Thematic Set: Integrating magnetostratigraphy, biostratigraphy, cyclostratigraphy and seismic data to obtain a high resolution stratigraphic record: a case study from the Vienna Basin

Abstract

We have developed an integrated methodology to obtain a high resolution stratigraphic record that assists in evaluating the relative contributions of tectonics, eustacy, and other factors to sedimentary basin infills. The approach combines magnetostratigraphic and biostratigraphic analyses of well data to form a basic chronostratigraphic framework. Seismic data are included to refine the time lines by taking into account unconformities and faults that cause time gaps. These are subsequently corroborated by detailed analysis of electrical borehole images. The latter, having a vertical resolution of about 1 cm, are used to perform a spectral frequency analysis in order to identify cyclicities in the sedimentary record. Using the chronostratigraphic framework, the cyclostratigraphic analysis is well constrained and can provide a temporal resolution that lies significantly higher than the Milankovitch cycles. This methodology is demonstrated with a dataset from a borehole in the Central Paratethyan Vienna Basin. Focusing on the Upper Sarmatian, the approach described above resulted in accurate chronostratigraphic age dating, the identification and location of time gaps caused by unconformities and faults, and an accurate sedimentation rate for this stage. The cyclostratigraphic results indicate that a strong allocyclic orbital forcing was superposed on the overall tectonic evolution of the basin.