CRISAN DEMETRESCU, GABRIELA POLONIC
Centrul de Fizica Pamantului, Bucuresti-Magurele, Romania
(ABSTRACT)
The geological and thermal evolution of the Romanian sector of the Pannonian
Depression is discussed, based on borehole data on the thickness of various
sedimentary formations and on heat flow data.
In the reconstruction of the geographical and time distribution of the subsidence
and heat flow a backstripping technique which allowed for decompaction was
used, based on the depth distribution of rock density to the depth of 3500
m. The time evolution of the tectonic subsidence and heat flow was derived
for 75 boreholes, which enabled the extension of Pannonian lithosphere to be
calculated and some conclusions on the thermo-mechanical phenomenon leading
to the formation of the Pannonian basin to be drawn.
Borehole, heat flow, and crustal structure data might be explained by the homogeneous
extension of the lithosphere of 0 – 40 per cent, at a Badenian or pre-Badenian
moment, followed by the conductive decay of the thermal anomaly induced by
extension. The additional heat, of convective origin, in the lithosphere after
extension is estimated at 15 – 30 mWm-2 for the study area.
Key words: Pannonian Depression, lithospheric extension, subsidence, heat flow.