Investigation of morpho-sedimentary features of Kalshour River’s fan, Northeastern Iran: Emphasizing Quaternary climatic controls

Climate has an important role in the sedimentation of quaternary fans. In the dry climate of the present time, the surface materials of the hills have deposited during the wet or cold periods, but these deposits have been transferred to alluvial fans during the transition to dry or warm periods of Quaternary (Bull, 1991). Instead, in the present basins that are located in semi-arid climates, sediments have been transferred to fans during the wetter or colder period. Alluvial fan’s deposits are sensitive to hydrological conditions, and the study of these sediments provides worthwhile information from paleo climate. Quaternary sediments of the alluvial fans offer important information about paleoclimates conditions and paleo environmental changes of their catchments.

In this research, the authors have studied the evolution of sedimentary pattern using the results of geophysical and geochemical analyses on the surface of the Kalshour Fan in the Northeast of Iran, during the Quaternary period. The Kalushshour fan is a small and relatively symmetrical fan in the southern slopes of the Binaloud Mountain Range in North eastern Iran (Fig.1 and 2). This area is closed to city of Neyshabour (20 km) at latitude with latitude 36 ° 10'35 "N to 36 ° 12'36" N and longitude 58 ° 59 '6 "E to 59 ° 0' 11 "E. The mean annual precipitation in the region surrounding the study area is 15 to 28 cm/year(source: Meteorological Organization of Khorasan Razavi, Iran ), suggesting that the study area lies in the arid to semiarid transitional zone. The focus of this research is on the Kalshour basin on the southern slopes of the Binaloud mountains and alluvial fan and terraces. And attempts to compare the dispersion of the major and trace element oxides with the standard averages of these sediments present.
The first map of the study area was prepared in the ArcGIS 10.3 software based on aerial photographs, topographic maps and satellite images to study the alluvial fan surface. Then different levels of geomorphological surfaces were determined according to the colour, texture and grain size parameters. Then, during the field trips, the accuracy of the map Validated with the reality on the ground and its bugs were met.
Eight samples were collected from the surface of the alluvial fan for studding of their geophysical and geochemical characteristics. Chemical analyses were performed for eight samples. Analyses were performed by x-ray influence spectrometer and inductively coupled plasma-mass spectrometry (ICP-MS) at the Bespar Payesh (Mining Material Research Co), Analytical Laboratories Ltd. in Ferdowsi university of Mashhad, Iran. The main oxides are in% and trace elements in ppm. Based on morpho-sedimentry characteristics, the surface of this fan is classified into 8 levels, called A1 to A8.
After drying the sediment in the oven, sediments were weighted at intervals of 0.5 to 5 phi. Then, other parameters related to the sediment texture, sedimentation, degradation, sorting, etc. were determined, and the associated analyses and diagrams, such as percentage cumulative graphs, percentages, etc. were mapped using the Gradistate software. To ensure the results obtained, the graphs of the name and texture of the sediment were re-constructed in the 3Dplot software environment. To improve the achievement, the corresponding graphs in the Corel DRAW Graphic Suitee software environment were restored and Set up. At the next step. Their findings were compared together.

 Based on the geophysical analysis, A2, A5, A6, and A7 samples are poorly sorted and stretchy than the rest of the sediments. Elemental geochemistry well describes the temperature and precipitation of paleo conditions. Also according to the geochemical analysis, the amount of calcium, aluminum, and silica oxide elements and the ratio of magnesium to calcium and manganese to calcium in samples A1, A3 and A8 were decreased and in s A6, A2, A5 and A7 samples were decreased Which in turn reflects the cold - dry and warm - humid climate. In general, according to the results of geophysical and geochemical analyses, carrier flood in the A6, A2, A5 and A7 sediment samples had been passed with very high speed. Also, these floods occurred in a climatic environment with a physical watering regime. In A4, A1, A3 and A8 samples, warm and humid climate were associated with continuous but less energetic floods. Thus, four sedimentary levels due to the cold and dry environment and four sedimentary levels due to the warm and humid environment are visible at the surface of the cone.