A wavelet-based workflow for cyclostratigraphic studies using the WaverideR R package

Cyclostratigraphic studies are based on accurately identifying astronomical cycles in the geological record. In excellent geological records, observed cycles can be directly coupled to their corresponding astronomical cycles. In more complex records spectral analysis techniques are needed to identify astronomical cycles. Most cyclostratigraphic studies utilise spectral analysis techniques based on the Fast Fourier transform (FFT). FFT-based spectral analysis techniques are excellent in identifying orbital cycles when the signal is stationary (e.g., the sedimentation rate is constant). To track changes in the sedimentation rate, a sliding window-based FFT analysis is often implemented, resulting in a frequency versus depth/time plot highlighting frequency changes and/or changes in the sedimentation rate. Windowed FFT-based techniques have one significant drawback: the window size has a fixed length, which limits the frequency range that can be analysed. The Continuous Wavelet Transform (CWT) avoids this drawback because the wavelet scales proportionally to the length of the analysed period. Current wavelet-based software/packages lack the features needed to complete a cyclostratigraphic study; therefore, the WaverideR R package (https://stratigraphy.eu/downloads) was developed, which contains all the essential functions required to do a CWT-based cyclostratigraphic analysis. To highlight the functionalities and versatility of the functions of the WaverideR R package, set functions are applied to three records; the Holocene Total Solar Irradiance (TSI) record, the Miocene ODP 926 greyscale record, and the Devonian Sullivan core magnetic susceptibility record.  The TSI record analysis highlights the WaverideR package's ability to change the omega (cycles within a wavelet) and extract cycles from the wavelet directly. The study of the Miocene ODP 926 greyscale shows how the WaverideR package can directly extract astronomical cycles in the depth domain and anchor this astronomical cycle to the astronomical solution. The analysis of the Devonian Sullivan core magnetic susceptibility record shows how the WaverideR package can trace the 405 kyr eccentricity cycle in a wavelet spectrum and create a floating age model, identify cycles in the time domain and then extract those cycles and the features of those extracted cycles such as its spectral power and its amplitude from the wavelet spectra.