Brian Stewart


Associate Professor
Isotope Geochemistry
413 SRCC
4107 O'Hara Street
University of Pittsburgh
Pittsburgh, PA 15260
P: 412-624-8883
Curriculum Vitae


  • PhD in Geochemistry, 1990 University of California at Los Angeles

Courses Offered

Research Areas

  • Radiogenic isotope geochemistry
  • Nutrient cycling in soils
  • Geochronology and paleoenvironments of paleosols
  • Paleohydrology of arid regions
  • Environmental impact of coal and its byproducts

Representative Publications

Macpherson, G.L., Phan, T.T., Stewart, B.W. (2015) Direct determination (without chromatographic separation) of lithium isotopes in saline fluids using MC-ICPMS:  establishing limits on water chemistry. Journal of Analytical Atomic Spectroscopy 30, 1673-1678. Full PDF

Phan, T.T., Capo, R.C., Stewart, B.W., Graney, J.R., Johnson, J.D., Sharma, S., Toro, J. (2015) Trace metal distribution and mobility in drill cuttings and produced waters from Marcellus shale gas extraction: uranium, arsenic, barium. Applied Geochemistry 60, 89-103. Full PDF

Stewart, B.W., Chapman, E.C., Capo, R.C., Johnson, J., Graney, J., Kirby, C.S., Schroeder, K.T. (2015) Origin of brines, salts and carbonate from shales of the Marcellus Formation: Evidence from geochemical and Sr isotope study of sequentially extracted fluids. Applied Geochemistry 60, 78-88. Full PDF

Johnson, J.D., Graney, J.R., Capo, R.C., Stewart, B.W. (2015) Identification and quantification of regional brine and road salt sources in watersheds along the New York/Pennsylvania border, U.S.A. Applied Geochemistry 60, 37-50. Full PDF

Stewart, B.W., Capo, R.C., Kirby, C.S. (2015) Geochemistry of unconventional shale gas from formation to extraction: Petrogenesis, hydraulic fracturing, and environmental impacts (Preface). Applied Geochemistry 60, 1-2. Full PDF

Keating, E.H., Newell, D.L., Stewart, B.W., Capo, R.C., Pawar, R. (2014) Further insights into interconnections between the shallow and deep systems from a natural CO2 reservoir near Springerville, Arizona, U.S.A. Energy Procedia 63, 3195-3201. Full PDF

Newell, D.L., Perkins, G., Larson, T., Pugh, J.D., Stewart, B.W., Capo, R.C., and Trautz, R. (2014) Tracing CO2 leakage into groundwater using carbon and strontium isotopes during a controlled CO2 release field test. International Journal of Greenhouse Gas Control 29, 200-208. Full PDF

Kolesar Kohl, C.A., Capo, R.C., Stewart, B.W., Wall, A.J., Schroeder, K.T., Hammack, R.W., Guthrie, G.D. (2014) Strontium isotopes test long-term zonal isolation of injected and Marcellus Formation water after hydraulic fracturing. Environmental Science and Technology 48, 9867-9873. Full PDF

Macpherson, G.L., Capo, R.C., Stewart, B.W., Phan, T.T., Schroeder, K.T., Hammack, R.W. (2014) Temperature-dependent Li isotope ratios in Appalachian Plateau and Gulf Coast Sedimentary Basin saline water. Geofluids 14, 419-429. Full PDF

Capo, R.C., Stewart, B.W., Rowan, E.L., Kolesar, C.A., Wall, A.J., Chapman, E.C., Hammack, R.W., Schroeder, K.T. (2014) The strontium isotopic evolution of Marcellus Formation produced waters, southwestern Pennsylvania. International Journal of Coal Geology 126, 57-63. Full PDF

Hammack, R.W., Harbert, W., Sharma, S., Stewart, B.W., Capo, R.C., Wall, A.J., Wells, A., Diehl, R., Blauschild, D., Sams, J., Veloski, G. (2014) An Evaluation of Fracture Growth and Gas/Fluid Migration as Horizontal Marcellus Shale Gas Wells are Hydraulically Fractured in Greene County, Pennsylvania. NETL-TRS-3-2014; EPAct Technical Report Series; U.S. Department of Energy, National Energy Technology Laboratory: Pittsburgh, PA, 76 p. Full PDF

Soeder, D.J., Sharma, S., Pekney, N., Hopkinson, L., Dilmore, R., Kutchko, B.G., Stewart, B.W., Carter, C., Hakala, J.A., Capo, R.C. (2014) An approach for assessing engineering risk from shale gas wells in the United States. International Journal of Coal Geology 126, 4-19. Full PDF

Wall, A.J., Capo, R.C., Stewart, B.W., Phan, T.T., Jain, J.C., Hakala, J.A., Guthrie, G.D. (2013) High throughput method for Sr extraction from variable matrix waters and 87Sr/86Sr isotope analysis by MC-ICP-MS. Journal of Analytical Atomic Spectrometry 28, 1338-1344. Full PDF

Brubaker, T.M., Stewart, B.W., Capo, R.C., Schroeder, K.T., Chapman, E.C., Spivak-Birndorf, L.J., Vesper, D.J., Cardone, C.R., Rohar, P.C. (2013) Coal fly ash interaction with environmental fluids: Geochemical and strontium isotope results from combined column and batch leaching experiments. Applied Geochemistry 32, 184-194. Full PDF

Chapman, E.C., Capo, R.C., Stewart, B.W., Hedin, R.S., Weaver, T.J., Edenborn, H.M. (2013) Strontium isotope quantification of siderite, brine, and acid mine drainage contributions to abandoned gas well discharges in the Appalachian Plateau. Applied Geochemistry 31, 109-118. Full PDF

Amundson, R., Dietrich, W., Bellugi, D., Ewing, S., Nishiizumi, K., Chong, G., Owen, J., Finkel, R., Heimsath, A., Stewart, B., and Caffee, M. (2012) Geomorphologic evidence for the late Pliocene onset of hyperaridity in the Atacama Desert. Geological Society of America Bulletin 124, 1048-1070. Full PDF

Schatzel, S.J. and Stewart, B.W. (2012) A provenance study of mineral matter in coal from Appalachian Basin coal mining regions and implications regarding the respirable health of underground coal workers: A geochemical and Nd isotope investigation. International Journal of Coal Geology 94, 123-136. Full PDF

Chapman, E.C., Capo, R.C., Stewart, B.W., Kirby, C.S., Hammack, R.W., Schroeder, K.T., Edenborn, H.M. (2012) Geochemical and strontium isotope characterization of produced waters from Marcellus Shale natural gas extraction. Environmental Science and Technology 46, 3545-3553. Full PDF

Spivak-Birndorf, L.J., Stewart, B.W., Capo,  R.C., Chapman, E.C., Schroeder, K.T., Brubaker, T.M. (2012) Strontium isotope study of coal utilization byproducts interacting with environmental waters. Journal of Environmental Quality 41, 144-154. Full PDF

Keating, E., Viswanathan, H., Fessenden, J., Carey, J., Guthrie, G., Hakala, J., Capo, R., Stewart, B., and Gardiner, J. (2011) The challenge of predicting groundwater quality impacts in CO2 leakage scenarios: Results from field, laboratory, and modeling studies at a natural analog site in New Mexico, USA. Energy Procedia 4, 3239-3245. Full PDF

Hamel, B.L., Stewart, B.W. and Kim, A.G. (2010) Tracing the interaction of acid mine drainage with coal utilization byproducts in a grouted mine: Strontium isotope study of the inactive Omega Coal Mine, West Virginia (USA). Applied Geochemistry 25, 212-223. Full PDF

Liu, R., Wolfe, A.L., Dzombak, D.A., Horwitz, C.P., Stewart, B.W., and Capo, R.C. (2009) Controlled electrochemical dissolution of hydrothermal and sedimentary pyrite. Applied Geochemistry 24, 836-842. Full PDF

Cole, R.B. and Stewart, B.W. (2009) Continental margin volcanism at sites of spreading ridge subduction:  Examples from southern Alaska and western California. Tectonophysics 464, 118-136. Full PDF

Liu, R., Wolfe, A.L., Dzombak, D.A., Horwitz, C.P., Stewart, B.W., and Capo, R.C. (2008) Electrochemical study of hydrothermal and sedimentary pyrite dissolution. Applied Geochemistry 23, 2724-2734. Full PDF

Liu, R. Wolfe, A.L., Dzombak, D.A., Stewart, B.W., and Capo, R.C. (2008). Comparison of dissolution under oxic acid drainage conditions for eight sedimentary and hydrothermal pyrite samples.  Environmental Geology 56, 171-182. Full PDF

Ewing, S., Yang, W., DePaolo, D.J., Michalski, G., Kendall, C., Stewart, B.W., Thiemens, M. and Amundson, R. (2008) Non-biological fractionation of stable Ca isotopes in soils of the Atacama Desert, Chile. Geochimica et Cosmochimica Acta 72, 1096-1110. Full PDF

Wolfe, A.L., Liu, R., Stewart, B.W., Capo, R.C. and Dzombak, D.A. (2007) A method for generating uniform size-segregated pyrite particle fractions, Geochemical Transactions 8:9 doi:10.1186/1467-4866-8-9; 8p. Full PDF

Watanabe, Y., Stewart, B.W. and Ohmoto, H. (2004) Organic- and carbonate-rich soil formation ~2.6 billion years ago at Schagen, East Transvaal district, South Africa. Geochimica et Cosmochimica Acta 68, 2129-2151. Full PDF

Doran, P.T., Clifford, S.M.,  Forman, S.L., Nyquist, L., Papanastassiou, D.A., Stewart B.W., Sturchio, N.C., Swindle, T.D., Cerling, T., Kargel, J., McDonald, G., Nishiizumi, K., Poreda, R., Rice, J. & Tanaka, K. (2004) Mars chronology:  assessing techniques for  quantifying surface processes. Earth Science Reviews 67, 313-337. Full PDF

Schatzel, S.J. and Stewart, B.W. (2003) Rare earth element sources and modification in the Lower Kittanning coal bed, Pennsylvania:  implications for the origin of coal mineral matter and rare earth element exposure in underground mines. International Journal of Coal Geology 54, 223-251. Full PDF

Pretti, V.A. and Stewart, B.W. (2002) Solute sources and chemical weathering in the Owens Lake watershed, eastern California. Water Resources Research 38, 2-1–2-18,  doi:10.1029/2001WR000370. Full PDF

Stewart, B.W., Capo, R.C., and Chadwick, O.A. (2001) Effects of rainfall on weathering rate, base cation provenance, and Sr isotope composition of Hawaiian soils. Geochimica et Cosmochimica Acta 65, 1087-1099. Full PDF

Whipkey, C.E., Capo, R.C., Chadwick, O.A., and Stewart, B.W. (2000) The importance of sea spray to the cation budget of a coastal Hawaiian soil: a strontium isotope approach. Chemical Geology 168, 37-48. Full PDF

Stewart, B.W., Capo, R.C. and Chadwick, O.A. (1998) Quantitative strontium isotope models for weathering, pedogenesis and biogeochemical cycling.  Geoderma 82, 173-195. Full PDF

Capo, R.C., Stewart, B.W. and Chadwick, O.A. (1998) Strontium isotopes as a tracer of earth surface processes: Theory and methods.  Geoderma 82, 197-225. Full PDF

Stewart, B.W., Papanastassiou, D.A. and Wasserburg, G.J. (1996) Sm-Nd systematics of a silicate inclusion from the Caddo IAB iron meteorite.  Earth and Planetary Science Letters 143, 1-12. Full PDF

Stewart, B.W. and DePaolo, D.J. (1996) Isotopic studies of processes in mafic magma chambers: III.  The Muskox intrusion, Northwest Territories, Canada. In S.R. Hart and A.R. Basu, eds., Earth Processes:  Reading the Isotopic Code. Geophysical Monograph 95.  New York, American Geophysical Union, 277-292. Full PDF

Stewart, B.W., Papanastassiou, D.A. and Wasserburg, G.J. (1994) Sm-Nd chronology and petrogenesis of mesosiderites.  Geochimica et Cosmochimica Acta 58, 3487-3509. Full PDF

Stewart, B.W. and DePaolo, D.J. (1992) Diffusive isotopic contamination of mafic magma by coexisting silicic liquid in the Muskox intrusion.  Science 255, 708-711. Full PDF

Stewart, B.W. and DePaolo, D.J. (1990) Isotopic studies of processes in mafic magma chambers: II.  The Skaergaard intrusion, East Greenland.  Contributions to Mineralogy and Petrology 104, 125-141. Full PDF


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