266-10 Spectral Characterization of Tidal Signal Preservation in Neoproterozoic Rhythmites Using Grayscale Stratigraphy and Time Series Analysis.

Session: The Neoproterozoic Earth and Life Co-evolution (Posters)

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Abstract:

High resolution stratigraphic analysis of fine grained tidal rhythmites provides a strong dataset to reconstruct paleotidal cyclicity and sedimentary dynamics in the Neoproterozoic. This study applies grayscale stratigraphy, spectral analysis, and calibrated tuning to estimate tidal cyclicity in a ~9.2 cm section of the Neoproterozoic Aaron Formation. Using 2π multitaper spectral analysis and Taner bandpass filtering, we identify statistically significant peaks corresponding to modern tidal constituents semidiurnal (M2, 0.517434 days) and diurnal (K1, 1.003 days). Residual analysis indicates that amplitude modulation aligns with ~14 day spring-neap cycles, supporting temporal calibration across the stratigraphic profile (~0-45 days). A spectral envelope minimum at 2.113 cm aligns with a hypothesized low-energy depositional interval. Petrographic thin section analysis at this position shows textural and mineralogical indicators of reduced sedimentation rates, including fine grained detrital laminations, low bioturbation, and iron oxide banding. These data support a link between cycle completeness and periods of dynamic quiescence. The signal strength and coherence across the section suggest rhythmic deposition tied to astronomical forcing, rather than random spatial heterogeneity. Sediment accumulation during quiescent phases likely associated with neap tides preserves finer cyclicity and supports better signal clarity. In order to provide insights into sequence stratigraphy and paleogeophysical reconstruction in Precambrian marine environments, the combined grayscale-spectral-petrographic technique illustrates how tidal rhythmicity is preserved in sedimentary records. This study provides a template for evaluating sedimentary records where traditional fossil markers are absent and highlights how signal tuning to present-day astronomical periodicities can refine the temporal resolution of ancient depositional systems. The findings offer new directions for linking time-frequency analysis to basin-scale geophysical modeling and stratigraphic completeness assessments.

Keywords: Spectral Analysis, Stratigraphy Neoproterozoic, Sedimentation, Cyclicity.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-5794

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