The correlation of high-resolution water seismic profiles measured at Lake Balaton and Pannonian strata in outcrops and boreholes around the lake has been the subject of research for nearly 30 years. The first attempt to find a correlation was presented by SACCHI et al (1998, 1999). They suggested that the silicified carbonate cones (i.e. the “geyserites” mentioned by LÓCZY 1913) exposed in the Tihany peninsula could be associated with characteristic high-amplitude mounded features identified on seismic profiles. These mounds are situated at the top of a seismic unconformity, formerly interpreted as a sequence boundary (Pan–2). To test this correlation a drilling was performed in the eastern basin of Lake Balaton in order to collect samples from one of the mounds and the underlying beds. Core samples showed lithological features similar to the Fehérpart section of the Tihany Member — i. e. clays and siltstone — but no silicified carbonates were found. Based on their seismic geometry, this paper interprets the mounds as slumps that formed in the prodelta of progradational delta lobes deposited between 8.4–8.7 Ma in the Lymnocardium decorum biochron. Gamma-intensity and susceptibility measurements combined with observed lithological features and seismic data also revealed the bottom of these slumps. This bottom is characterized by mollusc shell fragments and centimetre-scale, soft-sedimentary deformations. The drill penetrated the Pan–2 horizon, which turned out to be a sharp boundary between clayey and sandy sediments. Be-isotope ages and reverse magnetic polarity of the core suggest that the formation of this horizon occurred during the C4Ar (9.1–9.8 Ma) chron. Thus it appears to be much older than 7.9 Ma, as was earlier suggested by HORVÁTH et al. (2010).
|Translated title of the contribution||Results of the TFM–1/13 exploration borehole sampling of pannonian strata below lake balaton|
|Number of pages||14|
|Publication status||Published - Jan 1 2017|
ASJC Scopus subject areas
- Geochemistry and Petrology