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Rio Bermejo headwaters, Andes, NW Argentina      Photo: Dirk Sachse

My primary research interests include landscape evolution and tectonic geomorphology, and more recently I became interested in the role that rivers play in the organic carbon cycle.

Rivers are sensitive recorders of landscape change, and can serve as a profound signal for active tectonic, climatic, biotic, and anthropogenic processes.

I am developing a new project in the NW Argentinian Andes, where the Rio Bermejo transports a significant volume of sediment and terrestrial organic carbon from the mountain range to the Paraguay River, which eventually reaches the Atlantic Ocean. The primary research questions I aim to solve include:

  1. Is dynamic topography influencing the planform geometry and flow regime of river systems draining the eastern flank of the Andes?
  2. How do leaf wax biomarkers evolve as they are transported downstream in a river system?
  3. How is organic carbon transported by the river and stored in the floodplain (at both bulk sediment and grain size scales)?
pescado-bermejo-confluence
Confluence of the Rio Pescado (draining from the west) and the Rio Bermejo (draining from the north) in NW Argentina.

My Master’s thesis resolved our understanding of mantle dynamics beneath the southwest United States through an intensive study of the incision history of the Rio Grande. Differential incision over both time and space may indicate dynamic topography when factors like climate change, lithologic strength, and erosion have also been evaluated as possible causes. I found that the long-term evolution of the Rio Grande was most heavily influenced by tectonics related to the post-30 Ma Rio Grande rift, broad-scale epeirogenic uplift of the southern Rocky Mountains, and altered topography as a result of volcanic activity. Rapid rates of incision after 640 ka are attributed to a wetter, more dynamic climate.

Rio Grande Incising into 2-5 Ma basalts on the Taos Plateau in northern New Mexico
Rio Grande Incising into 2-5 Ma basalts on the Taos Plateau in northern New Mexico

 

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