Collaborative Research: Reconstructing paleo-sediment flux from river deposits: toward quantifying sediment discharge from bedform to basin scale

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Constraining the quantity of sediment carried by ancient rivers provides a window into landscape conditions throughout Earth’s history. It also facilitates the prediction of where hydrocarbon, water, mineral, and geothermal resources are buried in sedimentary basins. This project aims to advance our understanding of how sediment is transferred through the beds, bars, and levees of rivers in order to help i) answer questions about river response to changes in tectonics, climate, and sea level, ii) understand controls on river movements on Earth and other planets, and iii) predict the best places for underground energy development, mineral exploration and aquifer management. This project is providing training opportunities for students from underrepresented groups, thereby helping to develop a diverse geoscience workforce. This research is also producing large datasets—made available via data repositories— of experimental bedform characteristics and scaled stratigraphic measurements that will be a valuable teaching resource, and useful for geologists, geomorphologists, and civil engineers alike. In addition, the researchers are developing mini-tutorials and virtual field trips that can be used as classroom exercises for students and outcrop-interpretation exercises for scientists, including those with limited access to field experiences. Images and image interpretations are being incorporated into the machine learning project to support the development of automated outcrop interpretation tools. This project is leveraging advances in geomorphology and sedimentary geology to quantitatively connect the role of sediment supply in sediment-transport processes across multiple scales to stratigraphic products. A combination of physical experiments, modeling, and field observations is being used to refine physical constraints on sediment transport rates of bedforms, bars, and channels, and to quantify how the shape and preservation of these features in the stratigraphic record relate to sediment-flux conditions at different scales. This insight is being applied to deposits of the Spanish Pyrenees – a system with robust basin-scale sediment-flux constraints – as a field calibration exercise. Subsequently, the developed approaches can help quantitatively test hypotheses about sediment-supply changes that occurred in response to the Paleocene-Eocene Thermal Maximum climate-change event. These efforts are yielding new insight into how sediment is partitioned between distinct but interrelated morphodynamic processes in fluvial landscapes, and providing a guide to how environmental and land-use change can affect river mobility on centennial to millennial timescales.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.