Geophysikalische Prospektion im Raum der heimgesagten Sideritlagerstätte am Hüttenberger Erzberg
Research output: Thesis › Master's Thesis
The geomagnetic prospection of mineral deposits like the Hüttenberg-type requires a complex methodology including petrophysical, geological, geochemical and petrological information beside the detailed geomagnetic survey. In the forefront of the detailed studies the area around the Hüttenberger Erzberg was mapped and oriented samples were taken all over the prospecting area. Laboratory investigations were done on oriented cores, thin sections and polished sections, as well as powder fractions, which were used for AAS-Spectroscopy and Curie-points determinations. Measurements and analysis of anisotropy of susceptibility, isothermal remanent magnetization, and thermal- and altering field demagnetization of limonites, marbles and mica schists helped to identify the magnetic carrier minerals and to check for the influence of the remanent magnetization on the magnetic survey. The magnetic carrier minerals were identified as goethite/lepidocrocite, magnetite and hematite. Concentrations and distribution depend on the lithology. Goethite and hematite are dominant in limonitic ore, whereas magnetite and hematite dominate in marbles and schists, although the paramagnetic contribution in the accompanying lithologies is significant. The influence of remanent magnetization could be excluded in respect to an overall Q-Factor <1. Continuous mapping in the “walkmag mode” yielded a set of 63700 measurements in 9 profiles heading north-south over about 7km. The subsequent detailed mapping in descrete mode consists of 2400 measurements in 16 profiles over about 1,5km in the area of the Hüttenberger Erzberg. Daily variations of the earth magnetic field were reduced through the data of a local base station. In addition to that, the data were smoothened, filtered and transformed. A north-south trend was reduced and a reduction to the pole was applied. Anomalies in the range of 250nT were observed in ore bearing areas. The results are presented in profile plots and isoanomaly-maps. Modeling of the geomagnetic data involving all acquired laboratory results and the literature studies has shown that geomagnetic mapping of limonitic ore bodies in this area is possible despite low magnetic contrasts, provided the overburden does not exceed 200 meters. In addition to that, significant differences between geological and archaeological signals were observed.
|Translated title of the contribution||Geomagnetic prospection in the area of the abandoned siderite-deposite of Hüttenberg|
|Award date||17 Dec 2010|
|Publication status||Published - 2010|