کارشناسارشد مهندسی اکتشاف معدن، دانشگاه صنعتی شاهرود، شرکت سیمان قاین
عنوان مقاله [English]
According to this reality that iron bulks because of having ferromagnetic minerals, they have high magnetic intensity, in mining explorations most usual geophysical method suggested to explore these resources is magnetic method. Basically in order to process and interpretation of magnetic anomaly maps several methods be used of which most of these methods are based on try and error. One of usual geophysical data refining or filtration methods is upward continuation which will be applied in this study. Upward continuation can be used to separate a regional and local magnetic anomaly from the observed magnetic. One of problems that we encounter it through this filtration is determining optimum height of upward continuation. We use a practical method to derive an optimum height for upward continuation. In this study magnetic data of northern anomaly of Mansoorabad region of Yazd was investigated. According to past studies in order to handle geophysical investigations for carry out magnetic investigation a region of 450x700 square meters were adapted. Data acquisitions of magnetic data in exploration grid were done via 10 meter distance for both profiles and measuring stations. Outcrops of iron in the form of hematite in Ooliti'c's limestone rocks are evident. In order to separation of regional anomaly the usual upward continuation were used firstly. Using this method a map of 35 meter height were detected as regional anomaly. In the following in order to more accurate interpertation and process and also determination of height of upward continuation filter, one of practical methods of which is based on cross correlation of two successive heights were used. With the aid of this method without any comparison of several maps related to various heights and without any interference of a body one can obtain suitable upward continuation filter to determine regional magnetic anomaly and consequently by subtracting this magnitudes from observed overall anomaly one can estimate map of remained anomaly that could be a better evident of local anomaly in that region. Cross correlation for upward continuation of heights from 30 meters to 40 meters by the distance of 2 meters were calculated in which the height of 39 meters were selected as optimum height of investigated data. The map of upward continuation which was calculated by this height for magnetic data of Mansoorabad region showed the best fitting with regional anomaly of data based on used method. Also the map of remained data will be obtained according to this height. In terms of geology mineralization of iron that was formed in this region is sedimentary iron type of Oolitic which were created in the time limit of Paleozoic age. Considering location of determined anomaly and geology map of region, observed that this kind of mineralization of iron in limestones by the pattern of Oolitic were created. After investigation and coincidence of magnetic anomaly in studying area, it is determined that the iron bulks were the reason of anomaly. Depth continuations of this kind of anomalies are different and are continued to the depth of 80 meters.