University of California, Riverside

Earth Sciences

Department of Earth Sciences

Timothy Lyons

Timothy Lyons

Distinguished Professor of Biogeochemistry

Ph.D. Geology Geochemistry, Yale University
M.Phil. Geology, Yale University
M.S. Geology, University of Arizona
B.S. Geological Engineering, Colorado School of Mines

Specialty: Sedimentary Geochemistry, Biogeochemical Cycles, Astrobiology

Phone: (951) 827-3106
Fax: (951) 827-4324
Office: Geology 1216

Research Interests:

Much of my current work explores the evolving ocean and atmosphere and their cause-and-effect relationships with the origin and evolution of life. Biogeochemical processes that dominate modern and ancient carbonate platforms and oxygen-deficient marine basins are at the heart of this research. Primary methodologies track the signals of microbially mediated cycling of carbon, sulfur, and metals as expressed in their signature isotopic compositions preserved in ancient sedimentary rocks. With my students and colleagues, I am calibrating these proxy methods using modern sediments from the Black Sea, Cariaco Basin in Venezuela, Florida Bay, cold seeps in the Gulf of Mexico, and other settings. We have applied these proxies to deconstruct the paleoenvironmental contexts of Paleozoic black shale deposition and Precambrian biospheric evolution. Particularly exciting are patterns of early atmospheric oxygenation expressed in trace sulfate trapped within carbonate rocks (carbonate-associated sulfate) and in redox-sensitive metals within shales. Related work features marine oxygen isotope records preserved in phosphatic conodonts, iron paleoredox proxies, sulfur geomicrobiology, pathways of metal enrichment, and organic biomarker approaches.

Current Projects and Research Opportunities:

As team leader of one of the newest science teams selected to join the NASA Astrobiology Institute (NAI), much of my current research focuses on astrobiology. Our team, which involves 19 scientists from 11 institutions, has been awarded nearly $8 million over 5 years to answer these unifying questions: How has Earth remained persistently inhabited through most of its dynamic history, and how do those varying states of inhabitation manifest in the atmosphere? How might that perspective inform our search for life elsewhere within and beyond our solar system?

Other ongoing projects, most with active NSF and NASA funding and student research opportunities, include (1) the molybdenum and iron isotope systematics of modern anoxic marine settings and the associated paleoenvironmental implications; (2) sulfate oxygen and sulfur isotope perspectives on Earth system evolution as refined through experimental microbiology and ground-truthing in the modern ocean; (3) collaborative geochemical exploration of recent drill cores from Western Australia that presage the Great Oxidation Event; (4) high-resolution, parallel carbon and sulfur isotope chemostratigraphy across organic carbon burial events in the Paleozoic; (5) the biogeochemistry of Cretaceous cold seeps in Colorado; (6) geochemical evidence for the causes and consequences of the Permo-Triassic extinction event as recorded globally; and (7) comparisons of Cretaceous oceanic anoxic events as preserved in deep and shallow marine sediments.

 Little, S. H., Vance, D., Lyons, T. W., McManus, J., 2015, Controls on trace metal authigenic enrichment in reducing sediments: insights from modern oxygen-deficient settings: American Journal of Science, v. 315, p. 77-119.

 Thomson, D., Rainbird, R.H., Planavsky, N., Lyons, T.W., Bekker, A., Chemostratigraphy of the Shaler Supergroup,Victoria Island, NW Canada: a record of ocean composition prior to the Cryogenian glaciations in Precambrian Research, 2015,

 Scott, C., Wing, B.A., Bekker, A., Planavsky, N.J., Medvedev, P., Bates, S.M., Yun, M., and Lyons, T.W., 2014, Pyrite multiple-sulfur isotope evidence for rapid expansion and contraction of the early Paleoproterozoic seawater sulfate reservoir: Earth and Planetary Science Letters, v. 389, p. 95-104.

Riedinger, N., Formolo, M.J., Lyons, T.W., Henkel, S., Voßmeyer, A., and Kasten, S., 2014, An inorganic geochemical argument for couple anaerobic oxidation of methane and iron reduction in marine sediments: Geobiology, v. 12, p. 172-181.

Reinhard, C.T., Planavsky, N.J., Wang, X., Fischer, W.W., Johnson, T.M., and Lyons, T.W., 2014, The isotopic composition of sedimentary chromium in a modern anoxic marine basin and controls on the chromium isotope composition of seawater. Earth and Planetary Science Letters, 407, p. 9-18.

Reinhard, C.T., Lalonde, S.V., and Lyons, T.W., 2014, Oxidative sulfide dissolution on the early Earth: Chemical Geology, v. 362, p. 44-55.

Planavsky, N.J., Reinhard, C.T., Wang, X., Thomson, D., McGoldrick, P., Rainbird, R.T., Johnson, T., Fischer, W., and Lyons, T.W., 2014, Low Mid-Proterozoic atmospheric oxygen levels and the delayed rise of animals: Science, v. 346, p. 635-638.

Planavsky, N.J., Asael, D., Hofmann, A., Reinhard, C.T., Lalonde, S.V., Wang, X., Knudsen, A., Ossa Ossa, F., Bekker, A., Johnson, T.M., Lyons, T.W., and Rouxel, O.J., 2014, Evidence for oxygenic photosynthesis half a billion years before the Great Oxidation Event: Nature Geoscience, v. 7, p. 283-286.

Partin, C.A., Lalonde, S.V., Planavsky, N.J., Bekker, A., Rouxel, O.J., Lyons, T.W., and Konhauser, K.O., 2014, Uranium in iron formations and the rise of atmospheric oxygen: Chemical Geology, v. 362, p. 82-90.

Lyons, T.W., Planavsky, N.J., and Reinhard, C.T., 2014, The rise of oxygen in the early ocean and atmosphere: Nature, v. 506, p. 307-315.

Lyons, T.W., Reinhard, C.T., and Planavsky, N.J., 2014, A fixed-nitrogen fix in the early ocean: Current Biology, v. 24, p. R276-R278.

Large, R.R., Halpin, J.A., Danyushevsky, L.V., Maslennikov, V.V., Bull, S.W., Long, J.A., Lottermoser, B.G., Gregory, D., Lounejeva, E., Lyons, T.W., McGoldrick, P., Haines, P.W., Sack, P.J., and Calver, C.R., 2014, A 3.5-billion-year record of trace element trends in the ocean: Earth and Planetary Science Letters, v. 389, p. 209-220.

Hardisty, D.S., Lu, Z., Planavsky, N.J., Bekker, A., Philippot, P., Zhou, Z., and Lyons, T.W., 2014, An iodine record of Paleoproterozoic surface ocean oxygenation. Geology, v. 42, p. 619-622.

Busigny, V., Planavsky, N., Jézéquel, D., Crowe, S., Louvat, P., Moureau, J., Viollier, E., and Lyons, T.W., 2014, Iron isotopes in an Archean ocean analogue: Geochimica et Cosmochimica Acta, v. 133, p. 443-462.

Asael, D., Tissot, F., Reinhard, C.T., Rouxel, O., Dauphas, N., Lyons, T.W., Ponzevera, E., Liorzou, C., and Chéron, S., 2014, Coupled molybdenum, iron and uranium stable isotopes as oceanic paleoredox proxies during the Paleoproterozoic Shunga Event: Chemical Geology, v. 362, p. 193-210.

Scott, C.T., Planavsky, N.J., Dupont, C.L., Kendall, B., Gill, B.C., Robbins, L.J., Husband, K.F., Arnold, G.L., Wing, B.A., Poulton, S.W., Bekker, A., Anbar, A.D., Konhauser, K.O., and Lyons, T.W., 2013, Marine zinc bioavailability through time and eukaryotic metallome evolution: Nature Geoscience, v. 6, p. 125-128.

Reinhard, C.T., Planavsky, N.J., Robbins, J., Partin, C., Gill, B.C., Lalonde, S.V., Bekker, A., Konhauser, K.O., and Lyons, T.W., 2013, Proterozoic ocean redox and evolutionary stasis: Proceedings of the National Academy of Sciences, v. 110, p. 5357-5362.

Reinhard, C.T., Planavsky, N.J., and Lyons, T.W., 2013, Long-term sedimentary recycling of rare sulphur isotope anomalies: Nature, v. 497, p. 100-103.

Partin, C.A., Bekker, A., Planavsky, N.J., Scott, C.T., Gill, B.C., Li, C., Podkovyrov, V., Maslov, A., Konhauser, K.O., Lalonde, S.V., Love, G.D., Poulton, S.W., and Lyons, T.W., 2013, Large-scale fluctuations in Precambrian atmospheric and oceanic oxygen levels from the record of U in shales: Earth and Planetary Science Letters, v. 369-370, p. 284-293.

Owens, J.D., Gill, B.C., Jenkyns, H.C., Bates, S.M., Severmann, S., Kuypers, M.M.M., Woodfine, R., and Lyons, T.W., 2013, Sulfur isotopes track the global extent and dynamics of euxinia during Cretaceous Oceanic Anoxic Event 2: Proceedings of the National Academy of Sciences, v. 110, p. 18407-18412.

Scott, C.T., and Lyons, T.W., 2012, Contrasting molybdenum cycling and isotopic properties in euxinic versus non-euxinic sediments and sedimentary rocks: Refining the paleoproxies: Chemical Geology, v. 324-325, p. 19-27.

Sahoo, S.K., Planavsky, N.J., Kendall, B., Wang, X., Shi, X., Scott, C., Anbar, A.D., Lyons, T.W., and Jiang, G., 2012, Ocean oxygenation in the wake of the Marinoan glaciation: Nature, v. 489, p. 546-549.

Planavsky, N., Rouxel, O.J., Bekker, A., Hofmann, A., Little, C.T.S., and Lyons, T.W., 2012, Iron isotope composition of some Archean and Proterozoic iron formations: Geochimica et Cosmochimica Acta, v.80, p.158-169.

Planavsky, N.J., Bekker, A., Hofmann, A., Owens, J.D., and Lyons, T.W., 2012, Sulfur record of rising and falling marine oxygen and sulfate levels during the Lomagundi event: Proceedings of the National Academy of Sciences, v. 109, p. 18300-18305.

Lyons, T.W., Reinhard, C.T., Love, G., and Xiao, S., 2012, Geobiology of the Proterozoic Eon, in Knoll, A.H., Canfield, D.E., and Konhauser, K.O. (eds.) Fundamentals of Geobiology, Blackwell, p. 371-402.

Scott, C., Bekker, A., Reinhard, C.T., Schnetger, B., Krapež, B., Rumble, D., and Lyons, T.W., 2011, Late Archean euxinic conditions before the rise of atmospheric oxygen: Geology, v. 39, p. 119-122.

Saltzman, M.R., Young, S.A., Kump, L.R., Gill, B.C., Lyons, T.W., and Runnegar, B., 2011, A pulse of atmospheric oxygen during the late Cambrian: Proceedings of the National Academy of Sciences, v. 108, p. 3876-3881.

Planavsky, N.J., McGoldrick, P., Scott, C.T., Li, C., Reinhard, C.T., Kelly, A.E., Chu, X., Bekker, A., Love, G.D., and Lyons, T.W., 2011, Widespread iron-rich conditions in Mid-Proterozoic oceans: Nature, v. 477, p. 448-451.

Lyons, T.W., and Reinhard, C.T., 2011, Sea change for the rise of oxygen: Nature, v. 478, p. 194-195.

Konhauser, K., Lalonde, S.V., Planavsky, N.J., Pecoits, E., Lyons, T.W., Mojzsis, S.J., Rouxel, O.J., Barley, M.E., Rosiere, C., Fralick, P.W., Kump, L.R., and Bekker, A., 2011, Aerobic bacterial pyrite oxidation and acid rock drainage during the Great Oxidation Event: Nature, v. 478, p. 369-373.

Gill, B.C., Lyons, T.W., Young, S.A., Kump, L.R., Knoll, A.H., and Saltzman, M.R., 2011, Geochemical evidence for widespread euxinia in the later Cambrian ocean: Nature, v. 469, p. 80-83.

Planavsky, N.J., Rouxel, O.J., Bekker, A., Lalonde, S.V., Konhauser, K.O., Reinhard, C.T., and Lyons, T.W., 2010, The evolution of the marine phosphate reservoir: Nature, v. 467, p. 1088-1090.

Lyons, T.W., and Gill, B.C., 2010, Ancient sulfur cycling and oxygenation of the early biosphere: Elements, v. 6, p. 93-99.

Li, C., Love, G.D., Lyons, T.W., Fike, D.A., Sessions, A.L., and Chu, X., 2010, A stratified redox model for the Ediacaran ocean: Science, v. 328, p. 80-83.

Kendall, B., Reinhard, C.T., Lyons, T.W., Kaufman, A.J., Poulton, S.W., and Anbar, A.D., 2010, Pervasive oxygenation along the late Archaean ocean margins: Nature Geoscience, v. 3, p. 647-652.

Duan, Y., Anbar, A.D., Arnold, G.L., Lyons, T.W., Gordon, G.W., and Kendall, B., 2010, Molybdenum isotope evidence for mild environmental oxygenation before the Great Oxidation Event: Geochimica et Cosmochimica Acta, v. 74, p. 6655-6668.

Reinhard, C., Raiswell, R., Scott, C., Anbar, A.D., and Lyons, T.W., 2009, A late Archean sulfidic sea stimulated by early oxidative weathering of the continents: Science, v. 326, p. 713-716.

Lyons, T.W., Reinhard, C.T., and Scott, C., 2009, Redox redux: Geobiology, v. 7, p. 489-494.

Lyons, TW, Reinhard, C.T., 2009, An early productive ocean unfit for aerobics. Proceedings of the National Academy of Sciences, v. 106, p.18045-18046.

Lyons, T.W., and Reinhard, C.T., 2009, Oxygen for heavy-metal fans: Nature, 461, p. 179-181.

Lyons, T.W., and Gill, B.C., 2009, The worm turned, and the ocean followed: Proceedings of the National Academy of Sciences, v. 106, p. 8081-8082.

Lyons, T.W., Anbar, A.D., Severmann, S., Scott, C., and Gill, B.C., 2009, Tracking euxinia in the ancient ocean: A multiproxy perspective and Proterozoic case study: Annual Reviews of Earth and Planetary Sciences, v. 37, p. 507-534.

Gordon, G.W., Lyons, T.W., Arnold, G.L., Roe, J., Sageman, B.B., and Anbar, A.D., 2009, When do black shales tell molybdenum isotope tales? Geology, v. 37, p. 535-538.

Scott, C., Lyons, T.W., Bekker, A., Shen, Y., Poulton, S.W., Chu, X., and Anbar, A.D., 2008, Tracing stepwise oxygenation of the Proterozoic ocean: Nature, v. 452, p. 456-459.

Lyons, T.W., 2008, Ironing out ocean chemistry at the dawn of animal life. Science, v. 321, p. 923-924.

Lyons, T.W., 2007, Oxygen’s rise reduced: Nature, v. 448, p. 1005-1006.

Kaufman, A.J., Johnston, D.T., Farquhar, J., Masterson, A.L., Lyons, T.W., Bates, S., Anbar, A., Arnold, G.L., Garvin, J., and Buick, R., 2007, Late Archean biospheric oxygenation and atmospheric evolution: Science, v. 317, p. 1900-1903.

Anbar, A.D., Duan, Y., Lyons, T.W., Arnold, G.L., Kendall, B., Creaser, R.A., Kaufman, A.J., Gordon, G.W., Scott, C., Garvin, J., and Buick, R., 2007, A whiff of oxygen before the great oxidation event? Science, v. 317, p. 1903-1906.

Lyons, T.W., and Severmann, S., 2006, A critical look at iron paleoredox proxies: New insights from modern euxinic marine basins: Geochimica et Cosmochimica Acta, v. 70, p. 5698-5722.

Algeo T.J., and Lyons, T.W., 2006, Mo–total organic carbon covariation in modern anoxic marine environments: Implications for analysis of paleoredox and paleohydrographic conditions: Paleoceanography, v. 21.

Johnston, D.T., Wing, B.A., Farquhar, J., Kaufman, A.J., Strauss, H., Lyons, T.W., Kah, L.C., and Canfield, D.E., 2005, Active microbial sulfur disproportionation in the Mesoproterozoic: Science, v. 310, p. 1477-1479.

Gellatly, A.M., and Lyons, T.W., 2005, Trace sulfate in Mid-Proterozoic carbonates and the sulfur isotope record of biospheric evolution: Geochimica et Cosmochimica Acta, v. 69, p. 3813-3829.

Kah, L.C., Lyons, T.W., and Frank, T.D., 2004, Low marine sulphate and protracted oxygenation of the Proterozoic biosphere: Nature, v. 431, p. 834-838.

Arnold, G.L., Anbar, A.D., Barling, J., and Lyons, T.W., 2004, Molybdenum isotope evidence for widespread anoxia in mid-Proterozoic oceans: Science, v. 304, p. 87-90.

Lyons, T.W., 2004, Warm debate on early climate: Nature, v. 429, p. 359-360.

More Information

General Campus Information

University of California, Riverside
900 University Ave.
Riverside, CA 92521
Tel: (951) 827-1012

UCR LibrariesCampus Status
Career OpportunitiesDiversity
Visit UCRMaps and Directions

Earth Sciences Information

Department of Earth Sciences
Geology Building

Tel: (951) 827-3182
Fax: (951) 827-4324