1» !(\ IT ,o31TY OF -jloLlBRAPY U AT UP \A-CHA?>' AIGN MAY o 3 ?nm Digitized by the Internet Archive in 2011 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/yearinreview199907univ utuuuui uunnm 19 9 9 YEAR REVIEW Department of Geology JNIVERSITY OF LLINOIS AT URBANA-CHAMPAIGN C. This diagram illustrates how the Song: fastest path through the Earth's solid inner core has shifted over Jncovering time, showing that the core moves at a faster rate than the rest of the Secrets of the Earth. Xiaodong Song's findings nner Core have been hailed as one of the most important discoveries of the century by Discover magazine. Assistant Professor Xiaodong ong has done groundbreaking any other. As luck would have rark using seismic data to better it, however, the inner core is not inderstand the Earth's core. Song exactly symmetric around the ecently came to the Department north-south axis. The fastest if Geology at Illinois from the path was found to be tilted ,amont-Doherty Earth about 10 degrees off the pole )bservatory of Columbia and the wave speed changes lat- Iniversity, where he had been erally in the inner core. esearching and teaching for three the outer core and the conducting Song and his Lamont colleague, ears after earning his Ph.D. in geo- inner core causes the inner core to Paul G. Richards, were able to observe ihysics from the California Institute of rotate a few degrees per year. These the inner core's movement by review- echnology. His Ph.D. research investi- few degrees translates to about 10 kilo- ing seismic data over the course of ,ated the properties of the Earth's core meters per year —clearly the core rota- about 10 years. They found that if they nd lowermost mantle. His work at tion is very fast in the context of geo- took measurements from the exact .amont provided observations proving logic time. However, until Song's work, same station (relative to the mantle) hat the Earth's solid inner core rotates no one had been able to observe or and used earthquakes from the exact t a faster rate than the rest of the prove this hypothesis. same point, they could observe a ilanet. This finding was listed as one "With this kind of speed, we change in seismic speed with time, if the most important scientific discov- should be able to observe the move- thus proving the core had rotated. ries of the century in Discover maga- ment," says Song, "but the trick was Song's next step is to use similar :ine and one of the most important figuring out how to do it." Song took seismic data to understand the proper- ireakthroughs of the year in Science. advantage of his Ph.D. research con- ties of the inner core. It is unclear It has long been theorized that the cerning the anisotropy of the inner whether the anisotropy of the inner nner core, which is solid, may move core. Seismic waves that go through core is caused because the core is a eparately from the rest of the Earth- the Earth go at different speeds and single giant anisotropic crystal or that ike a beach ball in water. In fact, the directions, depending on the composi- there are different phases of iron in the Earth's magnetic field is explained by tion of the part of the Earth it's travel- core or even a transition zone within he convective motions in the fluid ing through (see image). In his the inner core. Song hopes there are ore. This idea is known as the research, Song had found that the further clues about the composition )ynamo Theory. According to this the- inner core is not homogeneous and and motion of the core in the seismic iry, electromagnetic force generated by that seismic waves go faster along a data he has collected. he interaction of the magnetic field in roughly north-south axis than along Greetings Our "Year in Review" The year 1999 University. He is an isotope geo- and teaching program. We all owe Jay has seen a chemist and has been setting up a new a hearty thanks for his efforts on our number of mass spectrometry lab in the Natural behalf! I have become the department H changes in the History Building. Professor Tom head. Though I've been teaching g Geology Anderson, on our faculty for 32 years, structural geology, geotectonics, and Department. retired at the end of the fall semester. field geology at Illinois since 1983, this We are delight- Fortunately, Tom will continue his is my first experience with administra- ed to welcome research as an emeritus professor. We tion, so this fall was an intense learn- two new facul- look forward to adding two more new ing experience. I've really enjoyed the ty members to faculty members to our roster during opportunity to meet with our alumni the department. Professor Xiaodong the next year, for we are now in the and have been warmed by the contin- Song, a seismologist, came to Illinois midst of searches for a geomicrobiolo- uing enthusiasm that alumni have for from Cal Tech, via the Lamont- gist and for a new R.E. Grim Professor the activities of the department, and Doherty Geological Observatory. His in either mineral science or sedimenta- for the financial support that alumni research focuses on understanding the ry geology. We've clearly entered a provide through GeoThrust. nature of the Earth's interior. Already, growth mode and are excited about You may have noticed that, in his work demonstrating that the core building new and educational honor of the new millennium, we've does not spin at the same rate as the opportunities in the department. gone from publishing two alumni mantle has garnered international At the beginning of the fall, newsletters a year to publishing one headlines. Professor Craig Lundstrom Professor Jay Bass, who energetically Department of Geology "Year in joins us from the University of guided the department for the past Review". You'll find that this review, in California, Santa Cruz, via Brown two years, dove back into his research addition to popular news about departmental and alumni activities, also contains a record of research and Contents teaching activities in the department. We hope this information helps to give a sense of the scientific and education- al mission of the department. New Faculty: Xiaodong Song 1 Please enjoy this publication and Greetings from the Department Head stop by if you're in the area — NHB is New Faculty: Craig Lundstrom 3 having a bit of a face lift, with new Department News 4 paint and new lights in public spaces. Tom Anderson Retires 5 Otherwise, look for your departmental Undergraduate Activities. 9 friends at the receptions we sponsor at Geology Long Ago 14 the AAPG and GSA meetings. Annual Report 16 — Stephen Marshak News from Alumni and Friends 20 Year in Review is published once a year by the Department of Geology, University of Illinois at Urbana-Champaign, to summarize the activities and accomplishments within the department and news from alumni and friends. Department Head: Stephen Marshak ([email protected]) Staff Secretary: Barb Elmore ([email protected]) Editor: Deb Aronson Produced for the Department of Geology by the College of Liberal Arts and Sciences Office of Publications; designer: Pat Mayer. http://www.geology.uiuc.edu |; ,,| „ College of Liberal Arts and Science, I UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN ULULUbT LI! New Faculty A. Adjacent to Interface Top: Back-scattered Lundstrom electron images of peridotite shows clear Looks at differences between melt and mineral modes of "A" the Magmatic region closest to the basanite-peridotite Processes interface and "B" the region farthest from the interface. Craig Lundstrom recently joined the Bottom: Craig Geology Department as an assistant professor after completing a post-doc Lundstrom sitting at at Brown University. He is a geo- his newly assembled chemist who received his B.A. in mass spectrometer. chemistry from Colorado College and his Ph.D. in Earth Sciences from the University of California, Santa Cruz. spreading is a passive process. These Lundstrom uses uranium-series findings were published in Earth and (U-series) disequilibria to study mag- Planetary Science Letters in 1998. matic processes on the Earth. U-series In a related area of inquiry, isotopes have much shorter half lives Lundstrom has conducted experimen- than more conventional isotope sys- tal studies on the interaction between tems such as Sr. The half lives of the basalt and peridotite. He wants to isotopes Lundstrom studies (radium, understand how the melt interacts thorium and protactinium) range from with the mantle. Can basalt, for exam- 1,600 -350,000 years and thus can be ple, re-equilibrate with the mantle as it used to study geologically short- ascends? Lundstrom found that as the timescale processes. Using new tech- basalt interacts with the peridotite, niques of mass spectrometry, sodium and alkali elements from the Lundstrom can measure samples as basalt rapidly diffuse into the peri- small as one femtogram (10' 15 grams), dotite. The diffusion of sodium into just a few million atoms. the peridotite triggers further partial Recently, Lundstrom has been melting. Instead of 10 percent of the studying U-series isotopes in basalt solid melting at a given pressure and samples taken from mid-ocean ridges. Lundstrom now plans to move temperature, the solid melts at 20 per- is striving rate at He to understand the out of the mantle, on to the Earth's cent. So, as melt rises through peri- charac- which the mantle melts and to surface.