عنوان مقاله [English]
order of The rate of corrosion The erosion of karstic dissolution is the amount of corrosivity that occurs in carbonate rock and may occur at the level or in deep sections of the karstic mass (inside the gaps) . Karstic erosion is one of the major issues in hydrogeomorphology, which evaluates the degree of dissolution of carbonate formations on the surface of the interfaces. The purpose of this study is to calculate the rate of erosion karsticity using field and laboratory methods to obtain the results of this research in environmental planning .
In this research topographic maps of 1: 50000 basins were used and 1: 100000 maps of geology were used. We then digitized using the ARC GIS software and prepared layers and maps. The method used in this research is Empirical and laboratory. After field studies and sampling of karst and rivers, we are preparing the required data to estimate the dissolution and erosion of karsticity in the experimental models of Swinging, Corbel, Xiong And also laboratory techniques such as water hardness analysis (TDS), isometry (EC), rock density, calcic acid analysis using ICP method and Bernard calcium in the studied basin. Also, using the weighting methods for lime percentage and also the method of studying the Co2 content, the amount of gas produced was obtained.The study area is Kalat mountain basin in Kopet Dagh Zone, located in the mountaind of the Hezar masjed and northeastern parts of the country
Results and discussion
Empirical techniques and formulas to calculate the Karst erosion rate in the studied basin:
1. Corbel equation
One of the most suitable equations for determining the rate of erosion dissolution is the Corbel Equation, which is presented as follows:
X = 4ET / 100 = 4 × ./7 × 845/100 = 23.66
2. Sweeting equation
Various calculations have been made to determine the level of lowering the level of karst through dissolution. These calculations, without considering the deep dissolution and the presence of organic acids (that is, according to Dalton's artistic law on gas adsorption), is one of the most commonly used ones (Chorley, 2007, p. 215). (Swinging, 1972):
3. Xiong equation
Gyeong et al. (1482: 2009) presented the equations for the Karst dissolution in nature, introduced by Cao (101: 2005). In which the average annual temperature is 16.49%, the erosion rate is 20 cubic meters per square meter. According to their findings, when the air temperature is low, rainfall variations have little effect on the rate of dissolution, but when the temperature reaches 16 to 20 ° C, with the increase in precipitation, the rate of dissolution of the karst increases rapidly. Gyeong equation 4. 20 × 168.37 = 20
The results of the Gyeong model show that in the studied basin, this model is not relatively efficient.
laboratory techniques and formulas to calculate the Karst erosion rate in the studied basin:
1.Measurement of lime in sediment by calcicometric (volumetric) method with Bernard calcium Calcite calcite percentage was determined in calcium test based on the following equation (Zanganeh Asadi, 41: 1395).
1.K = V * 100 / N * 224 .
The average amount of lime purity and calcite content calculated from the samples of the four formations tested was 36.3%.
2.ICP method (analytical inductive coupled plasma):
The results of ICP calcification technique showed that among the four formations investigated, ICP Tirgan, Mozduran, Shurijeh and Sarcheshmeh were Tirgan with 38.43% calcium, Mozduran 2 with 38.43%, Sarcheshmeh with 38.38% and Shurijeh with 7% had the highest lime content in the basin, respectively .
3. Water hardness and density of rock basin
To determine the degree of difficulty of the water sample of the basin, the following relationship is used:
TDS = 0.64 * EC = 0.64 × 1320 = 844.8
To determine the density of the limestone sample, we measured the volume and weight of the sample with a precision laboratory scale, which was 35.18 grams and 22 cubic centimeters, and a density of 1.60 grams per cubic meter.
4. Measure the amount of co2 in the rock
According to the measurements of the amount of co2 in stone samples using a Bernard calcium device, the amount of carbon dioxide or carbon dioxide in the rock samples is 448 cubic centimeters.
5. Weighing test method
According to this experiment in Kalat Formation in sedimentology laboratory, the amount of lime is 56.3%.
To conduct hydrochemical and geochemical experiments, water samples from the surface of the basin were tested for hardness and electrical conductivity. In order to conduct geochemical experiments in basin rocks, 4 rock samples were selected from calcareous formations of the basin including Tirgan, Mozdaran 2, Kalat and Shurijeh. Geological map was marked. In order to achieve our goals, we performed 4 rock samples in Mashhad Azad University Azad University, using ICP, calcium, weighing methods and Co2 measurement method, which average, 38.5, 36.3, 56.3 and 448, respectively The cubic centimeters were obtained with the mathematical and experimental formulas of the corbel, switching and Xiong, the annual dissolution rate of limestone formations of the basin was obtained that With the mathematical and experimental formulas of the Corbel, Swinging and Xiong, the annual formation dissolution rate of the basin was estimated to be 23.66, 12.92 and 20 cubic meters per square meter, which seems Corbel method to be more effective in the studied area.
Key words: Karstic erosion, Sweeting model, Corbel model, Xiong model, ICP method, laboratory techniques