Justin Filiberto | Geology | SIU

Southern Illinois University



College of Science


Assistant Professor

Office: 203 Parkinson Lab
Phone: 618-453-4849
E-mail: filiberto@siu.edu

Research Interests:

My research focuses on mineralogic and petrologic investigations into basalt formation in order to constrain crustal and mantle evolution. I combine detailed mineralogy and petrology of basalts with high-temperature, elevated-pressure experiments to understand how basalts formed and crystallized. 

My research focuses on 4 main topics: 1) constrain the depth and thermal vigor of melting in the martian mantle, 2) investigate the effect of halogens on basalt genesis, 3) understand the origin of the Martian olivine-phyric shergottite meteorites and 4) investigate potential magnetic anomalies in the terrestrial upper mantle and lower crust.

1). My recent work has focused on understanding the mantle potential temperature and cooling history of Mars and the similarities and differences with the Earth (Filiberto et al., 2010; Filiberto and Dasgupta 2011; Filiberto and Dasgupta submitted). This work has shown that an average mantle potential temperature of 1450±80 °C may represent a global average for the martian mantle during the Noachian (ancient Mars). If we compare this estimate of ancient martian mantle potential temperature with the terrestrial mantle potential temperatures based on Archean komatiites [≥1700 °C; (Lee et al., 2010)], this suggests that the martian mantle was actually significantly colder than the terrestrial mantle. The TP estimates for the Hesperian and Amazonian, based on orbital analyses of the crust, are lower in temperature than these estimates for the Noachian which is consistent with simple convective cooling of the interior of Mars. The TP estimates of from the martian meteorites are significantly higher than estimates based on older rocks. This suggests that the martian meteorites represent localized thermal anomalies and they may not represent a global estimate for the basaltic magmas on Mars. Future directions for this project include partial melting experiments on the Martian mantle to produce surface basalts and meteorites; further modeling of mantle potential temperatures based on surface basalts and meteorites; and combing previous and ongoing studies to investigate the cooling history of terrestrial planetary interiors.

2) I have investigated the effects of chlorine and fluorine on liquidus and crystallization behavior of a Fe-rich magma composition (Filiberto and Treiman 2009 a,b; Filiberto et al. 2012; Filiberto et al. 2014). My results have shown that Cl complexes in the melt with Fe, and perhaps Mg and Ca, causing an increase in the Si-activity and stabilizing pyroxene with respect to olivine. By complexing with cations, Cl has a large effect depressing liquidus and ol-pyx-melt multiple saturation point. Therefore, small amounts of dissolved chlorine will enable basalts to be produced at lower pressures and temperatures. The F-bearing experimental results show that F depresses the basalt liquidus, extends the pyroxene stability field to lower pressure, and forces the liquidus phases to be more Fe-rich. Mineral-melt Fe2+-Mg KD calculated for both pyroxenes and olivines increase with increasing F content of the melt. Therefore, we infer that F complexes with Mg in the melt and thus increases the melt’s silica activity, depresses the liquidus, and changes the composition of the crystallizing minerals.

3). Olivine-phyric shergottites have been recognized as a significant and important subgroup of the Martian shergottites. Their relatively high bulk rock and olivine core Mg#s suggests that they could represent primitive melts, i.e., unfractionated liquids formed by direct partial melting of the mantle. My recent work has focused on experimental and petrologic studies of olivine-phyric shergottites NWA 1068, NWA 5789 and an ongoing study of NWA 6234. I have also been investigating Fe-Mg partitioning between olivine and Fe-rich Martian magmas with applications to the amount of olivine accumulation in the olivine-phyric shergottites. 

4). The combined petrology, structural geology, and geopghysics groups at SIU have recently been funded through NSF Geophysics to investigate potential magnetic anomalies in the terrestrial upper mantle. This work will involve decompression experiments from mantle to crustal pressures and temperatures, to investigate if decompression alone can produce a magnetic anomaly that is commonly seen in mantle xenoliths (Ferré et al. 2013). Combined with the high pressure decompression experiments, will be high temperature oxidation experiments. It has been known that oxidation of olivine at high temperature can produce magnetite through oxidation of the iron in the olivine structure (Kohlstedt et al. 1976; olivine decoration experiments). However, we will combine similar experiments with magnetic measurements and compare these results with the mineralogy and magnetic measurements of mantle xenoliths, as well as the location of magnetite grains in these natural samples. The overall goal of this work is to revisit the non-magnetic mantle paradigm and, if need be, to propose a new model in which the uppermost mantle is characterized by different magnetic properties in different tectonic settings.

Selected Recent Publications

J. Filiberto, A.H. Treiman, P.A. Giesting#, C.A. Goodrich, and J. Gross (2014) High-Temperature Chlorine-Rich Fluid in the Martian Crust: A Precursor to Habitability. Earth and Planetary Science Letters 401, 110-115.

J. Filiberto, J. Gross, J. Trela, and E.C. Ferré (2014) Gabbroic Shergottite Northwest Africa 6963: an intrusive, crustal sample of Mars. American Mineralogist 99, 601-606.

J. Filiberto (2014) Magmatic diversity on Venus: Constraints from terrestrial analog crystallization experiments. Icarus 231, 131-136.

P. Giesting and J. Filiberto (2014) Quantitative models linking igneous amphibole composition with magma volatile chemistry. American Mineralogist 99, 852-865.

J. Filiberto, E. Chin, J.M.D. Day, I.A. Franchi, J. Gross, R.C. Greenwood, S. Penniston-Dorland, S.P. Schwenzer, and A.H. Treiman (2012) Geochemistry of Intermediate Olivine-Phyric Shergottite NorthWest Africa 6234 with Similarities to Basaltic Shergottite NorthWest Africa 480 and Olivine-Phyric Shergottite NorthWest Africa 2990. Meteoritics and Planetary Science 47(8): 1256-1273.

J. Filiberto and R. Dasgupta (2011) Fe2+-Mg partitioning between olivine and martian magmas: application to genesis of olivine-phyric shergottites and conditions of melting in the Martian interior. Earth and Planetary Science Letters 304(3-4):527-537.


GEOL 315 - Igneous and Metamorphic Petrology
GEOL 411 - Volcanology
GEOL 430 - Planetary Geology
GEOL 520 - Advanced Topics: Igneous and Metamorphic Petrology