Lost in translation: Defining thresholds for the storage of environmental signals in stratigraphy
Kyle M. Straub, DeFord Lecturer
Department of Earth and Environmental Sciences, Tulane University
Alluvial basins provide important records of climate and tectonic changes on Earth, as well as information about how land surfaces evolve under different boundary conditions. These deposits also contain important energy and water reserves and will serve as hosts for carbon capture and storage. Consequently, our ability to reliably interpret and predict stratigraphic patterns is fundamentally important both scientifically and in its bearing on broader society. While stratigraphy is our best record of paleo Earth-surface dynamics, the record also contains signiﬁcant gaps over a range of time and space scales. These gaps result from stasis on geomorphic surfaces and erosional events that remove previously deposited sediment. Building on earlier statistical studies, we examine the fidelity of the stratigraphic record in laboratory experiments where the topography of aggrading deltas was monitored at high temporal and spatial scales. In these experiments, we also quantify the depositional architecture that controls the 3D structure of the strata. This architecture is influenced by both stochastic (autogenic) and deterministic (allogenic) processes. Specifically, we investigate the temporal and spatial scales necessary for changes in forcing conditions (including sea level and/or sediment flux) to be stored in the stratigraphic record. This work helps improve efforts at recovering meaningful data about autogenic processes from stratigraphic datasets, isolating signals of changing boundary conditions in ancient basins, and modeling and predicting stratigraphy in alluvial basins.