Структурно-тектонические особенности Северо-Западной Болгарии

P. Bokov, A. Vassileva. Structural-teclonic peculiarities of North West Bulgaria. Major regional tectonic units in the territory studied are the Vidin-Strehay Vault and the Lom Depression in the Moesian Platform, and the Severin Belt (Southern Carpathians) which is a part of the Carpathian-Balkan Arc.
   Paleozoic, Triassic, Jurassic-Cret acecus-Paleogene and Neogene-Quaternary structural stages arc distinguished. Their characteristics are illustrated with structural maps and geological cross-sections. For the first time a subdivision of the Paleozoic structural stage is given. Two atectonic processes are established which have disturbed the structural pattern. The first one is connected with sedimentological phenomena in the Upper Jurassic – Lower Cretaceous substage when carbonate constructions formed at the boards of Lom Depression. The second process is an in tense pre-Neogene denudation during the Oligocene and Miocene when a buried relief of amplitude more than 600 m was formed.
   From the bottom to the top of the Phanerozoic sequence there is a clearl y expressed simplification of structural deformations.