Poster Number 146
See more from this Division: Topical Sessions
See more from this Session: The Astronomically Forced Sedimentary Record: From Geologic Time Scales to Lunar-Tidal History (Posters)
Abstract:
Compilation of a continuous record of Cretaceous orbital rhythms was accomplished by time series analysis of rhythmically bedded marine strata from localities across the globe, and stitched together by global chronostratigraphic datums. Multiple high-resolution geochemical and petrophysical time series were constructed from outcrops and cored sections, and from DSDP/ODP cores and boreholes. The most useful measurements were CaCO3, TOC, and well log data (FMS/FMI, gamma ray, magnetic susceptibility, photolog scans). Time series from each locality were analyzed at the stage level, and evaluated for stratigraphic completeness, biostratigraphic and magnetostratigraphic constraints.
Some of the challenges encountered in the study included the presence of major unconformities (e.g., Campanian and upper Turonian), condensed sections resulting in stratigraphic under-sampling for key orbital parameters (precession), poor core recovery, thus, poor biostratigraphic constraints, poorly resolved records, and lack of multiple robust, time-equivalent series for parallel investigation. Nevertheless, suitable time series were identified for every Cretaceous stage with the exception of the Campanian. Case studies for the Maastrichtian and Albian Stages will be highlighted with a discussion of applications.
See more from this Division: Topical Sessions
See more from this Session: The Astronomically Forced Sedimentary Record: From Geologic Time Scales to Lunar-Tidal History (Posters)