Geodiversity Assessment in Catchments of Salt and Hoz-e-Soltan Lakes

Extensive scientific studies in the field of geodiversity are underway today, reminding the international community of the growing importance of identifying and protecting these geological heritages. Therefore, the expansion of studies related to geodiversity, especially in Iran, which has a lot of geological and geomorphological richness, can open a new window in the field of recognizing natural potentials. Watersheds and mountainous areas dominated by salt lakes and Hoz-e-Sultan are among the areas that have a very diverse geological and geomorphological diversity, so studies of these areas with geodiversity approaches and valuation of these areas using the index In addition to creating a new approach to natural studies in these areas, geodiversity measures as well as land use metrics allow planners to maintain well-planned planning, as well as development planning, especially tourism and Educationally design appropriate decision-making for these areas. Study area The study area includes catchments and elevations overlooking Hoz-e- Soltan and Namak lakes. Which includes the heights of the northwest of the region and overlooking the Sultan Basin (Unit 1). Unit 2 is located southwest of Salt Lake. Unit 3 includes the heights of the southeast of the Salt Lake and includes three separate sections, and the Yakhab heights are one of the most important areas in this section. The fourth unit is located east and northeast of Salt Lake and consists of two units.

This research is descriptive and analytical. The boundaries of the catchments of the studied units were prepared using the Alos-Plasar digital elevation model with a spatial resolution of 12.5 m and using the ArcHydro plugin in ArcGis10.7 software. In this study, six criteria were used to assess geodiversity: geology, fault, topographic position index (TPI). In order to analyze the geodiversity in the study area, a set of quantitative methods of geodiversity indicators and land use measurements were used. In the analysis of geodiversity index (GD), the method of Serrano et al. 2009 was used. In calculating the Landscape metrics, seven indicators used in this research including the roughness density of each piece (PRD), Simpson roughness index (SIEI), Shannon N roughness index (HEI), Shannon diversity index (SHDI), Simpson diversity index (SIDI), index Modified Simpson N (SIEI), Simpson Modified Diversion Index (MSIDI).

the average geodiversity index results show that the values of the highest average geodiversity among the studied units belong to units 4-1 with a geodiversity value of 2.85, followed by 1-3 with 2.6 and 3-3 with 2.47, respectively. the lowest average value among the units belongs to unit 1-1 with 0.156. If we consider each unit as a whole and zone, we can say that in the catchments overlooking the Salt Lake and Sultan Basin, unit 4 with an average geodiversity value of 2.55 has the highest value and then respectively Unit 3 with a decrease of 2.496, Unit 1 with a value of 1.25 and finally Unit 2 with a value of 0.66 are in the next ranks. In order to rank the units from the perspective of land use metrics, the average of all variables in each unit was calculated (Table, 6). Based on this, from the PRD measurement point, unit 1-1 with an average of 0.329 has the highest value. In the scales, SHDI (1.640) and MSDI (1.366) and in the RPR scale, the highest values belong to unit 2 (22) and unit 3-3 in the scales 0.814 (SIEI), SHEI (0.862, and MSIEI0.721) ) And in the SIDI scale (0.66) the highest values belong to units 1-4. In general, according to the study of the average of each zone, Zone 2 with the highest values in the RPR, SHDI, SIDI and MSIDI scales from the point of view of land use scales has the highest score and then Zone 3 with two SHDI and MSIEI and Zone 1 in PRD and Unit 4 in SIEI are one in the next ranks.

One of the most important advantages of the geodiversity index compared to land use measurements can be considered as segmentation of different areas of a map based on the unit of cell, which allows better display of geodiversity value of each cell. Each unit allows the zoning of different parts of a unit from a geodiversity perspective and provides researchers with a more detailed analysis of the geodiversity values in each unit, while considering the land features of a unit as a whole. And provides only the ability to provide geodiversity values for a unit. In addition, considering the roughness coefficient in the geodiversity index simultaneously with the studied element, can enter the equation of the role of topographic factor in better geodiversity analysis of each cell and provide a better evaluation of the land landscape measure.