Spatial variability within a single parautochthonous paratethyan tidal flat deposit (Karpatian, Lower Miocene - Kleinebersdorf, Lower Austria)

Author(s)
Martin Zuschin, Mathias Harzhauser, Oleg Mandic
Abstract

Six samples from a single shell bed in two adjacent outcrops were studied at Kleinebersdorf (Lower Austria) to identify outcrop-scale variability in faunal composition, the nature of shell bed formation and the original environment of the molluscan fauna. Thirty-five taxa (32 species) were identified from 1581 individuals. A diversity analysis shows that the full range of species in the shell bed was not covered, but higher sampling intensity would only add more rare species without changing the rank order of the most abundant and middle ranked taxa. Diversity, estimated from the steepness ofthe species-individual curves and measured as heterogeneity diversity, differed consistently between the two outcrops. Patchiness in quantitative molluscan composition was best indicated by differences in the rank order of the most abundant species, but differences between outcrops were not statistically significant. The concentration process most likely responsible for the shell bed formation is gentle winnowing by currents, which were not strong enough to significantly transport or orient the shells. The rather low total diversity of this parautochthonous to slightly transported molluscan assemblage points to a physically controlled original environment. The cooccurrence of the most abundant bivalve species Loripes dentatus, Dosinia lupinus and Diplodonta rotundata points to a low-energy coastal setting with at least partly nutrient-rich sediment within the older intertidal and/or upper subtidal, for example a sheltered embayment or semi-enclosed lagoon. The most abundant gastropod species, the batillariid Granulolabium plicatum, supports the interpretation of a parautochthonous to slightly transported tidal flat deposit.

Organisation(s)
Department of Palaeontology
External organisation(s)
Naturhistorisches Museum Wien (NHM)
Journal
Courier Forschungsinstitut Senckenberg : CFS
Pages
153-168
No. of pages
16
ISSN
0341-4116
Publication date
2004
Peer reviewed
Yes
Austrian Fields of Science 2012
105118 Palaeontology
Portal url
https://ucrisportal.univie.ac.at/en/publications/73cd5ea2-cdc8-4fdc-bd9a-c162b1eb9aa1