Giant radial dike systems that on average are several hundred kilometers in radius can be found on Earth, Venus and Mars. To date, however, it has been unclear how these impressive volcanic features might originate. For such systems to form, massive quantities of magma ascending from the mantle must encounter both a stress field that favors a radial dike configuration and something that redirects ascending magma laterally at shallow depths within the lithosphere. The former condition is straightforward to create via large-scale flexural uplift in response to plume impingement, underplating, or a similar mechanism; however, the stress state resulting from this process strongly favors continued ascent and eruption, inconsistent with evidence of long-distance lateral transport of magma through the radial dikes.
In a paper recently published in the journal Icarus, Dr. Gerald Galgana, Dr. Patrick McGovern (colleagues from the Lunar and Planetary Institute in Houston, TX) and I have demonstrated that initial eruptions related to flexural uplift can produce a surface load (e.g., a large volcanic edifice) that acts to counter the uplift, suppressing upward flexure and simultaneously creating a stress cap of sufficient magnitude that lateral redirection of magma into radial dike systems becomes likely. This exciting new understanding links mechanical processes acting upon the lithosphere directly to the volcanological outcomes, improving our insight into the formation and evolution of some of the largest magmatic systems and radial dike swarms identified on multiple planets.
For more information: Galgana, G.A., E.B. Grosfils and P.J. McGovern, 2013. Radial dike formation on Venus: Insights from models of uplift, flexure and magmatism. Icarus, 225, 538-547.
Posted in Publication, Research | Comments (0)
I’ve often been asked, as a faculty member at a small liberal arts college — a setting traditionally and fiercely dedicated to the pursuit of excellence in teaching — why I want to perform research. Sure it’s intellectually delightful to explore and to challenge myself to advance what we know about a research subject in which I’m interested, like physical volcanology or planetary science, but it takes a seemingly never-ending stream of energy to write successful grants, pursue questions that don’t always yield fruitful outcomes, publish the results obtained when something new is learned, etc. Wouldn’t that time and energy be better spent honing my skills as a teacher? An answer to this is articulated succinctly in a quote that comes from a 1-page article (on pg. 47 of course!) in the Summer 2013 Alumni Magazine published by my undergraduate alma mater, the College of William and Mary:
“What is discovered in research one day is taught in the classroom the next, and then employed as a tool of economic development, innovation and, in some cases, national defense. The false notion that teaching in universities serves students but that research in universities does not betrays a profound misunderstanding of how academic institutions become great — and stay great.” — R.M. Gates, W&M ’65
There are clearly connections to teaching when I involve and mentor students, but it is important to recognize as well that my teaching and capabilities as an instructor usually benefit even when no students are directly involved in the research I perform. As a liberal arts instructor then my answer to the question I’m often asked is simple: I believe that doing research makes me a better teacher.
In my view, striving to become a more effective teacher is a goal which more than justifies the time and energy required to perform scholarly research, and I am grateful for the opportunities I have had in this arena. Of course, the fact that I also derive deep satisfaction from gaining new insights with the potential to help people directly, or that simply increase our knowledge in a more abstract way about the fascinating solar system in which we reside, is simply icing on the proverbial cake!
Addendum (7/27/13): In its 2013 list of top colleges in the US, Forbes ranked Pomona College #2 nationally. While ranking results like this should always be taken with a big grain of salt, I think it likely that the incredible dynamicism of my teacher-scholar colleagues plays a central role in our continued success where such evaluations are concerned…
Posted in Research, Students | Comments (0)