Time calibration of sedimentary sections based on insolation cycles using combined cross-correlation: dating the gone Badenian stratotype (Middle Miocene, Paratethys, Vienna Basin, Austria) as an example |
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| Authors: | Johann Hohenegger and Michael Wagreich |
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| Institution: | (1) Department of Palaeontology, University of Vienna, 1090, Vienna, Austria;(2) Department of Geodynamics and Sedimentology, Center for Earth Sciences, University of Vienna, 1090, Vienna, Austria |
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| Abstract: | Cross-correlation between insolation intensities and a combination of sedimentary characters is introduced to obtain precise
time calibration of sedimentary cycles. The first step is to transfer the section scale into ages using power spectra comparing
the main periods with orbital cycles, while in the second step the standardized values of sedimentary signals are cross-correlated
with the standardized insolation curve. As an example for the applicability of the method, we investigated calcium carbonate,
organic carbon in a 9-m sampled section from the historical Badenian stratotype at Baden/Sooss (Lower Austria). Comparing
courses of geochemical parameters between the historical stratotype and a nearby drilled 102-m scientific core resulted in
continuation of the core section into the stratotype. Cross-correlation between magnetic susceptibility (MS) combined with
the negatively correlated calcium carbonate content of the drilled section on the one side and summer solar insolation at
65° northern latitude on the other resulted in an extremely significant correlation between −14.221 and −13.982 Ma. This is
younger than the before estimated time frame (−14.379 to −14.142 Ma) based on cross-correlation between MS and the orbital
100-kyr eccentricity and 41-kyr obliquity cycles. The direct continuation of the drilled section by the stratotype covering
a time span of 17.7 kyr consequently dates the Badenian stratotype between −13.982 and −13.964 Ma. Therefore, the upper limit
of the stratotype, assigned to the Early Badenian, puts it close to the Langhian/Seravallian boundary at −13.82 Ma, demonstrating
the need for revising the Badenian stratigraphic subdivision based on orbital cycles, especially the middle Badenian Wielician
substage. |
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