Geologia Croatica, Vol. 60 No. 2, 2007.
Izvorni znanstveni članak
takPalaeomagnetic Results from the Sarmatian/Pannonian Boundary in North-Eastern Croatia (Vranović Section, Našice Quarry)
Iuliana Vasiliev
; Palaeomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, NL-3584 CD Utrecht, The Netherlands
Koraljka Bakrač
; Croatian Geological Survey
Marijan Kovačić
; Department of Geology, Faculty of Science, University of Zagreb, Horvatovac bb, HR-10000 Zagreb, Croatia
Hayfaa Abdul Aziz
; Palaeomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, NL-3584 CD Utrecht, The Netherlands
Wout Krijgsman
; Palaeomagnetic Laboratory ‘Fort Hoofddijk’, Utrecht University, Budapestlaan 17, NL-3584 CD Utrecht, The Netherlands
Sažetak
The Sarmatian/Pannonian boundary in the Central Paratethys basin is marked by a major regressive event, which isolated the basin from the open sea and resulted in a palaeoenvironmental change from restricted marine to brackish water ecosystems. The exact age of this environmental change is still ambiguous since direct age control on the boundary interval is lacking, mainly due to the scarcity of suitable
sections. The Vranović section in the Našice Quarry in Croatia, however, is relatively long and continuously exposed. A detailed sedimentological
and biostratigraphic study indicates that it contains the Sarmatian/Pannonian boundary and that it reflects the same palaeoenvironmental
trend as other Paratethyan sequences. Here, we present palaeomagnetic and rock magnetic results from the Vranović section, based on 183 sampled levels distributed along 55 m of cyclically bedded limestones and marls. Rock magnetic data indicate the presence of maghemite or haematite in the Sarmatian deposits and low contents of magnetite in the Pannonian rocks. Thermal demagnetization results indicate dominantly normal polarities, and the mean direction closely coincides with the present-day field direction at Našice. We conclude that magnetostratigraphic age control cannot be derived for the Vranović section because of a dominant secondary (post-tilt) magnetization. Consequently, a firm numerical age based on magnetostratigraphy cannot be assigned to Sarmatian/Pannonian boundary events from this section.
Ključne riječi
Palaeomagnetism; Palynology; Sarmatian; Pannonian; Central Paratethys; Croatia
Hrčak ID:
22013
URI
Datum izdavanja:
28.12.2007.
Posjeta: 1.199 *