Research
How do geoscience departments reward faculty, staff, and students who are working to make our field more divers, equitable and inclusive?
This project aims to identify, empower, and reward diversity, equity, and inclusion (DEI) champions within the geosciences by aligning hiring, promotion, award, and other evaluation systems with goals to promote diversity and inclusion within our field. Working with with the Southwest Center for Human Relations Studies (SWCHRS), we will learn from and work with national leaders in diversity, equity, and inclusion (DEI) initiatives in higher education to revise and re-envision evaluation and reward structures within academic units that recruit and train the next generations of geoscientists. More information can be found here.
How fast do minerals react with salty water? What secondary minerals form in these environments? Can we detect evidence of high-salinity alteration on Mars and other planetary bodies?
We are working to answer these questions via mineral dissolution experiments in high salinity brines, supported by NASA. Recent publications include:
- Phillips-Lander CM, Elwood Madden AS, Hausrath EM, Elwood Madden ME. (in press) Aqueous alteration of pyroxene in sulfate, chloride, and perchlorate brines: Implications for post-Noachian aqueous alteration on Mars. GCA.
- Phillips-Lander CM, Parnell SR, McGraw LE, Elwood Madden ME (2018) Carbonate dissolution rates in high salinity brines: Implications for post-Noachian chemical weathering on Mars
- Legett C, Pritchett BN, Elwood Madden AS, Phillips-Lander CM, Elwood Madden, ME (2018). Jarosite dissolution rates in perchlorate brine, Icarus.
- Phillips-Lander CM, Legett C, Elwood Madden AS, Elwood Madden ME. (2017) Can we use pyroxene weathering textures to interpret aqueous alteration conditions? Yes and No. American Mineralogist 102, 1915-1921. 2138/am-2017-6155
- Steiner MH, Hausrath EM, Elwood Madden ME, Ehlmann BL, Olsen AA, Gainey SR (2016) Dissolution of Nontronite in Low Water Activity Brines and Implications for the Aqueous History of Mars, Geochimica et Cosmochimica Acta 195, 259-276.
- Miller, J. L., Madden, A. E., Phillips-Lander, C. M., Pritchett, B. N., & Madden, M. E. (2016). Alunite dissolution rates: Dissolution mechanisms and implications for Mars. Geochimica et Cosmochimica Acta, 172, 93-106.
- Dixon E, Elwood Madden AS, Hausrath E, Elwood Madden ME, (2015) Assessing hydrodynamic effects on jarosite dissolution rates, reaction products, and particle lifetimes, JGR-PlanetsDOI: 10.1002/2014JE004779
- Pritchett BN, Elwood Madden ME, Madden AS (2012) Jarosite dissolution rates and maximum lifetimes in high salinity brines: Implications for Earth and Mars. Earth and Planetary Science Letters, v. 357–358, 327–336.
Can we use Raman spectroscopy to measure aqueous solutes in high salinity brines? How can we apply these techniques to measure aqueous solutes remotely on other planetary bodies?
The Fall 2015 GeoWriting class developed initial calibration curves for solutes in high salinity brines. Research is ongoing to continue this investigation.
McGraw LM, McCollom NM, Phillips-Lander CM, Elwood Madden ME (2018) Measuring Sulfate and Perchlorate in High Salinity Planetary Waters using Raman Spectroscopy, ACS Earth and Space Chemistry, 2 (10), 1068-1074. DOI: 10.1021/acsearthspacechem.8b00082
What clues can we observe in fluvial sediments that will help us determine the climate in which these clastic sediments formed? Do glacially generated sediments weather differently than sediments produced in warmer climates? How does reactive surface area affect chemical weathering of primary minerals in different climates?
Through collaborations with sedimentologist Lynn Soreghan and her students, we have conducted five field studies to compare fluvial sediment textures and chemical weathering indicators under different modern climate conditions funded by NSF. Reactive surface area experiments are underway, funded by a follow-up grant from NSF.
- Joo, Y. J., Soreghan, A. M., Madden, M. E. E., & Soreghan, G. S. (2018). Quantification of particle shape by an automated image analysis system: a case study in natural sediment samples from extreme climates. Geosciences Journal, 1-8. Geosciences Journal.
- Marra K, Elwood Madden M, Soreghan G, Hall B (2017) Chemical Weathering Trends in Fine-Grained Ephemeral Stream Sediments of the McMurdo Dry Valleys, Antarctica Geopmorphology 281, 13-30.
- Marra, KR, Elwood Madden, ME, Soreghan, GS, Hall, BL (2015) BET surface area distributions in polar stream sediments: implications for silicate weathering in a cold-arid environment, Applied Geochemistry 52, 31-42.
- Marra KR, Soreghan GS, Elwood Madden ME, Keiser LJ, Hall BL (2014) Trends in Grain Size and Surface Area in Cold-Arid vs Warm Semi-Arid Fluvial Systems. Geomorphology, v. 206, 483-491.
- Stumpf AR, Elwood Madden ME, Soreghan GS, Hall BL, Keiser LJ, Marra KR (2012) Glacier meltwater stream chemistry in Wright and Taylor Valley, Antarctica: Significant roles of drift, dust, and biological processes in chemical weathering in a polar climate. Chemical Geology, 322-323, 79-90.
- Joo, Y. J., Elwood Madden, M. E., & Soreghan, G. S. (2018). Anomalously low chemical weathering in fluvial sediment of a tropical watershed (Puerto Rico). Geology, 46(8), 691-694.
- Gerilyn Soreghan, Young Ji Joo, Megan E Elwood Madden, Sarah VanDeventer (2016). Silt production as a function of climate and lithology under simulated comminution. Quaternary International.
How fast does gas react with ice to form clathrates at low temperatures? How quickly do these clathrate compounds dissociate to form ice and gas under low temperature and pressure conditions? How do gases diffuse through ice and clathrate at low temperatures?
We recently acquired a High Resolution Mapping Raman Microscope/Spectrometer to observe volatile behavior in ice and clathrates under planetary analog conditions. Recent publications include:
- Ambuehl D, Elwood Madden ME (2014) CO2 Hydrate formation and dissociation rates: Application to Mars. Icarus, v. 234, 45-52.
- Mousis O, Chassefiere E, Chevrier V, Elwood Madden ME, Lakhlifi A, Lunine JI, Montmessin F, Picaud S, Schmidt F, and Swindle TD (2013) Volatile trapping in Martian clathrates. Space Science Reviews v. 173, 213–250.
- Gainey SR and Elwood Madden ME (2012) Kinetics of Methane Clathrate Formation and Dissociation Under Mars Relevant Conditions. Icarus, 218, 513-524.
- Root MJ and Elwood Madden ME (2012) Potential Effects of Obliquity Change on Gas Hydrate Stability Zones on Mars. Icarus, 218, 534-544.
