نوع مقاله : مقاله پژوهشی
1 استاد گروه ژئومورفولوژی، دانشکده علوم زمین، دانشگاه شهید بهشتی تهران.
2 پژوهشگر پسادکتری، دکتری ژئومورفولوژی، دانشکده علوم زمین، دانشگاه شهید بهشتی تهران.
3 کارشناسی ارشد ژئومورفولوژی، دانشکده علوم زمین، دانشگاه شهید بهشتی تهران.
عنوان مقاله [English]
Geodiversity can be defined as the natural diversity of geology (rocks, minerals, fossils), geomorphological (land form, physical processes), and soil properties. This combination includes sets, relationships, properties, interpretations, and internal systems. Geodiversity emphasizes biodiversity and provides the community with the benefits of regulating, supporting, providing cultural services and services, and with a set of actions to inform the management of geological sites, including inventory and assessment, conservation, legal protection, interpretation and monitoring of sites strives to preserve landscapes and the environment. Karaj Dam Basin is a natural area in which human intervention is very low up to the Karaj Dam. Recent research has investigated the extent of geodiversity and diversity of geosites in the upstream basin of Karaj Dam with the aim of environmental management.
This research has been done using data extracted from Landsat 8 images, Aster elevation data and field surveys. The research method included assessing the diversity of Karaj Dam basin using PR (Patch Richness), SHDI (Shannons’s Diversity Index) and SIEI (Simpson’s Evenness Index). In this way, a 25 km cellular network has been placed on the basin. The purpose of this operation was to create smaller units to calculate the result of the indicators more accurately. In the next step, using the typology method in terms of intrinsic value, the sample geodiversity representative and geological dimensions have been identified and evaluated. In this regard, visual observations, field sampling and Landsat 8 image have been used in the following criteria.
Results and Discussion
The results of the study of selected geodiversity indicators showed that the area around the Karaj Dam Lake and the south of the basin are more suitable conditions in terms of the number of classes obtained. These results are based on the visible bands of the Landsat image and the elevation model. The PR index, which shows the natural richness of the earth, means the presence of diversity, which is shown in visible images. The maximum of this diversity is observed around Karaj Dam Lake and south of the basin. The SHDI index is an index used to describe the diversity of species in a community (Sarma and Das, 2015, 635) and And the SIEI index, which indicates the probability that random features belong to different species (Goudarzian and Erfanifard, 2017, 10) And the SIEI index, which indicates the probability that random features belong to different species, is also calculated based on the color spectrum diversity of the visible bands, which theoretically represent the diversity of the ground or geodiversity. On average, in the cells that had the most replication among the indicators in the very high geodiversity class, the height and slope also varied. To study the earth typology in terms of vulnerability and protection of geosites, although sampling has been done from the whole basin, but according to the above results, most of the field observations have been made around the lake and south of the basin. In this regard, by examining geological and geomorphological maps, Landsat 8 satellite images and field observations, features and sites of the basin were identified. Based on origin in lithology, hydrogeology, geomorphology, stratigraphy and tectonics, as well as by shape; Point, section, area, viewpoint, and complex were classified. After identifying the sites and classifying them, the values of each site, including tourism, science, and protection were evaluated. Each site can have a variety of values within it that need to be protected. Geosite protection can be beneficial in terms of ecotourism and tourism and revenue generation.
The geodiversity of Karaj dam basin was evaluated by PR, SHDI and SIEI indices. The results showed that the Karaj dam basin has a significant geodiversity that is closely related to landforms. The results of typological analysis and vulnerability assessment in Karaj dam basin lead to the identification of point features such as waterfalls near roads, main rivers and geological features of this basin due to increased construction (road construction, recreational areas, restaurants and restaurants) or caves which are prone to destruction due to dumping of waste and garbage. Most of the geosites in Karaj Dam are on a point scale, which are very vulnerable, and in the next stagevare section, they are also more vulnerable, and in total, 82% of the studied species have a high vulnerability that needs protection. Thematically, geomorphological and tectonic geosites are a total of 67% with high vulnerability. Comparison of recent findings with Fernandez results in 2010 has shown a great deal of similarity in terms of the shape and subject matter of geosites and the level of vulnerability. In general, these complications are scientifically very important due to the specific conditions of their creation and persistence. Also, the existence of these features is aesthetically valuable and can create valuable places to attract tourists, so the management of such environments is essential.
Prosser, C.D. (eds), The History of Geoconservation. Geological Society, London, Special Publications, 300, 31-36.