[S-CG64] [EE] Morphodynamics and Genetic Stratigraphy for Understanding Landforms and Strata

[SCG64-12] Lost in translation: Defining thresholds for the storage of environmental signals in stratigraphy

*Kyle M Straub¹ (1.Tulane University of Louisiana)

キーワード：Deltas, Stratigraphy, Experiments

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. 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. The resulting stratigraphic architecture is influenced by both stochastic and deterministic processes. We start by quantifying the temporal scales that climatic perturbations must possess to be stored in stratigraphy via geochemical proxies. Then we investigate the temporal and spatial scales necessary for changes in forcing conditions, including sea level and/or sediment flux, to generate signals in the physical stratigraphic record. Finally, we examine how environmental stochasticity can further complicate signal identification. 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.