VLAD ROSCA, SORIN RADAN
Institute of Applied Geophysics, Bucharest
and
SILVIU RADAN
Geological Institute, Bucharest
(Abstract)
In 1969 regional magnetic measurements were made in NW Oltenia in order to
draw up the map of the vertical component of geomagnetic field on the Romanian
territory – scale 1: 200,000. A magnetic anomaly has been rendered evident
in the Matasari-Runcurel area. Initially, the anomaly appeared as a deep-dipole.
The paper also comprises an ordinary attempt, with interesting results, at
a quantitative interpretation of the source. After some detailed measurements,
it proved to be a disturbed field produced by a layer of porcellanites accompanying
a layer of Levantine coal. The X-rays of these porcellanites showed data which
proved that the rock forming temperature exceeded the Curie point of ferromagnetic
minerals. It was possible to define the relatively important remanent magnetization
of the porcellanites as a thermoremanent magnetization.
Finally, it was showed that there exists the danger in the regional magnetic
mapping that such anomalies might be attributed to a deep cause. The importance
of mineralogic and petro-magnetic lab analyses was emphasized for fixing "differential
diagnosis" similar to the above-mentioned and also for the reduction of
the detailed field measurements.