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Berriasian bio- and magnetostratigraphy and magnetic susceptibility of the Barlya section (Western Balkan Unit, Bulgaria) – preliminary results

Grabowski J., Lakova I., Schnabl P., Sobień K., Petrova S.

Volumina Jurassica

2014

Vol. 12, no. 1

185--194

Integrated bio- and magnetostratigraphic data from the Lower to Upper Berriasian of the pelagic succession at Barlya (Western Balkan, Bulgaria) are presented. The investigated interval, 24 m thick, covers the top of the Calpionella elliptica, Calpionellopsis simplex and Calpionellopsis oblonga subzones. Magnetozones from the upper part of M17r up to M16n were identified. The boundary between the Elliptica and Simplex subzones correlates with the lower part of M16r, while the boundary between the Simplex and Oblonga subzones is situated in the lower part of M16n. The magnetic susceptibility reveals an increasing trend from the middle part of M16r which accounts for the increasing supply of fine clastic sediments to the basin.

Palaeomagnetic age constraints on folding and faulting events in Devonian carbonates of the Kielce Fold Zone (southern Holy Cross Mountains, Central Poland)

Szaniawski R., Konon A., Grabowski J., Schnabl P.

Geological Quarterly

2011

Vol. 55, No. 3

223-234

The results of numerous palaeomagnetic studies performed in the last three decades in Devonian carbonates of the Holy Cross Mountains (HCM) have documented the occurrence of several episodes of remagnetisation. This knowledge was applied in this study to determine the temporal relationships between the acquisition of particular secondary palaeomagnetic components and the formation of tectonic structures. This made it possible to estimate the timing of several episodes in the multistage tectonic evolution of particular folds and faults. We show that the westernmost part of the southern HCM was rotated clockwise after the early Permian. Detailed palaeomagnetic analysis documented also shape modifications in some map-scale and minor folds. This tectonic overprinting of originally Carboniferous folds postdated the early Permian. It was furthermore shown that the N-S trending dextral strike-slip faults studied were active between the early Permian and the Permo/Triassic. Our recent data show also the post-early Permian age of breccia that covers the deformed Devonian strata.