Signal processing methods in stable isotope chronostratigraphy: Applications to St. Stephen's Quarry and Baldwin County, Alabama
Allan Abbott, I. Lerche, GERALD R. BAUM · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 1994
This study applies quantitative signal processing methods to four geologic records. The data analyzed are profiles of carbon 13 and oxygen 18 isotopes extending from Eocene through Oligocene for two well sites located on the Alabama coastal plain: the Bay Minette core located in Baldwin County, and a core from St. Stephen's Quarry. Autocorrelation functions of each of the four records are constructed as first approximations of a signal, power spectral analysis then performed, and a noise-minimization, matched filter technique used, designed to enhance signal to noise ratios in time series data, to non-linearly update the signal by iteration. The applications determine the level of signal in the data and the strength of the residual noise. By reprocessing the data using half-time steps and recalculating the signal to noise ratios in the records, confirmation of signal by the filter technique is checked for the possibility of compromised information which could have been due to the data interpolation scheme. The results from each of the four profiles demonstrate that the records may be useful for both chronostratigraphic interpretation and also for cross-correlation of geologic and oceanographic events in time and location, because all signal strengths are high relative to the residualmore » noises.« less