On the Relationship between Macrostratigraphy and Geological Processes: Quantitative Information Capture and Sampling Robustness

Spatial and temporal patterns in the sedimentary record are controlled by a wide range of forcing mechanisms. Macrostratigraphy uses the temporal ranges of gap-bound rock packages, compiled separately for different geographic locations, to quantify these patterns. The total number of gap-bound packages (D) and the rates of package initiation and truncation (p and q, respectively) distill depositional geometries into time series that preserve information on both the spatial extent and the temporal continuity of deposition. These macrostratigraphic quantities should, in principle, relate quantitatively to the underlying forcing mechanisms that govern sedimentation. Here, we use a numerical model of continental-margin sedimentation to test the extent to which time-varying forcing mechanisms, including subsidence, sediment supply, and sea level change, can be detected quantitatively by the application of macrostratigraphy. Spectral and information-theoretic analyses of time series of D, p, and q show that (1) all three quantities contain significant information on the sea level change, sediment supply variability, and subsidence patterns specified in the model input and (2) they convey the relative strengths of multiple forcing processes and how the relative importance of these processes varies with temporal resolution. We also find that the process information of p, q, and D is very robust to incomplete spatial sampling of the deposits. Our results suggest that D, which reflects variations in the area of sediment coverage and its temporal persistence, may afford the single best macrostratigraphic quantity for capturing the entire range of forcing mechanisms. Macrostratigraphy thus extends many of the well-known links between sequence architecture and sedimentary processes into a quantitative framework for statistical analyses of entire basin-fill successions.