Lithosphere and Evolution of the Pannonian Basin: Chapter 12

The Pannonian basin is an area of late Tertiary subsidence. Geophysical features such as an updoming of the mantle, a thinned lower crust, and a strong geothermal anomaly are all restricted to the basin within its geologic boundaries. Three theories are offered for the formation of the basin: (1) a gabbro-eclogite phase transition, (2) lithospheric or (3) mantle diapirism. The first theory suffers serious problems in a heated environment; the second may have contributed a certain amount to the subsidence process with a possible stretching of 10-40%; the third suggestion seems to play the most important role for the geologic development of the basin, related most probably to a back-arc situation in connection with subduction processes in the Carpathian arc. It is shown that a modification of lithospheric such as a differential stretching, and diapirism must be intimately related to each other and both are consequences of an extensional environment.