Modeling and inversion of airborne full tensor magnetic gradiometry data in the Thuringian basin and forest
The recent development of airborne full tensor magnetic gradiometer (FTMG) systems, based on superconducting quantum interference devices (SQUID), allows to obtain the full magnetic gradient tensor of the Earth's magnetic field of large areas (10x10 km). This system allows acquiring all components of the magnetic gradient tensor. This tensor exhibits some advantages over conventional airborne magnetic field data, e.g. a higher spatial resolution and additional directional sensitivity. In this work a FTMG system was applied in the framework of the multidisciplinary INFLUINS project (Integrated fluid dynamics in sedimentary basins) in order investigate different areas in the Thuringian Basin and the neighboring highlands. Main goal was to map magnetic lineaments along major fault zones and to demonstrate the advantages of airborne FTMG. Full tensor data sets have been acquired with very low system noise of only 60 (pT/m). Two different case studies are presented: In the first case study a strong magnetic anomaly in the center of the Thuringian Forest, caused by the magmatic intrusion of the Höhenberger dolerite is analyzed, which exhibits indications of a significant remanent magnetization. Multiple magnetization vector inversions were performed using either the full magnetic gradient tensor or only the total field anomaly data. The inversion results are evaluated using magnetization directions acquired by paleomagnetic sampling and available geological information. In the second case study, a small magnetic anomaly was investigated. It was discovered while mapping magnetic anomalies along the Eichenberg-Gotha-Saalfeld fault zone, which is one of the major fault zones in the Thuringian Basin. The detected lineament is interpreted using the components of the magnetic gradient tensor, additional ground based geo-electrical data and available geological information. The inversion of the magnetic gradients revealed a steeply dipping zone of mostly induced magnetization.
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