CHRONOS Cyclostratigraphy Tools: Astronomical Calibration of Geologic Time at 0.02 to 0.40 Myr Resolution

Linda A. Hinnov
Johns Hopkins University, Baltimore, MD

A fundamental product of the virtual CHRONOS system is access to data and techniques used to calibrate geologic time. An important innovation in the Geologic Time Scale 2004 was the use of astronomically forced stratigraphy, or cyclostratigraphy, to define geologic time over 0-23.08 Ma at an unprecedented resolution of 0.02 myr. In addition, 'floating' astronomical time scales were proposed for entire epochs and stages in the Paleogene and all three Mesozoic periods. Some of these calibrations used a new astrodynamical model with an accurate ephemeris for Earth's orbital parameters to 250 Ma. Accordingly, CHRONOS plans to host the tools and models that are used for the astronomical calibration of cyclostratigraphy. This involves the development of a time series analysis toolkit customized for cyclostratigraphic applications, but appropriate for analysis of any sampled, sequenced data. Online, interactive modules will perform interpolation, tuning (correlation), multivariate spectral analysis, filtering, demodulation, and insolation modeling. The toolkit will enable CHRONOS to coordinate community projects working toward a continuous, astronomically calibrated time scale for the entire Cenozoic-Mesozoic, to host a "global composite cyclostratigraphic standard," and to promote prospecting for astronomical signals in Paleozoic cyclostratigraphy. Astronomically calibrated geologic time with a 0.02 to 0.40 myr resolution represents a major breakthrough in geosciences. Estimates of rates and magnitudes for a wide range of Earth system processes that can be examined only in the context of Earth history, e.g., paleoclimatology, geodynamics, geochronology, geochemical cycles and biotic evolution, will be improved by an order of magnitude over what is possible today.