NEW DIRECTIONS AND CHALLENGES IN TECTONIC GEOMORPHOLOGY

Surface processes act to change elevation through erosion and deposition while tectonic processes depress or elevate the surface directly. Interpreting this interaction with knowledge of the surface process patterns and rates provides valuable information about tectonic processes at time scales longer than the typical earthquake cycle (years) and shorter than the geologic time scales (Myr) over which a structural system may significantly evolve. Thus, it should be possible to more completely define the surficial displacements associated with a given set of deformation sources. At orogenic spatial scales (10s km), surface and tectonic processes may have a complete feedback such that the surface processes actually influence the structural architecture of the mountain belt the action of which may further localize erosion. Essential data for the study of tectonic geomorphology are high resolution topography and imagery (so that landforms can be defined at an appropriate resolution) and good control for ages of landforms, exhumation, and exposure over Pliocene to Quaternary time scales (cosmogenic radionuclide dating and low temperature thermochronology). Combining these and other data with models requires geospatially-enabled interpretive cyber-environments that can rapidly handle both synoptic views and detailed query. Complete mechanical modeling of coupled surface and tectonic processes remains elusive. Surface process models are not typically as deeply physically rooted probably because of the heterogeneity of the landscape, the fine scale required to appropriately represent landforms (10s of m), and a poor understanding of rates of surface processes and their sensitivity to climatic modulation. Elastic, viscous, plastic (and their combinations) rheologies are often employed with numerical implementations to represent crustal or lithospheric deformation and may be coupled with the surface process models. The structural tools are also challenged by the heterogeneity and granularity of the structural systems. Nevertheless, the quantification and interpretation of the interaction of tectonic and surface processes provides a rich set of research opportunities at a frontier in structural geology and tectonics.