A Stratigraphic Framework for the Preservation and Shredding of Environmental Signals

Abstract

The stratigraphic record contains unique information about past landscapes and environmental change. Whether landscapes faithfully transmit signals of environmental change to stratigraphy is unknown because autogenic processes, such as river avulsion, can obscure signals prior to long-term stratigraphic storage. We develop a theoretical framework that predicts when a sediment flux signal will be transferred from the landscape to stratigraphy. This threshold magnitude is a function of signal duration. The magnitude is set by the maximum rate of autogenic volume change of the landscape, which decreases with increasing time window. Physical delta experiments, specifically designed to test our theory, demonstrate that only sediment supply signals with a magnitude greater than the threshold are stored in stratigraphy, supporting our theory. This framework allows us to assess the fidelity of the stratigraphic record to archive past signals of environmental change and predict the short- and long-term impact of current anthropogenic forcing on landscapes.