Download The Grand Challenges, Leading Edge Ideas, and

Grand Challenges, Leading Edge Ideas,
and Frontiers in Tectonics
K.V. Hodges
School of Earth and Space Exploration
Arizona State University
Roadmap
• National Research Council
perspectives
• Perspectives of colleagues
• Getting to the heart of the
matter
• Personal perspectives on
teaching integrated materials in
the 21st Century
The NROES Report
• Charged to “identify high-priority
new and emerging research
opportunities in the Earth
sciences over the next decade”
• Charged “to suggest new ways
that EAR can help train the next
generation of Earth scientists,
support young investigators, and
increase the participation of
underrepresented groups in the
field”
NROES Focus Recommendations
• The Early Earth
• Thermo-Chemical Internal Dynamics and Volatile Distribution
• Faulting and Deformation Processes
• Interactions among Climate, Surface Processes, Tectonics, and Deep Earth
Processes
• Co-evolution of Life, Environment, and Climate
• Coupled Hydrogeomorphic-Ecosystem Response to Natural and Anthropogenic
Change
• Biogeochemical and Water Cycles in Terrestrial Environments and Impacts of Global
Change
• Recent Advances in Geochronology
The Early Earth
• Many uniquely critical events occurred early in Earth’s history: delivery of the material
that built Earth; formation of the Moon; and the differentiation events that formed the
core and earliest crust, the oceans, and the atmosphere. Earth’s early history set the
stage for its subsequent dynamic and geochemical evolution, from an environment
dominated by impacts and magma oceans to the habitable environment dominated
by the plate tectonics of today.
How did plate tectonics arise on Earth?
On what time frame did it happen?
Why is Earth the only planet in the solar system that appears to have evolved to that
point?
Thermo-Chemical Internal Dynamics and Volatile
Distribution
• The huge dynamic circulation systems in Earth’s mantle and core circulate heat and
materials, drive the long-term evolution of continents, generate the magnetic field,
and cycle volatiles into and out of the interior, maintaining bulk chemistry of the
oceans and atmosphere. Resolving the present-day configuration and processes of
the mantle and core convective systems with high resolution is a key undertaking for
developing models of the past and future evolution of the system, the thermal
evolution of Earth, and the volatile flux in Earth.
What are the relationships among planetary and lithospheric dynamics?
How did the continents come to be?
Faulting and Deformation Processes
• Exciting discoveries, driven by increased instrumentation around fault zones, have
been made regarding the spectrum of faulting processes and mechanisms. These
present an opportunity to make significant progress on understanding faulting,
related deformation processes, and resulting earthquake hazards.
What are the relationships among fault zone dynamics and regional- or lithospherescale deformational processes?
Interactions among Climate, Surface Processes,
Tectonics, and Deeper Earth Processes
• The broad interactions among climate, Earth surface processes, and tectonics are an
area of compelling research opportunities that center on interactions among
topography, hydrology and hydrogeology, physical and chemical denudation,
sedimentary deposition, and deformation in tectonically active mountain belts.
How do orogenic systems influence climate?
How does climate influence orogenic systems?
Can we disentangle the two?
Co-evolution of Life, Environment, and Climate
• The deep-time geological record has provided a compelling narrative of changes in
Earth’s climate, environment, and evolving life, many of which provide analogs,
insight, and context for understanding human’s place in the Earth system and current
anthropogenic change.
How does tectonics influence societal evolution?
Coupled Hydrogeomorphic-Ecosystem Response
to Natural and Anthropogenic Change
• Understanding the response of large scale landscapes and ecosystems to
disturbance and climate change requires greater mechanistic understanding of the
interactions and feedbacks among hydrological drivers, landscape morphology, and
biotic processes.
If tectonics can influence climate and landscape physiography, in what ways does the
evolution of orogenic systems influence ecosystem evolution?
Biogeochemical and Water Cycles in Terrestrial
Environments and Impacts of Global Change
• Humans are altering the physical, chemical, and biological states of and feedbacks
among essential components of Earth’s detailed surface system. At the same time,
atmospheric temperature and carbon dioxide levels have increased and are
impacting carbon storage in the terrestrial environment, the water cycle, and a range
of intertwined biogeochemical cycles and atmospheric properties that feed back on
climate and ecosystems.
What does the coupling of climate and tectonics predict regarding the long-term
influence of tectonic activity on the hydrosphere?
How strong are the feedback loops between tectonics and geochemical and
biogeochemical cycles?
Is tectonics somehow different in the Anthropocene, or is that simply a breathtaking
conceit?
Recent Advances in Geochronology
• The global span of the geosystems involved requires synoptic observations provided
by global networks of geophysical, geochemical, petrological, and environmental
facilities and data collection efforts. EAR should explore new mechanisms for
geochronology laboratories that will service the geochronology requirements of the
broad suite of research opportunities while sustaining technical advances in
methodologies.
What are the timescales over which different tectonic processes operate?
What is the pace and tempo of tectonics?
How are consistent are geodetic, neotectonic, and geologic constraints on the
kinematics of deformation fields?
How consistent are rates as measured on the millenial vs. million-year timescales?
Key Educational Concepts from the Community
• Physics rules! (Dynamics, mechanics [e.g., isostacy], rheology, strength)
• Value of multiple models (critical wedge, potential energy, viscous sheet)
• Limitations of models for more than understanding basic concepts (too much critical wedge
can be a dangerous thing...)
• It all begins and ends with field observation
• The present is the key to the past (from plate tectonics to active continental tectonics)
• Exploit unusual ways to monitor deformation fields (e.g., seismic anisotropy, geodetically
constrained crustal flow fields, seismicity maps)
• Exploit the linkage between tectonics and geomorphology
• Remember that decoupling within the lithosphere can confound strain field estimations
• Modern lithospheric structure represents only a moment in time
The Heart of It...
• Tectonics is the most fundamentally integrative “field” within the earth sciences. To do
it well, you must be a polymath, with (at least) a firm grasp of the concepts and
concept interactions of geochemistry, geomorphology, geophysics, and structural
geology.
• Teaching tectonics should be as integrative as the field itself. Tectonics is the perfect
capstone course for a modern earth science curriculum; it allows the instructor to
reinforce nearly every other foundational subject
Transdisciplinary Teaching
• Less about facts and basic concepts (which can be acquired very effectively on line
these days) and more about concept relationships
• A focus on cause, effect, and that nebulous region in between
• Emphasize the power of integration
• Emphasize the importance in science of multiple working hypotheses and the healthy
debate that characterizes the best science
• Case studies are extremely well suited for this sort of application