عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Kharket Polje is one of the most outstanding Karstic feature in Khorasan-Razavi province which is located 55 Km to the north of Mashahd. This polje is covered by Mozduran carbonate Formation and marginally by Shoorije Formation in the north and quaternary sediments in the center. During this survey, 33 samples including 28 samples from Mozduran carbonates and 5 samples from quaternary sediments were collected and the concentration of Sr, Mg, Mn, Fe and Ca were analyzed. The distribution map of these elements in the study area and factor analysis depicted the parameters which control the geochemistry of the polje and identify the locations of high concentration of the elements. Increase in Fe and Mn concentration in the carbonate samples is due to influence of diagenetic processes in relatively anoxic to low oxygen environments, whereas increase in these elements values and decrease in Sr concentration in the study samples can be related to their partition coefficient and low concentration of these element in diagenetic fluids. The results of this survey show that Meteoric diagenesis is the most significant factor which controls the geochemistry of Kharket polje whereas the distribution map and factor analysis demonstrates that the concentration of Fe increases dramatically in the base of polje and reaches about 7500 ppm where the slope is considerably lower compare to other parts of polje. The gentle slope of Kharket polje and its lithology (mainly consists of sandstone) in southern parts makes it good geochemical trap for some minor elements such as Fe, Ni and Mn.