Comparing 545 Million Years of Sea-Level Change: New Insights from the TopoChronia QGIS Plugin

Engineering structures known as check dams are built with the intention of managing streams. The effectiveness of such structures can be expressed by quantifying the reduction of the sediment flux after their implementation. In this contribution, we estimate and compare the volumes of sediment transported in a mountain stream for engineered and non-engineered conditions. We found that without check dams the mean sediment flux would be ca. 10 times larger in comparison with the current situation.

Sediments deposited within river channels form the stratigraphic record, which has been used to interpret tectonic events, basin subsidence, and changes in precipitation long after ancient mountain chains have eroded away. Our work combines methods for estimating gravel fining with a landscape evolution model in order to analyze the grain size preserved within the stratigraphic record with greater complexity (e.g. considering topography and channel dynamics) than past approaches.

Deep-time climate simulations are challenging since sedimentary data are too sparse and uncertain to fully constrain initial and boundary conditions. By exploring a wide range of initial conditions, we find three alternative steady states with a temperature difference of around 10 °C in simulations using the Permian-Triassic paleogeography. This opens the possibility of explaining climatic variations in Early Triassic geological records through tipping mechanisms between steady states.

The Middle Eocene Climatic Optimum (MECO) was a global warming event that took place 40 Myr ago and lasted ca. 500 kyr, inducing physical, chemical, and biotic changes on the Earth. We use stable isotopes to identify the MECO in the Eocene deltaic deposits of the Southern Pyrenees. Our findings reveal enhanced deltaic progradation during the MECO, pointing to the important impact of global warming on fluvial sediment transport with implications for the consequences of current climate change.