Grad student wins award for meteorite research
Greg Brennecka, a graduate student in ASU’s School of Earth and Space Exploration, has been awarded the prestigious 2009 Nininger Meteorite Award, which recognizes outstanding student achievement in the “Science of Meteoritics” as embodied by an original research paper. Brennecka is the fifth ASU student to receive the Nininger Meteorite Award since the national competition’s inception in 1961.
Nininger Meteorite Award recipients are selected based on a recent research paper and a letter of support from the student’s adviser. A national panel of judges recognized his paper, “238U/235U Variations in Meteorites: Extant 247Cm and Implications for Pb-Pb dating,” published in Science in January of this year, for its high quality and its impact on the field of meteoritics.
Brennecka and colleagues at ASU (including Ariel Anbar and Meenakshi Wadhwa, professors, and Philip Janney, associate research scientist) and at the University of Frankfurt, Germany, measured the 238U/235U ratio in the earliest-formed solids in the Solar System, calcium-aluminum-rich inclusions (CAIs), the ages of which are used to define the time of Solar System formation. High-precision data obtained on CAIs of the Allende meteorite demonstrated that the 238U/235U ratio is not the same in all CAIs. The Pb-Pb dating technique has been applied for decades under the assumption that the present-day ratio of the 238U and 235U isotopes is constant in the Solar System.
The measured deviations from this assumed value imply that the calculated Pb-Pb ages of CAIs using this value could be inaccurate by as much as several million years. Although this is a small fraction of the 4.57 billion year age of the Solar System, it is significant since some of the most important events that shaped the Solar System occurred within the first 10 million years of its formation.
“Greg’s work stands as one of the more significant results in the field of cosmochemistry in recent years," wrote Wadhwa in a letter supporting Brennecka. "It obviously has important ramifications for one of the most precise absolute age dating techniques in geochemistry. Moreover, with the discovery of evidence for live 247Cm, it also has implications for the astrophysical environment in which our Solar System was born.”
Brennecka received a $1,000 scholarship and an engraved plaque. Previous recipients include: William R. Kelly 1972-73, Lindsay P. Keller 1987-88, Don D. Eisenhour 1992-93, and Nicolas Ouellette 2006-07.
Although not awarded every year, Honorable Mention went to Niina Jamsja, an undergraduate at Portland State University. Her entry, “Unusual Igneous Textures and Pentlandite in a Meteorite of LL-Chondrite Parentage, NWA 4859,” was the result of research conducted with her advisor Assistant Professor Alex Ruzicka. The selection committee recognized that, as an undergraduate, Jamsja’s work represented a high level of research.
In 1965, H.H. Nininger and Addie D. Nininger endowed the Nininger Science of Meteoritics Fund to the Center for Meteorite Studies at ASU in order to promote interest in meteorite-related topics among young scientists. The fund supports the Nininger Meteorite Award, which has been given out since 1961. The core of the meteorite collection was purchased by ASU from Nininger, and led to the establishment of the Center for Meteorite Studies in 1960.