http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#discussion http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7516 Some of the other workshops have tackled this question and come up with resources about these questions in their own disciplines. See http://serc.carleton.edu/NAGTWorkshops/earlyearth/questions/index.html for an example from the Early Earth Workshop in 2007.
We had come up with two ideas along this line for the Deep Earth - the Plume Debate which Brennan's talk and resources give lots of material to work with, and what actually drives Plate Tectonics. If you have ideas for Key Questions or materials/information that should be on pages about these questions please submit them here so that we can start building this really interesting and important resource.]]> John McDaris 1267202220 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7516 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7525
Length scales and time scales for mixing in the mantle.

Light elements in the core.]]> Wendy Panero 1267202520 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7525 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7540
Although that data may be outdated, the graphs might be useful starting points from which to move to 'better' and newer data sets, as they are relatively simple to explain and generally make intuitive sense. Using NUVEL derivatives to get better plate velocities and directions of motion, using GIS to more accurately estimate plate sizes and calculate plate volumes, using tomographic data to more accurately constrain how much of each plate is 'hidden' in the mantle but still attached, using newer mineral physics data to better estimate densities of minerals that are in parts of plates which are deep in the mantle could partly or all be used to better test hypotheses about which plate forces are most important.

I would also wonder for forces such as drag, how much its effects depend on depth of lithosphere/asthenosphere boundary and temperature at the boundary, which might have a pretty strong control on the viscosity contrast across the L/A boundary.

A lot of the specifics for data to answer these questions I suspect is well beyond me, but I'd be glad to help gather/collate data in whatever way I can...]]> Ben Edwards 1267203300 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7540 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7550 http://www.iris.edu/hq/lrsps/. About half of the 10 challenges relate to the deep Earth, including
How do magmas ascend and erupt?
What is the lithosphere-asthenosphere boundary?
How do plate boundary systems evolve?
How do temperature and composition variations variations control mantle and core convection?
How are Earth's internal boundaries affected by dynamics?]]> John Taber 1267206900 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7550 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7552 What is the oxygen fugacity in the mantle? Since there is some evidence that suggests that Fe+2 may disproportionate into Fe0 and Fe+3 at very high pressure, is this even the right question to be asking? ]]> Pamela Burnley 1267217940 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7552 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7564
What are we currently able to predict about the future, and what can we expect to learn to predict at a later time, as our understanding advances?

What aspects of phenomena make them predictable, or impractical to predict?

The topic of predictability carries with it fundamental issues such as probability, chaos, the nature of models, and questions about what we can say about the time and place of future events.

Concerning the deep Earth, some issues are what we can predict about future changes in the magnetic field, the future configuration of plate boundaries, and seismic events caused by plate motions.

Kindred issues can be raised about the past. How much and what detail can we recover about past events, and what information is lost forever? Concerning the deep Earth, we can ask about the history of the differentiation of materials, the signature of the history of magnetic field, evidence of changes in plate boundaries, and many more questions.

... and while we are on the topic of what information about the Earth is accessible and what is not, we can consider what we can and cannot learn about phenomena or places that we can only study from a distance, such as the deep Earth. What are the surface manifestations of deep Earth processes? What experiments can we perform that can yield information about the deep Earth, in lieu of our going there?]]> Glenn Richard 1267264020 http://serc.carleton.edu/NAGTWorkshops/deepearth10/discussions/key_questions_a.html#post7564