Albian Foraminifera from Vértessomló Vst-8 borehole, Vértes Mountains (Hungary)

• Main Author: Szinger, Balázs
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2008
• Subjects: Q1 Science (General) / természettudomány általában; Planktonic foraminifera
• Online Access: http://real.mtak.hu/156024/; http://real.mtak.hu/156024/1/03_szinger.pdf

The subject of this research is a rich and well-preserved foraminifera fauna of Albian age from Vértessomló Vst-8 borehole of Vértes Foreland (Transdanubian Range, Hungary). A fifty-meter section of the sequence contains a quantity of this diversified microfauna within the ~100 m thick Vértessomló Siltstone excavated by the borehole. The microfauna is dominated by foraminifera. The samples were dissolved in hydrogene peroxide and concentrated acetic acid. The fauna indicates Albian age but most of the species have wide stratigraphical distribution. Tritaxia, Gavelinella, Favusella are the dominant genera. Determination of 40 taxa, their statistical evaluation and their classification into morphogroups are given. The investigated sequence can be divided into three parts according to the ratio of calcareous/agglutinated forms, planktonic/benthic forms, inbenthic/ epibenthic forms and diversity. The lower part of the sequence was deposited in a weakly dysaerobic off-shore marine environment which contains Orbitolina redeposited from the platform of the Környe Limestone. The middle part of the sequence was formed in a planktonic foraminifera-rich (Hedbergella, Favusella), low energy offshore environment with limited amount of nutrient and low/moderate degree of oxygen depletion (dysaerobic environment). On these results the upper part of the sequence can be described as a formation sedimented in a nutrient-rich dysaerobic (moderate degree of oxygen depletion) environment.