Stratigraphy, paleoecology, and paleogeography of the 'Congeria ungulacaprae beds'
(Lymnocardium ponticum Zone) in NW Hungary: Study of the Daka outcrop
The littoral 'Congeria ungulacaprae beds' (=Lymnocardium ponticum Zone) of the Late
Miocene Lake Pannon are widely exposed around the Transdanubian Central Range of NW
Hungary, especially on its NW side. Study of the mollusk fauna of the Daka outcrop,
located near the classic locality of Kup, showed that the fauna of this zone represents
a transitional stage between the older L. conjungens Zone and the younger L. decorum
Zone. The characteristic mollusk association of the L. ponticum Zone is apparently
missing from the stratigraphic record of the southern part of the Pannonian basin.
This difference can be partly explained by the paleogeographical situation. The northwestern
part of the basin, where the Daka fauna lived, was site of rapid delta progradation,
whereas the southern shoreline lacked significant sediment input. However, the littoral,
well-aerated, vegetation-rich environment represented by the Daka layers must have
had its counterpart in the southern part of the basin, where its sediments were either
eroded or lie covered by younger sediments in a more basinward position. The age of
the Daka fauna and of the whole L. ponticum Zone is estimated between 9 and 10 Ma,
on the basis of its correlation to magnetic polarity chron 4Ar in boreholes Berhida-3,
Nagylozs-1, and Duka-II.