Erik Wolfgring

Changing Investigation Perspectives: Methods and Applications of Computed Tomography on Larger Benthic Foraminifera

The use of computed tomography to investigate the structure of Larger Benthic Foraminifera is presented. Several steps are required to obtain sharp and usable images with MicroCT machines. These steps are explained in detail along with select insights on larger foraminifera. This technique, which delivers three dimensional models, gives the operator the possibility to measure nearly every possible morphometric parameter on either a two- and three-dimensional basis.

Morphological variations in Cycloclypeus carpenteri: Multiple embryos and multiple equatorial layers

In this work, 17 specimens of Cycloclypeus carpenteri have been analysed by means of microCT scanning. It has been observed that many specimens possess multiple embryos, multiple nepionts and some tests show more than one equatorial layer. The diameter of each proloculus has been measured, and it seems that they are very variable even within the same specimen, therefore questioning the long known theory that schizonts have smaller proloculi than gamonts and also questioning the fact that proloculi in the same species should all have comparable size. Whenever the nepionts are positioned on different planes, thus creating an angle between them, this angle has a significant correlation to the angle connecting different equatorial layers. T-shaped connections are located at the junction between two equatorial layers; these junctions are made by a chamberlet, which possesses an unusually higher number of apertures, resembling the chamberlet structure of the genus Spiroclypeus. Antonino Briguglio. Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, Gadong BE1410, Brunei Darussalam, antonino.briguglio@ubd.edu.bn; Shunichi Kinoshita. Department of Palaeontology, University of Vienna, Geocenter, Althanstrasse 14, A1090 Vienna, Austria. shunichi.kinoshita@univie.ac.at Johann Hohenegger. Department of Palaeontology, University of Vienna, Geocenter, Althanstrasse 14, A1090 Vienna, Austria. johann.hohenegger@univie.ac.at Erik Wolfgring. Department of Geodynamics and Sedimentology, University of Vienna, Geocenter, Althanstrasse 14, A-1090 Vienna, Austria. erik.wolfgring@univie.ac.at

A quantitative look on northwestern Tethyan foraminiferal assemblages, Campanian Nierental Formation, Austria.

Deposits spanning the Radotruncana calcarata Taxon Range Zone at the Postalm section, Northern Calcareous Alps (Austria) are examined quantitatively for foraminiferal assemblages, especially the planktonic group. This study focuses on establishing a high resolution record spanning an 800 ka long stratigraphic interval from the active continental margin of the Penninic Ocean. The Postalm section displays reddish limestone- marl alternations representing precession cycles. For this study, 26 samples were taken bed by bed to allow a “per-precession-cycle” resolution (i.e., a minimum sample distance of ∼20 ka). Samples from limestones as well as from marls were examined for foraminiferal assemblages. Data suggest a typical, open marine Campanian foraminiferal community. The >63 µm fraction is dominated by opportunist taxa, i.e., members of Muricohedbergella and biserial planktic foraminifera. Archaeoglobigerina and “Globigerinelloides” appear frequently and benthic foraminifera are very sparsely found. The share of globotruncanids, representing more complex morphotypes amongst planktonic foraminifera, is recorded with 5–10%. The state of preservation of foraminifera from the Postalm section is moderate to poor. Differences between samples from marls and samples from limestone are evident, but do not reveal evidence that there was an influence on the postdepositional microfossil communities. However, data from microfossils showing moderate to bad preservation can still offer valuable insight into the palaeoenvironment and biostratigraphy. Information gathered on the composition of the planktonic foraminiferal assemblage confirms a low-to-mid-latitude setting for the Postalm section. As well resolved records of Late Cretaceous foraminifera assemblages are rare, the examination of the Radotruncana calcarata Taxon Range Zone provides some insights into variations and short term changes during the very short period of 800 ka.