High-frequency cyclicity in a Miocene sequence of the Vienna Basin established from high-resolution logs and robust chronostratigraphic tuning

Abstract

A high-resolution chronostratigraphic record established by [W.E. Paulissen, S.M. Luthi, P. Grunert, S. Ćorić, M. Harzhauser, Geol. Carp. (2011)] that takes into account variations in sedimentation rates and temporal gaps caused by unconformities and faulting in a research borehole in the Vienna Basin was used to investigate the possible presence of orbital, millennial and centennial periodicities. The sedimentary sequence covers Middle to Late Miocene shallow marine, fluvio-deltaic and lacustrine shales, silt- and sandstones deposited during the transition from a pull-apart basin to the final infill in a compressional regime. Spectral analysis was performed on gamma ray logs and high-resolution electrical borehole images using three different analytical methods over six suitable intervals where continuous and constant sedimentation was identified. The significant periods were found to closely match the orbital cycles of precession, obliquity and short eccentricity, providing a solid basis for the analysis of potential sub-Milankovitch cycles. The significant frequencies encountered at the millennial- to centennial-scale fell for 75% within a relatively narrow time period of 0.25 to 5 kyr, with a concentration of peaks between 1 and 2 kyr (29%) and 500 to 800 years (17%). These periodicities relate closely to the millennial- (Dansgaard–Oeschger and Bond cycles) and centennial-scale climate cycles documented from the Quaternary. It is suggested that the high-frequency cycles observed in the Miocene of the Vienna Basin represent differences in grain size related to cyclic variations in regional precipitation.