GABRIELA POLONIC
Institutul de Geodinamica "Sabba S. Stefanescu" al Academiei Romane,
Bucuresti
EXTENSION – AN ESSENTIAL DYNAMIC PROCESS IN THE FORMATION OF THE TRANSYLVANIAN DEPRESSION
(Abstract)
The paper shows, base don seismic data, hydrocarbon exploration lines and
borehole data, an extensional process which dominated the formation of the
Transylvanian Depression and acted at two distinct levels: at the base of the
post-tectonic cover, in the upper cretaceous deposits, and at the base of the
neogene cover, under the Dej Tuff level.
The mechanism of extension was proved to be, more frequently, the displacement
on high-angle normal faults, which have produced horst and graben structures,
almost each element being dominated by normal faults, grouped in horsts and
grabens of second order.
The amount of extension in the Transylvanian Depression was calculated and
represented by a factor 
=
1.05 at the base of the post-tectonic cover and =
1.03 at the base of the neogene cover.
Key words: extension, normal faults, horst and graben structure, Transylvanian
Depression.