Earth Surface Dynamics
Our primary objective is to establish and document physical models for the geologic processes operating at or near the Earth's surface. These geologic processes include (1) tectonic processes that deform rock or expose it at the surface, (2) geomorphic processes that convert bedrock to sediment and (3) climatic processes that control erosion and sediment transport. Towards this end, we have adopted a multi-disciplinary approach that includes three main components. First, is the construction of models based on physical laws, with an emphasis on thermal and landscape evolution models. The produced models are coupled with inverse methods, to calibrate model parameters against data. In particular, we are developing new techniques for the inversion of thermochronological data. Second is field experimentation. We conduct fieldwork, primarily in mountainous terrain, in order to collect data that can be used to unravel interactions between tectonics, erosion and climate. Our field sites include the Alps, Southern Alps of New Zealand, Andes, Himalaya, Western Scandinavia, Alaska and French volcanic islands. These studies often involve data collection for low-temperature thermochronology, luminescence dating and cosmogenic nuclide dating. Third is experimental work. Although several methods can be used, we have been particularly fascinated by our recent discovery of a new thermochronologic method based on luminescence dating. This system is revealed to have a very low closure temperature (down to 40-500C). This is the lowest closure temperature system ever observed to date, which is very appropriate to produce data that can be used to constrain landscape evolution models.