Most of my work is aimed to better understand chemical weathering processes on Mars. However, I am also very interested in fundamental weathering processes, weathering rinds and rock coatings, soils, mineral resources and mining, impact geology, and petrology. The most exciting work always comes through collaboration...If you are interested to work together on projects that combine expertise, please contact me.
Some recent work has been focused on the analysis of Martian sulfate deposits. The origin of layered sulfate-bearing rocks on Mars remains a mystery. Infrared spectral measurements have shown layered sulfate bedrock in many locations on Mars, and one of those places, Meridiani Planum, has been explored in great detail by NASA's Opportunity Rover. The most widely accepted model to explain the origin of these sulfates (at Meridiani Planum and possibly elsewhere), is that they formed in association with a large scale playa lake-groundwater system. However, while this model provides an explanation for many of the geological characteristics of the deposits, it does not well explain extremely homogenous nature of the deposits, the bulk chemistry of basalt+SO2, and the origin extremely acidic fluids that formed the sulfates. Recently, Niles and Michalski proposed an alternative model in which the sulfates at Meridiani and possibly elsewhere, were formed within massive, low-latitude ice deposits. In this model, basaltic dust and acidic aerosols were trapped within the ice, and chemical weathering occurred within small pockets of extremely acidic solutions. After the ice sublimated and/or melted, the residual material was reworked by wind into the cross-bedded sedimentary rocks we see today. I have a recently funded MDAP grant to test this hypothesis through a global, region, and local-scale analysis of the spectroscopic and geomrophological properties of sulfate deposits on Mars. The image below shows an example of how we are reconstructing the stratigraphy of sulfate deposits with CRISM, CTX, OMEGA, and HiRISE data. Collaborators: Paul Niles, Alice Baldridge, and Melissa Lane.
Other recent work has been focused on Martian phyllosilicate deposits. Clay minerals were originally discovered on Mars using near infrared reflectance data from the Observatoire pour la Mineralogie, l'Eau, les Glaces, et l'Activité (OMEGA) (see Poulet et al. 2005). Subsequent work with OMEGA and CRISM by many authors has shown many exposures of phyllosilicates on Mars. These deposits are thought to be very important because they probably formed in association with abundant surface or subsurface water, and they may represent a time period when Mars would have been habitable to life. In my recent work, I have been using near infrared remote sensing data in combination with thermal infrared emission spectra from the TES and THEMIS instruments to gain more insight into the mineralogy of the phyllosilicates and the bulk mineralogy of the rocks where the phyllosilicates are found. Collaborators: Jean-Pierre Bibring, Francois Poulet, Nicolas Mangold, Damien Loizeau, John Carter, and Eldar Noe Dobrea.
Some of the phyllosilicate-bearing deposits are also under consideration as candidate landing sites for the upcoming Mars Science Laboratory (MSL) mission. I have been working with a large community of researchers to help decide, through open debate and scientific scrutiny, where the MSL mission should land on Mars. The image below shows the a phyllosilicate map derived from OMEGA data for the Mawrth Vallis region of Mars - one of the final remaining candidate sites. OMEGA data are draped over THEMIS daytime IR and MOLA. If you use this image, please cite it.
Michalski, J., F. Poulet, J.-P. Bibring, and N. Mangold (2009), Analysis of phyllosilicate deposits in the Nili Fossae region of Mars: Comparison of TES and OMEGA data , Icarus, doi:10.1016/j.icarus.2009.09.006
Baldridge, A. M., S. J. Hook, J. K. Crowley, G. M. Marion, J. S. Kargel, J. L. Michalski, B. J. Thomson, C. R. de Souza Filho, N. T. Bridges, and A. J. Brown (2009), Contemporaneous deposition of phyllosilicates and sulfates: Using Australian acidic saline lake deposits to describe geochemical variability on Mars, Geophys. Res. Lett., 36, L19201, doi:10.1029/2009GL040069L
Noe Dobrea E. Z., J.L. Bishop, N.K. McKeown, R. Fu, C. Rossi, C. Heinlein, V. Hanus, J. Michalski, G. Swayze, F. Poulet, J.-P. Bibring, J.F. Mustard; B.L. Ehlmann, S. Murchie, A.S. McEwen, E. Malaret, C. Hash, and the CRISM Team (in review), Mineralogy and stratigraphy of the phyllosilicate-bearing and dark mantling units in the Mawrth Vallils region of Mars: Constrains on geologic origins, J. Geophys. Res.
Niles, P. and J. Michalski (2009), Meridiani Planum sediments on Mars formed through weathering in massive ice deposits, Nature Geoscience, 2, 215 – 220.
Michalski, J. R. and R. Fergason (2009), Composition and thermal inertia of the Mawrth Vallis region of Mars from TES and THEMIS data, Icarus, 199 (1), 25-48, doi: 10.1016/j.icarus.2008.08.016
Poulet, F., N. Mangold, D. Loizeau, J.-P. Bibring, Y. Langevin, J. Michalski, and B. Gondet (2008), Abundance of minerals in the phyllosilicate-rich units on Mars, Astronomy & Astrophysics, 487, L41-L44.
Bishop, J., Noe Dobrea, E., McKeown, N., Parente, M., B. Ehlmann, J. Michalski, F. Poulet, G. Swayze, J. Mustard, S. Murchie, and J.-P. Bibring (2008), Phyllosilicate Diversity and Past Aqueous Activity Revealed at Mawrth Vallis, Mars. Science. 321 (5890), 830-833.
Michalski, J. R. and Noe, E. Z. (2007), Evidence for a sedimentary origin of clay minerals in the Mawrth Vallis region, Mars, Geology, 35 (10), 951-954.
Michalski, J. R., S. J. Reynolds, P. Niles, T. G. Sharp, and P. R. Christensen (2007), Alteration mineralogy in detachment zones: Insights from Swansea, Arizona., Geosphere., 3 (4), 184- 198.
Clark, B., R. Arvidson , R. Gellert , R. Morris , D. Ming , L. Richter , S. Ruff , J. Michalski , W. Farrand , A. S. Yen , K. Herkenhoff , R. Li , S. W. Squyres , C. Schroeder , G. Klingelhoefer J. F. Bell III. (2007), Evidence for montmorillonite or its compositional equivalent in Columbia Hills, Mars, J. Geophys. Res., 112, E06S01, doi:10.1029/2006JE002756
Ruff, S. W., P. Christensen , D. Blaney , W. H. Farrand , J. Johnson , J. Michalski , J. E. Moersch, S. Wright , S. W. Squyres (2006), The rocks of Gusev Crater as viewed by the Mini-TES instrument, J. Geophys. Res., 111(E12), doi: 10.1029/2006JE002747.
Michalski, J. R., M. D. Kraft, T. G. Sharp, P. R. Christensen (2006), Effects of chemical weathering on infrared spectra of Columbia River Basalt and spectral interpretation of martian alteration, EPSL, 284 (3-4), 822-829.
Michalski, J. R., M. D. Kraft, T. G. Sharp, L. B. Williams, and P. R. Christensen (2006), Emission spectroscopy of clay minerals and evidence for poorly crystalline aluminosilicates on Mars from TES data, J. Geophys. Res.,111, E03004, doi:10.1029/2005JE002438.
Hurowitz, J., S. S. McLennan, N. Tosca, R. Arvidson, J. R. Michalski, D. Ming., C. Shroeder, and S. Squyres (2006), In-situ and experimental evidence for acid weathering of rock and soils on Mars, J. Geophys. Res., 111 (E2), E02S19.
Michalski, J. R., M. D. Kraft, T. G. Sharp, L. B. Williams, and P. R. Christensen (2005), Mineralogical constraints on the high-silica Martian surface component observed by TES, Icarus, 174, 161-177.
Michalski, J. R., S. J. Reynolds, P. R. Christensen, and T. G. Sharp (2004), Thermal infrared analysis of weathered granitic rock compositions in the Sacaton Mountains, Arizona: Implications for petrologic classifications from thermal infrared remote-sensing data, J. Geophys. Res., 109, E03007, doi:10.1029/2003JE002197.
Kraft, M. D., J. R. Michalski, and T. G. Sharp (2003), Effects of pure silica coatings on thermal emission spectra of basaltic rocks: Considerations for Martian surface mineralogy, Geophys. Res. Lett. 30 (24), 2288, doi: 10.1029/2003GL018848.
Michalski, J. R., M. D. Kraft, T. Diedrich, T. G. Sharp, and P. R. Christensen (2003), Thermal emission spectroscopy of the silica polymorphs and considerations for the remote sensing of Mars, Geophys. Res. Lett., 30 (19) 2008, doi: 10.1029/2003GL018354.
Michalski, J. R. and R. Greeley (2002), En echelon ridge and trough structures on Europa, Geophys. Res. Lett., 29 (10), 10.1029/2002GL014956.
