Why bother about gradients? – a SQUID based full tensor magnetic gradiometer for mineral exploration

The aim of this work is to deploy a new SQUID (Superconducting Quantum interference device) based instrument for the measurement of the full magnetic gradient tensor of the Earth’s magnetic field in survey scenarios in a sedimentary basin in Thuringia, a local province in Germany. This task requires developing according processing, inversion, and interpretation techniques for this new instrument. The recent state of the instrument and data processing techniques is presented. The new instrument has several advantages compared to commercially available high-resolution aeromagnetic survey instruments. Besides the fact that weaker magnetic anomalies could be detected, it delivers vector data and thus more detailed information even on remanence of the geologic structures. It is required for more enhanced magnetic anomaly delineation and possibly for the determination of the age of intrusive or alteration structures. As a proof of principle a small-scaled magnetic anomaly on the border of the Thuringian basin was selected. The area was mapped in 2013. The results are presented and preliminary results of the inversion discussed which indicate remanent magnetization of the rocks which cause the magnetic anomaly.