Post-Illirian major-fold subdivision of the transitional area between the Middle and Eastern Balkan Mountains

Pages: 
pp. 41-58
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
Abstract: 

During the Upper Cretaceous, the land concerned in this study was part of an extensive area of monotonous tectofacies evolution involving a spatially uniform, rhythmic (mostly flysch), carbonate-terrigenous and volcanic-terrigenous (there was active volcanism in adjacent areas) sedimentation, the general monotony being broken by events of olistostrome deposition and consedimentation block movements restricted both in space and in time. From the north to the south, the post-Illirian structural pattern has been found to involve parts of the Illirian Luda-Kamčija synclinorium and the contemporaneous Kačulka anticline and Vrailec anticlinorium surrounding it from the south. By either thrust faulting or recumbent folding, the latter's western periclinorium was overlaid by the northeastern margin of the eastern end of the Laramide Srednogorie anticlinorium, the margin manifesting intense polyphase deformation and block fragmenting. The existence of the so-called Kozuina syncline, named after a mountain peak west of the town of Sliven, has not been confirmed in this study. Essential structural differences have been found between the Srednogorie anticlinorium and the adjacent major Illirian folds. In the area studied, there is the largest areal concentration of faults of Tvârdica orientation and Upper Cretaceous tectonic activity indicating that the Tvârdica strike-slip fault set axis active during the Upper Cretaceous geochron to the south of the Balkan Range should be sought there.

VOLUME 21 (1)/February 1991

Geological Institute, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria

Institute of Regional Geology for Latin America (IGREPAL), National University of San Juan (UNSJ), Argentina
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Institute of Regional Geology for Latin America (IGREPAL), National University of San Juan (UNSJ), Argentina
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Institute of Regional Geology for Latin America (IGREPAL), National University of San Juan (UNSJ), Argentina
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Institute of Regional Geology for Latin America (IGREPAL), National University of San Juan (UNSJ), Argentina

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia

Université Claude-Bernard- Lyon 1, Centre des Sciences de Ia Terre et Unité associée au C.N.R.S. no 11, 27-43 Boulevard du 11 Novembre, 69622 Villeurbanne Cedex (France)
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Ecole supérieure des Mines et de Géologie, 1156 Sofia

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria