Airborne vector magnetics mapping of remanently magnetised banded iron-formations at Rocklea, Western Australia

Abstract

Strongly remanent magnetic sources such as those found in the banded iron-formations (BIFs) of the Hamersley Basin impair the interpretation of standard total magnetic intensity survey data. The use of aircraft attitude information, provided by the FALCONTM airborne gravity gradiometer (AGG) system, makes it possible to reference geographically the vector magnetic information collected by the fluxgate triad on board the aircraft. A full aircraft compensation processing method, allowing for permanent, induced and eddy current effects, provides usable vector magnetic data. These data supply valuable extra information for the interpretation of strongly remanent BIFs. An example using data from a FALCONTM survey near the Rocklea Dome in the Hamersley Basin demonstrates improved mapping of the BIFs by the use of the vector-residual magnetic intensity data.