WetSlide: Weathering in landslide deposits
Chemical weathering
Silicate and carbonate rocks are dissolved by acidic water at the surface of the Earth. This dissolution (or chemical weathering) controls the formation of soils, and it is a major component of Earth’s carbon cycle. The most common acid in natural waters is carbonic acid which forms when atmospheric CO2 dissolves in water. Where carbonic acid weathers silicate rocks, cations (like Calcium) are produced, are transported to the ocean, and precipitated as carbonate. By this process, the CO2 from the atmosphere is locked up in the rock record. The faster rocks weather, the more CO2 is removed from the atmosphere.
The role of erosion
In addition to acidic water, fresh mineral surfaces are required for chemical weathering. Minerals are exposed at Earth’s surface through erosion by water, wind, and mass movements, and erosion rates are fastest in actively uplifting mountain ranges such as the Himalaya, Taiwan, and New Zealand. The rapid supply of fresh minerals in these mountains has been linked to efficient weathering, and several studies have hypothesized that the decrease of CO2 in the atmosphere over the Cenozoic (~the last 50 Million years) and the associated cooling of the climate was linked to the growth of the Himalaya. However, despite years of research, the links between erosion and chemical weathering have not been fully constrained.
Weathering in landslide deposits
Many existing datasets and models for chemical weathering are based on the development of soils, but in active mountain ranges, mass movements (such as landslides) dominate the production of fresh sediment. With WetSlide, we aim to develop a calibrated model for weathering of rocks in landslide deposits. More and more data emerge that constrain how often landslides of different sizes occur in active mountain ranges. Here, we will build a dataset of solutes exported from landslide deposit and how these solutes change as a landslide deposit ages. Moreover, we will estimate the time that rocks spend in landslide deposits before they are removed from hillslopes. With these components, we will build “weathering-time” functions that are the basis to our landslide-weathering model.
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 841663.
