New Research Opportunities in the Earth Sciences - New Research Opportunities in the Earth Sciences - page 47

• The role of climate and tectonics in surface processes and landscape

evolution;

• feedbacks and linkages between climate and surface processes with mountain

building and decay, shoreline advance and retreat; and

• Linkages among climate, surface processes of erosion, transport, and

sedimentation, and deep Earth lithospheric processes.

These linked research areas offer exciting new opportunities to broaden our
understanding of the fundamental controls on Earth surface processes and their
influences on the world's landscapes.

Role of Climate and Tectonics in Surface Processes and Landscape Evolution

While one could hardly imagine a more striking contrast than that between the
slow evolution of hard, dense tectonic plates and the fluid, rapidly changing
atmosphere, the connections between the climate and tectonic systems are far deeper
and more subtle than commonly imagined (NRC, 2010a). Climate, tectonics, and
erosion interact over timescales ranging from individual storm events or earthquakes
to millions of years over the course of the evolution of a mountain range. The
importance of climate and climate variability is central to understanding both the
geomorphological impacts of shallow crustal processes over short timescales and how
such processes integrate up over longer timescales to influence landscape evolution.
A quantitative, process-based understanding of the linkages among climate,
hydrology, geomorphological processes, ecosystems, and landscape evolution is a
primary goal of research on Earth surface processes. Fundamental to achieving this
goal is the development of transport laws that mathematically characterize the
controls on rates of processes shaping Earth's surface. While significant progress has
been made in developing transport laws for a variety of processes (Dietrich et al.,
2003), transport laws are still lacking for processes as fundamental as landslides,
glacial erosion, and chemical erosion. In addition, the fundamental controls on one of
the basic components of the rock cycle, the breakdown of rock into erodible debris, is
poorly understood. The formulation of process laws allows quantification of the
driving phenomena and thereby rigorous exploration of questions of sensitivity of
landscape response to climate change and numerous feedbacks between climatic,
hydrological, geological, and geomorphological processes.
The linkages among surface processes and climate with tectonics also have
societal implications on human timescales in the role that sedimentation and erosion
play in the distribution and rates of displacement of active faults. Landforms and
sedimentary deposits preserve records of past earthquakes and deformation that are
used to evaluate recurrence intervals for active faults and assessment of seismic
hazard. Recent paleoseismological observations of migration of deformation between
fault strands over thousands of years (Dolan et al., 2007) challenge traditional views
of steady fault slip due to far-field plate motions, with important implications for
seismic hazards, earthquake clustering, fault growth, and fault interactions .