Welcome to GeoUnion, the graduate student body of the Department of Earth, Environmental and Planetary Sciences. GeoUnion strives to supplement the overall graduate student experience at Rice and DEEPS. GeoUnion represents DEEPS in the overall Rice grad student community, acts as a liaison between students and faculty and organizes a number of intra- and inter-departmental events throughout the academic year.
– JANUARY 31, 2020
Fed grant backs Rice earthquake research
HOUSTON – (Jan. 31, 2020) – Rice University geologist Melodie French is crushing it in her quest to understand the physics responsible for earthquakes.
The assistant professor of Earth, environmental and planetary science has earned a prestigious CAREER Award, a five-year National Science Foundation (NSF) grant for $600,000 to support her investigation of the tectonic roots of earthquakes and tsunamis.
CAREER awards support the research and educational development of young scholars likely to become leaders in their fields. The grants, among the most competitive awarded by the NSF, go to fewer than 400 scholars each year across all disciplines.
For French, the award gives her Rice lab the opportunity to study rocks exhumed from subduction zones at plate boundaries that are often the source of megathrust earthquakes and tsunamis. Her lab squeezes rock samples to characterize the strength of the rocks deep underground where the plates meet.
“Fundamentally, we hope to learn how the material properties of the rocks themselves control where earthquakes happen, how big one might become, what causes an earthquake to sometimes arrest after only a small amount of slip or what allows some to grow quite large,” French said.
“A lot of geophysics involves putting out instruments to see signals that propagate to the Earth’s surface,” she said. “But we try to understand the properties of the rocks that allow these different phenomena to happen.”
That generally involves putting rocks under extreme stress. “We squish rocks at different temperatures and pressures and at different rates while measuring force and strain in as many dimensions as we can,” French said. “That gives us a full picture of how the rocks deform under different conditions.”
The lab conducts experiments on both exposed surface rocks that were once deep within subduction zones and rock acquired by drilling for core samples.
“I’m working with (Rice Professor) Juli Morgan on a subduction zone off of New Zealand where they drilled through part of the fault zone and brought rock up from about 500 meters deep,” French said. “But many big earthquakes happen much deeper than we could ever drill. So we need to go into the field to find ancient subduction rocks that have somehow managed to come to the surface.”
French is not sure if it will ever be possible to accurately predict earthquakes. “But one thing we can do is create better hazard maps to help us understand what regions should be prepared for quakes,” she said.
French is a native of Maine who earned her bachelor’s degree at Oberlin College, a master’s at the University of Wisconsin-Madison and a Ph.D. at Texas A&M University.
The award, co-funded by the NSF’s Geophysics, Tectonics and Marine Geology and Geophysics programs, will also provide inquiry-based educational opportunities in scientific instrument design and use to K-12 students as well as undergraduate and graduate-level students.
Read the award abstract at https://www.nsf.gov/awardsearch/showAward?AWD_ID=1945264&HistoricalAwards=false.
Follow Rice News and Media Relations via Twitter @RiceUNews.
Rheology and Deformation (French Lab): https://mefrench.com and the latest issue of Outcroppings- https://earthscience.rice.edu/wp-content/uploads/2020/02/French-lab-spread.pdf
An interview with Melodie French: http://earthscience.rice.edu/wp-content/uploads/2016/09/2016-Outcroppings-MelodieFrench.pdf
Earth, Environmental and Planetary Sciences: https://earthscience.rice.edu
Wiess School of Natural Sciences: https://naturalsciences.rice.edu
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation’s top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice’s undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 4 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger’s Personal Finance.
Much of the world’s economic copper resources are hosted in porphyry copper deposits (PCDs), shallow level magmatic intrusions associated mostly with thick () magmatic arcs, such as mature island arcs and continental arcs. However, a well-known, but unresolved paradox, is that arc magmas traversing thick crust, particularly in continental arcs, are generally depleted in Cu whereas in island arcs, where PCDs are less common, magmas become enriched in Cu. Here, we show that the formation of PCDs requires a complex sequence of intra-crustal magmatic processes, from the lower crust to the upper crust. PCDs form when the crust becomes thick () enough to crystallize garnet. Garnet fractionation depletes Fe from the magma, which drives sulfide segregation and removal of most of the magma’s Cu into the lower crust, leaving only small amounts of Cu in the residual magma to make PCDs. However, because garnet is depleted in ferric iron, the remaining Fe in the magma becomes progressively oxidized, which eventually oxidizes sulfide to sulfate, thereby releasing sulfide bound Cu from the magma into solution. This auto-oxidation of the magma, made possible by deep-seated garnet fractionation, increases the ability of endogenic magmatic fluids to self-scavenge Cu from large volumes of otherwise Cu-poor magmas and then transport and concentrate Cu to the tops of magmatic bodies. Examination of the occurrence of PCDs in the central Andes shows that ore formation occurs when continental arcs reach their maximum thickness (), just before the termination of magmatism.
Cin-Ty A.Lee and MingTang, Volume 529, 1 January 2020, 115868
Gabor Tari is the recipient of the Vlastimila “Vlasta” Dvořáková International Ambassador Service Award. This award is given to those who have promoted growth and awareness of the AAPG organization internationally, outside the United States, and created opportunities for the Association to reach a wider audience of geoscientists worldwide. Tari is being honored for exception role in being the main driver of catalysts for many international events in the Europe Region.
AAPG awards, approved by the Executive Committee, are presented annually to recognize individuals for service to the profession, the science, the Association and the public.
Biographies and citations of all award winners will be included in a future AAPG BULLETIN. (Image courtesy of AAPG)
Gabor Tari received his Ph.D. from Rice in 1994. He lives in Austria and is the Group Chief Scientist for Geology at OMV Exploration and Production Company.
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