M. Socolescu, D. Popovici and M. Visarion
Abstract
The form of the Mohorovicic surface in the Eastern Carpathians and in the Transylvanian
basin has been computed, as a first assumption (plate 2), with the aid of
the map of the regional isostatic anomaly (plate 1). In order to ensure the
checking, the calculus was also performed by two methods suggested by Soviet
scientists on the basis of seismologic data (plates 3 and 4); it has been
found that the average of the results obtained by these two methods (plate
5) is nearly identical with the initial result, obtained only with the aid
of considerations regarding the isostatic equilibrium.
The presence of a complex fracture in the basement along the Eastern Carpathians
has been deduced with the aid of three characteristic geological sections (plate
6) studied concurrently with the section of the M surface.
The M surface is arched under the Transylvanian basin, where the intermediate
layer (basaltic) seems to rise up to only 12 km from the surface. There can
be noticed a northern zone, with an evident periclinal slope, and a southern
poorly tilted zone, as a result of the presence effected by the Eastern Carpathians.
Under the Eastern Carpathians and in their outer zones, the M surface seems
to have the structure of an accordion, which has probably been produced by
the existence of a recent stress, with a general N–S trend.
The results which were obtained raise new problems in connections with the
distortion of the crust, with its evolution and even with the origin of the
magmatism and of some useful mineral substances.