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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.


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