Comparative depth estimation of iron-ore deposit using the Data-Coordinate Interpolation Technique for airborne and ground magnetic survey variation

Abstract

A newly developed quantitative method, Data-Coordinate Interpolation Technique (DCIT) was used by matching the secondary and primary data to correct the variation that exists between airborne and ground magnetic depth-to-basement. The aeromagnetic data within latitude (8.00⁰N, 8.50⁰N) and longitude (4.00⁰E, 4.50⁰E) were acquired and gridded, while the in-situ location are Ajase (8.1952⁰, 8.1972⁰ N), (4.3880⁰ E, 4.3900⁰ E) and Gbede (8.2920⁰ N, 8.2936⁰ N), (4.3462⁰ E, 4.3476⁰ E). Aeromagnetic data were contoured at airborne to ground spacing ratio and data interpolation was done on the contour to produce a set of interpolated data. Quantitative analysis was done using Peter’s Half slope Method (PHSM), Analytic Signal Method (ASM) and Euler Deconvolution Method (EDM) to calculate the depth-to-top of the iron-ore within the basement complex. Results at Ajase for depth for DCIT and ground data were 6.47 ± 2.28 m, 5.79 ± 1.81 m; 5.55 ± 2.90 m, 5.53 ± 1.90 m; and 7.88 ± 1.52 m, 8.75 ± 1.47 m, respectively. At Gbede, the results were 6.16 ± 2.09 m, 5.34 ± 1.50 m; 5.79 ± 2.07 m, 5.66 ± 1.75 m; and 5.95 ± 1.59 m, 5.74 ± 0.88 m, respectively. The average depths at Gbede with respect to DCIT and ground data were 5.97 ± 1.92 m, 5.58 ± 1.38 m and Ajase, 6.63 ± 2.23 m and 6.69 ± 1.73 m, respectively. Comparatively, the variation in the depth estimates for both airborne and ground magnetic data is minimal with DCIT.

Keywords:

• aeromagnetic data
• iron-ore
• half-slope
• analytic signal
• convolution