Autori: VASILIEV, I.; DE LEEUW, A.; FILIPESCU, S.; KRIJGSMAN, W.; KUIPER, C.; STOICA, M.; BRICEAG, A.

Editorial: Palaeogeography, Palaeoclimatology, Palaeoecology, 297, p.54–69, 2010.

Rezumat:

Amarked paleoenvironmental change took place at the beginning of the lateMiocene in the Central Paratethys,with dominantly marine Sarmatian successions grading rapidly into mainly brackish Pannonian deposits. A long and excellently exposed section comprising the Sarmatian–Pannonian transition has been investigated at Oarba de Mures in the Transylvanian basin (Romania). In this paper, we focus on both radiometric and magnetostratigraphic dating to provide a chronology for the Sarmatian–Pannonian transition in Transylvania. Two volcaniclastic layers, located approximately 40 mbelowthe Sarmatian–Pannonian transition, yield excellent 40Ar/39Ar ages. The weighted mean plateau age for biotite and sanidine separates provided isotopic ages of 11.62±0.12Ma and 11.65±0.13 Ma. This implies deposition during the magnetic chron C5r.2r, which is in agreement with the magnetostratigraphic results of the Oarba de Mures composite section. Rock magnetic analyses indicate greigite as the main magnetic carrier, with characteristics very similar to the magnetosomal greigite found in the Carpathian foredeep. The newly obtained chronology at Oarba de Mures constrains the age of the Sarmatian–Pannonian transition in the Transylvanianbasin to 11.3±0.1 Ma, slightly younger than the 11.61 Mapostulated in the Styrian andVienna Basins.

Cuvinte cheie: Transylvanian Basin, Sarmatian, Stratigraphy, Miocene