GNGTS 2017 - 36° Convegno Nazionale

706 GNGTS 2017 S essione 3.3 Field example. TheGalinge iron-ore deposit, located at the centre of Qimantagemetallogenic belt, is one of the important skarn iron deposits in Qinghai province (NW China) (Liu et al. , 2017). The iron orebodies in this deposit are totally covered by the wide and thick quaternary gravels. The magnetic prospecting is one of the most effective approach to explore the magnetite deposits. The contour map of the total field anomaly reveals that there are apparent and regular magnetic anomalies, of which the length and width reach to 1200 m and 500 m showing ellipsoid shape and prolonging NW-SE direction, and whose amplitude exceeds 1500 nT (Fig. 2). M-IDC and M-IDI methods are used to recover the magnetization intensity distributions and to estimate the magnetization direction. The inversion results reveal that there remains two magnetite belts occurring at the north and south of the mining area and striking NW-SE direction (Fig. 3a). The northern one is the main orebody, of which the average top-depth is 200 m and the true thickness is nearly 150 m. And it is inclined to south-west direction with dipping angle 70-80° and extending 250-300 m. The northern orebodies are verified by series of drillholes (Fig. 3a). The drillhole logs reveal that the thickness of Quaternary gravels reach Fig. 1 - Scatter plots of inverted magnetization inclination and declination of synthetic mode using: a) MMM, b) MID, c) M-IDCG, d) M-IDC, and M-IDI methods