The Botevgrad basin: main characteristics and evolution

Pages: 
pp. 47-58
Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
Abstract: 

The Botevgrad basin is one of the numerous Late Pliocene–Quaternary basins developed over the Balkanide orogen. The basin is developed in the West Balkan tectonic zone and on the northern slopes of the Stara Planina Mountain along the Plakalnitsa fault zone, the front of the orogen. The basin was interpreted as half-graben formed on the SW block of the Dragoybalkan fault, considered as the Plakalnitsa fault zone’s extensionally reactivated roots. Our data suggest that the basin formation is more complicated and all basin boards are fault predestined. The boards are morphologically well prominent and their geometry is a result of the reactivated older faults’ segmentation, combined with the different rheology of the basement lithologies, mainly Palaeozoic low-grade metamorphites and intruded into them syn- to post-metamorphic granitoids. The distribution of the numerous depocentres, the orientation of drainage systems, watershed shape and depositional system migration indicate polyphasic basin evolution. The basin shape and other data, such as criteria for sense of shearing, and intrabasinal push-up blocks’ rotation, suggest that the Botevgrad basin should be interpreted as pull-apart basin.

Keywords: 

Pliocene–Quaternary basin system, Botevgrad basin, pull-apart basin

VOLUME 47 (2)/November 2018

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
testing

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
|
Institute of Mineralogy and Crystallography, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 7, 1113 Sofia, Bulgaria
|
Institute of Geochemistry and Petrology, ETH-Zurich, Switzerland
|
Sofia University “St Kliment Ohridski”, Department of Mineralogy, Petrology and Economic Geology, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria

Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
|
Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
|
Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria