some problems that interest me

It is very isolating here in Texas, and recently, even more so, as a number of responsibilities and other issues keep me from traveling to as many conferences, workshops and university visits as I used to.  I still get out from time to time and I of course read the literature voraciously, but sometimes a little isolation, punctuated by a few forays into the outside world and a few invasions into our own world, is not such a bad idea. A little isolation actually helps me focus on problems that interest me. If I kept popping my head into conferences, my mind would be overwhelmed, and I would feel compelled or pressured to catch up to everyone in the community and then get nothing done because I wouldn't be able to focus.  So the pattern is... isolate, focus, think, wander, think, focus, find yourself in a rut, pop your head into the outside world, learn what others have to say, then isolate, focus, think, wander, think, focus, find yourself in a rut and so forth.  Seems random, but methodically random.

In any case, the other night, I asked myself what are the problems that most interest me right now.  So here is a list.  Disclaimer. I am in no way suggesting that these are big problems.  In fact, it's also possible that they are already solved, only that I haven't quite caught up with the literature.  Follow at your own peril and don't blame me if you find yourself squandering your time.

1. It is time to revisit the origin of the calc-alkaline and tholeiitic differentiation trends, the two most important differentiation trends in the rocky parts of the solar system.  Is it due to redox effects, differences in water, crustal contamination, amphibole fractionation, magnetite fractionation (and redox), melt-rock reaction, or all of the above.  Surprisingly, there's no consensus, even after almost 100 years of study on this.

2.  What are melt inclusions, really?  Do they really represent primary or primitive melts and therefore tell us about the conditions of their source regions?  Or do they instead represent local, boundary layer liquids on the micron to mm lengthscales, in which case, they may tell us more about the physics of magma chamber dynamics.

3. Deep Sulfur Cycle. Where does the S in volcanoes actually come from?  The mantle?  Subducted crust?  Crustal contamination? 

4.  Whole-Earth Carbon cycling.  What is the redox state of C being subducted?  Is it, in net, different from that coming out of volcanoes?  Whatever the answer, the implications are big.

5.  Ore deposits. Enough said.  I should start doing something useful in my career for once.

6.  Origin of O2 in the atmosphere. Ok, this is a funny one.  Clearly it's a fashionable question, but there's still lots of debate.  Recently, a lot of emphasis has been placed on the role of the deep Earth, such as changes in redox state of mantle, the average pressures of magma differentiation or eruption, etc.. My shameless bias is that this not where the answer lies.  I have some thoughts, but you'll probably think I'm stupid if I describe them here, so, for now, I'll keep my dumb thoughts to myself.

7. Origin of intraplate magmas?  Hmmm... why does western USA look like east Asia? Plume? Or something more familiar...definitely someone should look at this.

8.  Why do arcs migrate and terminate?

9.  How fast do arcs grow vertically?

10.  How extensive is mafic-felsic magma mingling? This is a very loaded question.

11.  How are high Si rhyolites formed?  Or how do high Si liquids segregate?

12.  Are all mafic enclaves of igneous origin?  I doubt it.  The question is how much have a metamorphic origin. Ok, this is probably boring (but not to me!)

13.  Using nucleation rates and diffusion rates to examine kinetics of exsolution

14.  paleo-thermometry for peridotites

15.  the physical significance of biotite-rims on mafic enclaves.  ok... getting esoteric here. there's a good reason why this is interesting.

16.  speciation, role of dispersal and catastrophes.

17.  using REE disequilibria to get at cooling rates.

18. long-term climate change; my favorite right now, but I've stopped talking about it because the paper's been rejected 5 times now... soon to go into my paper graveyard.

I am sure 5 years from now, I will laugh at how naive these problems are.  I wish I had written a similar list 5 and 10 years ago just for comparison.  Hopefully, I'm not reinventing wheels.

p.s. there are some problems that don't interest me anymore, but I suppose it's not wise for me to list them in a public forum.