Aeromagnetic survey data obtained in offshore eastern Canada

1975 ◽  
Author(s):  
P J Hood ◽  
M Bower
Keyword(s):  
Survey Data ◽  
Eastern Canada ◽  
Aeromagnetic Survey

scholarly journals Detailed airborne geophysical survey of complexly dislocated strata in the Sutam terrane (Aldan shield) during studies of iron-ore deposits

2020 ◽  
Vol 11 (1) ◽  
pp. 141-150 ◽  
Author(s):  
A. A. Syasko ◽  
N. N. Grib ◽  
V. S. Imaev ◽  
L. P. Imaeva ◽  
I. I. Kolodeznikov
Keyword(s):  
Magnetic Field ◽  
Experimental Study ◽  
Survey Data ◽  
Iron Ore ◽  
Ore Deposits ◽  
Aeromagnetic Survey ◽  
Geophysical Surveys ◽  
Iron Ore Deposits ◽  
And Control ◽  
The Magnetic Field

Magnetic exploration is the most informational and economical method of prospecting and exploration of iron-ore deposits. In rough-terrain and remote areas without any infrastructure, problems associated with ground-based methods can be avoided by using modern unmanned technologies that allow conducting geophysical surveys in a more efficient way. An unmanned aeromagnetic survey complex (aerial vehicle, UAV) Geoscan 401 was used to assess the possibility of using UAVs for aeromagnetic surveying of iron-ore deposits. Our experimental study was conducted in the well-studied area of the largest iron-ore deposit of South Yakutia. The UAV capacities were confirmed by comparing the aeromagnetic survey data with the available data obtained by ground magnetic exploration of the study area. By analysing magnetic fields, we established that the anomalies detected by the ground and aeromagnetic surveys were fully identical. Furthermore, a weak anomaly was discovered in the northeastern part of the study area (it was not reflected in the magnetic field from the ground survey data). Recalculation of the vertical gradient of the magnetic field shows that the anomaly is caused by a blind ore body. Its upper edge is located at a depth of 200–250 m from the day surface. In calculations for a data array without gradient intervals, a mean square error (MSE) amounts to 1.01 nT. An absolute error in the heights of the working and control flights did not exceed 1.5 m. Both the preliminary and control measurements were performed very efficiently. Profiles for UAV surveys were spaced by 100 m. A 1.0 km2 site was covered by one flight within approximately 20 minutes. The Geoskan-401 UAV is useful for obtaining orthophotos, topographic maps and 3D models of the surveyed territory as required for further studies consistent with the magnetic surveys. The aeromagnetic surveys were followed by trenching to verify the newly discovered anomalies. Based on the results of this experimental study, the forecast resources of the Sutam deposit should be increased by almost 250–350 million tons, i.e. plus 15 % to the previously explored and approved reserves of the Sutam field.

Werner deconvolution for variable altitude aeromagnetic data

Geophysics ◽  
1993 ◽  
Vol 58 (10) ◽  
pp. 1481-1490 ◽  
Author(s):  
Julius S. Ostrowski ◽  
Mark Pilkington ◽  
Dennis J. Teskey
Keyword(s):  
British Columbia ◽  
Linear Function ◽  
Survey Data ◽  
Horizontal Position ◽  
Numerical Instability ◽  
Aeromagnetic Data ◽  
Deconvolution Method ◽  
Aeromagnetic Survey ◽  
Flight Height ◽  
Subsequent Selection

The standard Werner deconvolution method is extended to include the effects of variable sensor altitude but this leads to a deconvolution algorithm that is unstable for slowly changing flight height. By expressing the sensor altitude as a linear function of horizontal position (within a specified window), we show that the numerical instability can be avoided. The subsequent selection and averaging of the raw solutions is controlled by three parameters that can be adjusted to specific survey data characteristics. Results for an aeromagnetic survey over Vancouver Island, British Columbia show that, in comparison with the variable altitude approach, the standard Werner method produces unacceptable errors when applied to variable altitude data.

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