Центральная Северная Болгария в юрский период

Pages: 
pp. 3-68
Геологический институт „Страшимир Димитров“, БАН, 1113 София
Геологический институт „Страшимир Димитров“, БАН, 1113 София
Геолого-разведочное предприятие „Плевен“, 5800, Плевен
Геолого-разведочное предприятие „Плевен“, 5800, Плевен
Abstract: 

I. Sapunov, P. Tchoumatchenco, A. Atanasov, A. Marinkov. Central North Bulgaria during the Jurassic. During the Early-Middle Jurassic Central North Bulgaria belonged to the Moesian Early-Middle Jurassic Platform. Even as early as the Hettangian it gradually started sinking. As a result of this a marine ingression started over its lowermost grabens. Within limited areas the marine ingression was preceded by continental accumulation of swamp and lake sediments. The link between the marine basin and the Vardar Ocean was the strait along the Tundža Diagonal Early-Middle Jurassic Fault-Angle Valley (=tilt-block basin) which was orientated towards the southeast-northwest. The fault-angle valley demarcated the Thracian Massif in the west·from the West Pontids in the east, which were presented by the Zlatarski Exotic Ridge and by its northern shelf. Between the Zlatarski Ridge in the south and the Moesian Platform in the north lay the Matorian Early-Middle Jurassic Flysch Trough (fig. 20). The Early-Middle Jurassic marine transgression gradually spread all over the Moesian Platform to reach its maximum at the end of Callovian. Thus the detached epicontinental basin became a place of terrigenous and terrigenous-carbonate sedimentation, the depths being within the limits of the shelf, i. e. down to about 200 m.
   From the beginning of Callovian in the marine basin started a stage of bathymetric diferentiation, which was a result of a notable rearrangement of paleotectonic structures. Thus the central part of the homogenous by that time Moesian Early-Middle Jurassic Platform faulted and sank. This led to the differentiation of two independent platforms – the Western Moesian Late Jurassic-Early Cretaceous Carbonate Platform and the Eastern Moesian Late Jurassic-Early Cretaceous Carbonate Platform which were separated by the Central Moesian Late Jurassic-Early Cretaceous Basin. The Niš-Trojan Late Callovian-Valanginian Flysch Trouglt was gradually formed south of them. During the Callovian the Tunža Fault-Angle Valley did not exist any more. As a result of that the Thracian Massif joined the West Pontids and the adjoining Matorids. All these together became a source land to the Niš-Trojan Flysch Trough (fig. 25). By means of this trough the link to the east with the Vardar Ocean was realized. While over the carbonate platforms the environments were very shallow-water (depths of the order of 10-20 m), in the basin, where pelagic limestones deposited, the depths were of the order of 150-300 m. In the lowermost parts of the flysch trough the depths reached the lower part of the epibathyal, i.e. – 500-600 m.

VOLUME 21 (5)/October 1991

Геологический институт „Страшимир Димитров“, БАН, 1113 София
|
Геологический институт „Страшимир Димитров“, БАН, 1113 София
|
Геолого-разведочное предприятие „Плевен“, 5800, Плевен
|
Геолого-разведочное предприятие „Плевен“, 5800, Плевен

Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, 1184 Sofia
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Institute of Meteorology and Hydrology, Bulgarian Academy of Sciences, 1184 Sofia
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University of Mining and Geology, 1156 Sofia

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

Геологический институт, Болгарская акедемия наук, 1113 София
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Геологический институт, Болгарская акедемия наук, 1113 София

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