
عنوان مقاله [English]
The dewatering and hydrological conditions of the basins, in addition to the climate, depend on the physiographic and geological conditions. The emergence of numerous lakes with different origins in large areas is possible, but in a basin with an area of the Ghezloosen, it is a rare and uncommon thing. Known identity some of them are just spatial viwepoint. In this study, with a spatial viewpoint, the classification of the lake's morphogenesis and the multivariate effects of the environment and geomorphologic processes in the emergence of each of them. The basins area of Qezelowzan is among the Caspian Sea sub basins. The variation in lithology and faults has led to the formation of different conditions in this basin, so that has contributed to the formation of different landforms. One of the processes involved in the formation of landforms is stagnant waters, which is referred to as the process of the lake.
Materials and Methods
For investigate the factors to create or to change of Qezelowzan basin lakes, the DEM 30 * 30 and extracted from the USGS, and topographic maps of 1: 50,000 and 1: 100000 geological and 1: 250000 was used. Using Arc GIS & an Arc map was digitized the layers such as waterway network, lithology, and faults. Using the Google Earth software, water aggregation sites were identified and their area was mapped or reconstructed, and the length, width, and area of each of them were calculated. For the reasoning of glacial lakes, the quaternary permanent boundary was estimated using the Wright and Porter method and based on this, the height of the equilibrium line was also determined. In Qaleh chai area more than 9 glacial lakes were identified. Granulometry was performed to confirm and document glacier lakes on local sediment samples.
Discussion and results
The basin area of Qezelowzan is more than 50 thousand square kilometers. The location of this basin is such that the junction and interference of morphtectonic land units of Central Iran, Alborz, Northwest of Iran, Sanandaj-Sirjan and Zagros. Such a situation leads to the emergence of different landforms influenced by many internal and external processes such as volcanoes, fracture, rupture, glacial, landslide, and changing levels are basically in the basins. Among these landforms, what is discussed in this article is landforms related to stagnant waters. The location of the accumulation of runoff in a region is recognizable by the convergent waterway network, which can be scarified after the evolution of the lake, with the help of the surface levels and the drains and the remaining convergent drainage network (Fig. 3). According to such evidence, 22 lakes were identified in the catchment area of Qezelowzan. 2 Kurd bad lakes in the Tarom area, 2 lakes in the southeastern slopes of the Sahand volcano, 9 lakes in Qalehchai, 6 lakes in Dandy, and 6 lakes as geonurons in the Qezelowzan.
The results indicate that lakes of glacier, volcanic, landslid, chimestry and topographic origin are formed in 50,000-square-meter basins. The fault lines and mountins trands in this basin are such that Qezelowzan has to cut off their axis to reach the Caspian Sea. These conditions have triggered a period of time from places such as Bijar, Zanjan, Mianeh and Tarom as local lakes. Volcanic activity has caused the formation of two Almalo and Chogar Lakes in the this basin. The hight elevation of the different parts of the basin and the latitude above that area have provided for the quaternary glacial processes. In the part of the basin where the height and lithology conditions were favorable, the glacial could create U-shaped valleys, with the retreat of the glacier, the conditions for the capture of some of them were provided and created a lake. Most of these lakes have disappeared at the time of glacier retreat by changing the level of local rivers and domination of desertification erosion in the region. The earthquake of 1986 in the Tarom-Manjil region has created several lakes, one of which is the Kurd bad or Baklour Lake, which has slipped lakes by blocking part of the Ghangolichay River route. Changes in the water inputs of these lakes have caused them to become lakes only during the year. These lakes can be a living proof that during the Quaternary, Pasadenian orogeny movements created the final form of the Alpine-Himalayan fissures, causing numerous lakes to land on strikes that have been lost due to overflow.