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Kenneth Williford

Photo of Kenneth Williford


4800 Oak Grove Drive
M/S 183-301

Pasadena, CA 91109

Curriculum Vitae:

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Member of:

Astrobiology and Ocean Worlds


Ken Williford serves as the Deputy Project Scientist for the NASA Mars 2020 mission, and is the director of the JPL Astrobiogeochemistry Laboratory (abcLab). Research in the abcLab is broadly concerned with tracing the flow of biologically important elements (e.g. C, H, O, N, S) through Earth systems. To do this, we use the tools of "biogeochemistry" - uncovering the chemical traces of life (bio) preserved in Earth materials (geo) - within the context of astrobiology (the search for life on other planets). In recent years, Williford has focused on developing analytical techniques to search for signs of life and environment in some of the oldest rocks on Earth. Fossils are very rare in these rocks, and those that do exist are almost always microscopic. In the abcLab at JPL, Ken studies the biogeochemistry of ancient Earth rocks in part to understand how we can apply similar techniques to the search for evidence of life on other planets - in rocks returned to Earth from the surface of Mars, for example.

The JPL abcLab features capabilities for bulk geochemistry as well as spatially resolved, in situ analytical techniques. The lab features a gas chromatograph-mass spectrometer-isotope ratio mass spectrometer (GC-MS-irMS) system with EA (elemental analyzer), capable of bulk carbon and nitrogen isotope analysis of organic matter, bulk sulfur isotope analysis of sulfides, and on-line structural and compound specific hydrogen or carbon isotope analysis of individual organic compounds. A vacuum extraction line and high temperature conversion elemental analyzer (TC/EA) enables bulk hydrogen and oxygen isotopic analysis of organic matter and hydrous minerals. Our light and electron microscopy facility is used for micropaleontology and petrographic analysis supporting spatially resolved, microanalytical techniques including SIMS. The abcLab is part of the JPL Center for Analysis of Returned Samples (CARS), a cooperative joint facility that enables clean sample preparation and curation, microscopic characterization, and geochemical analysis of ancient terrestrial and extraterrestrial materials.


  • Ph.D. Earth and Space Sciences and Astrobiology, University of Washington, Seattle, Washington (2007)
  • M.S. Geological Sciences, University of Washington, Seattle, Washington (2000)
  • B.S. Natural Resources, University of the South, Sewanee, Tennessee (1998)

Professional Experience

  • Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA (2012 - Present)
    • Deputy Project Scientist, NASA Mars 2020 mission (2014 - Present)
    • Research Scientist, Planetary Chemistry and Astrobiology (2012 - Present)
    • Research Scientist, Mars Science Laboratory and Mars 2020 Sample Handling Group (2013 - Present)
  • Research Associate, Department of Geoscience, University of Wisconsin, Madison, WI USA (2010 - 2012)
  • Research Associate, Department of Chemistry, Curtin University, Perth, WA Australia (2007 - 2010)
  • IGERT Fellow, Department of Earth and Space Sciences, University of Washington, Seattle, WA USA (2005 - 2007)
  • Research Assistant, Department of Earth and Space Sciences, University of Washington, Seattle, WA USA (2003 - 2005)

Community Service

  • Imagine Mars, Akira Toki Middle School, Madison, WI (2011)
  • Astrobiology in Your Back Yard, Madison, WI (2011)
  • Astrobiology night at the ballpark, Madison, WI (2010)
  • Bottle Biology, University of Wisconsin (2010 - 2012)
  • Field trip to stromatolites of the Strelley Pool Formation with the high school students of Marble Bar, Western Australia (2008)
  • Discover Smoke Farm: a BioBlitz and celebration of biodiversity in the foothills of the Cascade mountains with students from Seattle, WA

Research Interests


    • Archean biosignatures: using detailed petrography and in situ measurements of the elemental and isotopic composition of organic matter and biominerals to resolve ambiguity in the search for evidence of life on the early Earth
    • Microfossils and microbial metabolism: measuring the elemental, molecular, and isotopic composition of fossilized microorganisms to understand microbial metabolism and biosignature preservation
    • Atmospheric oxygenation: using in situ and bulk measurements of carbon and multiple sulfur isotopes to understand changes in the concentration of oxygen in Earth's atmosphere
    • Mass extinctions: understanding the behavior of biogeochemical cycles during the collapse and recovery of the biosphere associated with mass extinction events

Selected Awards

  • NSF IGERT Astrobiology Fellowship (2005 - 2007)

Selected Publications

1.      Alleon, J., Flannery, D.T., Ferralis, N., Williford, K.H., Zhang, Y., Schuessler, J.A., Summons, R.E., 2019. Organo-mineral associations in chert of the 3.5 Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments. Scientific Reports 9: 16712 (

2.      Caudill, C.M., Osinski, G.R., Pilles, E., Sapers, H.M., Pontefract, A.J., Francis, R., Duff, S., Laughton, J., O’Callaghan, J., Sopoco, R., Tolometti, G., Tuite, M., Williford, K.H., Xie, T.Q., 2019. Field and laboratory validation of remote rover operations Science Team findings: The CanMars Sample Return analogue mission. Planetary and Space Science 176: 104682. (

3.      Tuite, M.L., Williford, K.H., Macko, S.A., 2019. From greenhouse to icehouse: Nitrogen biogeochemistry of an epeiric sea in the context of the oxygenation of the Late Devonian atmosphere/ocean system. Palaeogeography, Palaeoclimatology, Palaeoecology 531: 109204 (

4.      Flannery, D., Allwood, A., Hodyss, R., Summons, R., Tuite, M., Walter., M., Williford, K., 2019. Microbially-influenced formation of Neoarchean ooids. Geobiology 17 151-160 (

5.      DiLoreto, Z.A., Bontognali, T.R.R., Al Disi, Z.A., Al Saad Al-Kuwari, H., Williford, K.H., Strohmenger, C.J., Sadooni, F., Palermo, C., Rivers, J.M., McKenzie, J.A., Tuite, M., Dittrich, M., 2019. Microbial community composition and dolomite formation in the hypersaline microbial mats of the Khor Al-Adaid sabkhas, Qatar. Extremophiles (

6.      Osinski, G.R. et al., 2019. The CanMars Mars Sample Return Analogue Mission. Planetary and Space Science 166: 110-130 (

7.      Abbey, W., R. Anderson, L. Beegle, J. Hurowitz, K.H. Williford, G. Peters, J.M. Morookian, C. Collins, J. Feldman, R. Kinnett, L. Jandura, D. Limonadi, C. Logan, S. McCloskey, J. Melko, A. Okon, M. Robinson, C. Roumeliotis, C. Seybold, J. Singer, and N. Warner, 2019. A look back: The drilling campaign of the Curiosity rover during the Mars Science Laboratory’s Prime Mission. Icarus 319:1-13 (

8.      Pilles, E.A., Cross, M., Caudill, C.M., Francis, R., Osinski, G.R., Newman, J., Battler, M., Bourassa, M., Haltigin, T., Hipkin, V., Kerrigan, M., McLennan, S., Silber, E.A., Williford, K., 2019. Exploring new models for improving planetary rover operations efficiency through the 2016 CanMars Mars Sample Return (MSR) analogue deployment. Planetary and Space Science 165: 250-259 (

9.      Manning-Berg, A.R., Wood, R.S., Williford, K.H., Czaja, A.D., Kah, L.C., 2019. The taphonomy of Proterozoic microbial mats and implications for early diagenetic silicification. Geosciences 9: 40 (

10.     Lepot, K., Williford, K.H., Philippot, P., Thomazo, C., Ushikubo, T., Kitajima, K., Mostefaoui, S., Valley, J.W., 2019. Extreme 13C-depletions and organic sulfur content argue for S-fueled anaerobic methane oxidation in 2.72 Ga old stromatolites. Geochimica et Cosmochimica Acta 244: 522-547 (

11.     Williford, K.H., K.A. Farley, K.M. Stack, A.C. Allwood, D. Beaty, L. Beegle, R. Bhartia, A.J. Brown, M. de la Torre Juarez, S.-E Hamran, M.H. Hecht, J. Hurowitz, J.A. Rodriguez-Manfredi, S. Maurice, S. Milkovich, R.C. Wiens, 2018. The NASA Mars 2020 rover mission and the search for extraterrestrial life. In: From Habitability to Life on Mars, Cabrol, N.A., and E.A. Grin, eds., p. 275-308, Elsevier (

12.     Grant, J., Golombek, M., Wilson, S., Farley, K., Williford, K., Chen, A., 2018. The science process for selecting the landing site for the 2020 Mars rover. Planetary and Space Science 164: 106-126 (

13.     Finstad, K.M., Pfeiffer, M., McNicol, G., Tuite, M., Williford, K.H., Amundson, R., 2018. A late Quaternary paleoenvironmental record in sand dunes of the northern Atacama Desert, Chile. Quaternary Research 90: 127-138 (

14.     Ishida, A., Kitajima, K., Williford, K.H., Tuite, M.L., Kakegawa, T., Valley, J.W., 2018. Simultaneous in situ analysis of carbon and nitrogen isotope ratios in organic matter by secondary ion mass spectrometry Geostandards and Geoanalytical Research 42: 189-203. (

15.     McMahon, S., Bosak, T., Grotzinger, J., Milliken, R., Summons, R., Daye, M., Newman, S., Fraeman, A., Williford, K.H., Briggs, D., 2018. A field guide to finding fossils on Mars. Journal of Geophysical Research: Planets 123: 1012-1040 (

16.     Flannery, D., Allwood, A.C., Summons, R.E., Williford, K.H., Abbey, W., Matys, E.D., Ferralis, N., 2018. Spatially-resolved isotopic study of carbon trapped in ~3.43 Ga Strelley Pool Formation stromatolites. Geochemica et Cosmochimica Acta 223: 21-35. (

17.     Schopf, J.W., Kudryavstev, A.B., Osterhout, J.T., Williford, K.H., Kitajima, K., Valley, J.W., Sugitani, K., 2017. An aerobic similar to 3400 Ma shallow-water microbial consortium: Presumptive evidence of Earth’s Paleoarchean anoxic atmosphere. Precambrian Research 299: 309-318 (

18.     Abbey, W.J., Bhartia, R., Beegle, L.W., DeFlores, L., Paez, V., Sijapati, K., Williford, K., Tuite, M., Hug, W., Reid, R., 2017. Deep UV Raman spectroscopy for planetary exploration: The search for in situ organics. Icarus 290: 201-214 (

19.     Izon, G., Zerkle, A.L., Williford, K.H., Farquhar, J., Poulton, S.W., Claire, M.W., 2017. Biologic regulation of atmospheric chemistry en route to planetary oxygenation. Proceedings of the National Academy of Sciences of the United States of America 114: E2571-2579 (

20.     Stack, K.M., Edwards, C.M., Grotzinger, J.P., Gupta, S., Sumner, D.Y., Calef, F.J. III, Edgar, L.A., Edgett, K.S., Fraeman, A.A., Jacob, S.R., Le Deit, L., Lewis, K.W., Rice, M.S., Rubin, D., Williams, R.M.E., Williford, K.H., 2016. Comparing orbiter and rover image-based mapping of an ancient sedimentary environment, Aeolis Palus, Gale Crater, Mars. Icarus 280: 3-21 ( 21.     Schoepfer, S.D., Algeo, T.J., Ward, P.D., Williford, K.H., Haggart, J.W., 2016. Testing the limits in a greenhouse ocean: Did low nitrogen availability limit marine productivity during the end-Triassic mass extinction? EPSL 451: 138-148 (

22.     Haddad, E.E., Tuite, M.L., Martinez, A.M., Williford, K.H., Boyer, D.L., Droser, M.L., Love, G.D., 2016. Lipid biomarker stratigraphic records through the Late Devonian Frasnian/Famennian boundary: Comparison of high- and low-latitude epicontinental marine settings. Organic Geochemistry 98: 38-53 (

23.     Tuite, M.L., Flannery, D.T., Williford, K.H., 2016. Organic geochemistry of a high-latitude Lower Cretaceous lacustrine sediment sample from the Koonwarra Fossil Beds, South Gippsland, Victoria, Australia. Memoirs of Museum Victoria 74: 73-79. (

24.     Morag, N., Williford, K.H., Kitajima, K., Philippot, P., Van Kranendonk, M.J., Lepot, K., Thomazo, C., Valley, J.W., 2016. Microstructure-specific carbon isotopic signatures of organic matter from ~3.5 Ga cherts of the Pilbara Craton support a biologic origin. Precambrian Research 275: 429-449 (

25.     Williford, K.H., Ushikubo, T., Lepot, K., Kitajima, K., Hallmann, C., Spicuzza, M.J., Kozdon, R., Eigenbrode, J.L., Summons, R.E., Valley, J.W., 2016. Carbon and sulfur isotopic signatures of ancient life and environment at the microbial scale: Neoarchean shales and carbonates. Geobiology 14: 105-128 (

26.     Schopf, J.W., Kudryavstev, A.B., Walter, M.R., Van Kranendonk, M.J., Williford, K.H., Kozdon, R., Valley, J.W., Gallardo, V.A., Espinoza, C., Flannery, D.T., 2015. Reply to Dvorak et al.: Apparent evolutionary stasis of ancient subseafloor sulfur cycling biocoenoses. Proceedings of the National Academy of Sciences of the United States of America 112: E2560 (

27.     Kasprak, A.H., Sepúlveda, J., Price-Waldman, R., Williford, K.H., Schoepfer, S.D., Haggart. J.W., Ward, P.D., Summons, R.E., Whiteside, J.H., 2015. Episodic photic zone euxinia in the northeastern Panthalassic Ocean during the end-Triassic extinction. Geology 43: 307-310 (

28.     Schopf, J.W., Kudryavstev, A.B., Walter, M.R., Van Kranendonk, M.J., Williford, K.H., Kozdon, R., Valley, J.W., Gallardo, V.A., Espinoza, C., Flannery, D.T., 2015. A fossil sulfur-cycling microbiota from the 1.8 Ga Duck Creek Formation provides promising evidence of evolution's null hypothesis. Proceedings of the National Academy of Sciences of the United States of America 112: 2087-2092 (

29.     Mahaffy, P.R. (and 26 others), 2015. The imprint of atmospheric evolution in the D/H of Hesperian clay minerals on Mars. Science 347: 412-414 (

30.     Ushikubo, T., Williford, K.H., Farquhar, J., Johnston, D.T., Van Kranendonk, M.J., Valley, J.W., 2014. Development of in situ sulfur four-isotope analysis with multiple Faraday cup detectors by SIMS and application to pyrite grains in a Paleoproterozoic glaciogenic sandstone. Chemical Geology 383: 86-99 (

31.     Williford, K.H., Grice, K., Holman, A., McElwain, J., 2014. An organic record of terrestrial ecosystem collapse and recovery at the Triassic–Jurassic boundary in East Greenland. Geochimica et Cosmochimica Acta 127: 251-263 (

32.     Farley, K.A. (and 33 others), 2013. In situ radiometric and exposure age dating of the martian surface. Science 343: published online 9 December 2013 (

33.     Lepot, K., Williford, K.H., Ushikubo, T., Sugitani, K., Mimura, K., Spicuzza, M.J., Valley, J.W., 2013. Texture-specific isotopic compositions in 3.4 Gyr old organic matter support selective preservation in cell-like structures. Geochemica et Cosmochemica Acta 112: 66-86 (

34.     Williford, K.H., Ushikubo, T., Schopf, J.W., Lepot, K., Kitajima, K., Valley, J.W., 2013. Preservation and detection of microstructural and taxonomic correlations in the carbon isotopic compositions of individual Precambrian microfossils. Geochimica et Cosmochimica Acta 104: 165-182 (

35.     Williford, K.H., Van Kranendonk, M.J., Ushikubo, T., Kozdon, R., Valley, J.W., 2011. Constraining atmospheric oxygen and seawater sulfate concentrations during Paleoproterozoic glaciation: in situ sulfur three-isotope microanalysis of pyrite from the Turee Creek Group, Western Australia. Geochimica et Cosmochimica Acta 75: 5686-5705 (

36.     Aboglila, S., Grice, K., Trinajstic, K., Snape, C., Williford, K.H., 2011. The significance of 24-norcholestanes, 4-methylsteranes and dinosteranes in oils and source-rocks from East Sirte Basin (Libya). Applied Geochemistry 26: 1694-1705 (

37.     Williford, K.H., Grice, K., Logan, G.A., Chen, J., Huston, D., 2011. The molecular and isotopic effects of hydrothermal alteration of organic matter in the Paleoproterozoic McArthur River Pb/Zn/Ag ore deposit. Earth and Planetary Science Letters 301:382-392 (

38.     Aboglila, S., Grice, K., Dawson, D., Williford, K.H., 2010. Use of biomarker distributions and compound specific isotopes of carbon and hydrogen to delineate hydrocarbon characteristics in the East Sirte Basin (Libya). Organic Geochemistry 41:1249-1258 (

39.     Zonneveld, J.P., Beatty, T.W., Williford, K.H., Orchard, M.J., McRoberts, C.A., 2010. Stratigraphy and sedimentology of the lower Black Bear Ridge section, British Columbia: candidate for the base-Norian GSSP. Stratigraphy 7(1): 61-82.

40.     Grice, K., Lu, H. Atahan, P., Asif, M., Hallmann, C., Greenwood, P., Maslen, E., Tulipani, S., Williford, K.H., Dodson, J., 2009. New insights into the origin of perylene in geological samples. Geochimica et Cosmochimica Acta 73(21): 6531-6543 (

41.     Williford, K.H., Foriel, J., Ward, P.D., Steig, E.J., 2009. Major perturbation in sulfur cycling at the Triassic/Jurassic boundary. Geology 37(9): 835-838 (

42.     Ward, P., McRoberts, C., Williford, K. Reply to comment on: “The organic carbon isotopic and paleontological record across the Triassic-Jurassic boundary at the candidate GSSP section at Ferguson Hill, Muller Canyon, Nevada, USA” by Ward et al. (2007). Palaeogeography, Palaeoclimatology, Palaeoecology 273(1-2): 205-206 (

43.     Ward, P.D., Garrison, G.H., Williford, K.H., Kring, D., Goodwin, D., Beattie, M., McRoberts, C., 2007. The organic carbon isotopic and paleontological record across the Triassic-Jurassic boundary at the candidate GSSP section at Ferguson Hill, Muller Canyon, Nevada, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 244(1-4): 281-289 (

44.     Williford, K.H., Ward, P.D., Garrison, G.H., Buick, R., 2007. An extended stable organic carbon isotope record across the Triassic-Jurassic boundary in the Queen Charlotte Islands, British Columbia, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 244(1-4): 290-296 (