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Professor of Geosciences



Office: HAC 128


Robert Walter is a geologist, geochemist and geochronologist. He has conducted geological explorations and field research in East Africa (calibration of human origins, rift basin analyses, Plio-Pleistocene climate change, and volcanology), North America (Quaternary geology, surface water and groundwater interactions and environmental geology), around the Pacific Rim (neotectonics), and around the world (groundwater exploration). He was elected a Fellow of the California Academy of Science in 1989 and a Fellow of the Geological Society of America in 2011. He was the Chief Geologist for the Institute of Human Origins in Berkeley, California (1987-94) and a Senior Scientist at the University of Toronto Argon Dating Lab and the Jack Satterly Geochronology Laboratory at the Royal Ontario Museum, Toronto (1994-2000). He is a former American Association for the Advancement of Science (AAAS) Diplomacy Fellow and Senior Science Advisor to the U.S. Department of State (INR/HIU, 2003-04), where he conducted research on complex humanitarian emergencies, with a focus on Africa and the Near East. He was a Visiting Professor and Presidential Fellow at Case Western Reserve University (2005-06) and the Allen Cox Visiting Professor at Stanford University (2011-12). In 2011 he and Dorothy Merritts received the Kirk Bryan Award for Outstanding Research in Quaternary Geology and Geomorphology from the Geological Society of America for their 2008 paper in Science, "Natural Streams and the Legacy of Water Powered Mills." He is a Professor of Geosciences at Franklin and Marshall College (2006-Present), where his research interests are on bedrock fracture analyses, groundwater exploration, water quality analyses, soil-sediment-bedrock-water interactions, and human disturbances of earth surface processes.

He directs the Big Spring Run Restoration Experiment, authored over 90 peer-reviewed publications, and co-wrote and co-directed five short documentary films on human evolution. He is co-founder and Chief Science Officer of Power 7 Inc., a pioneering groundwater exploration company that specializes in discovering fresh groundwater where traditional methods fail to look, and he is the co-founder of the Water Science Institute, a not-for-profit research organization that promotes sustainable, science-based benefits of projects that provide available, clean water through conservation, restoration and exploration.

Full CV  (available on request)

ResearchGate profile (click)

Latest News 

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Betchel, Walter and Longnecker '17 at Boiling Springs, PA


B.A., Geology, Franklin and Marshall College

Ph.D., Geochemistry, Case Western Reserve University

Post-Doctoral Fellow, Department of Physics (Division of Geophysics), University of Toronto

Selected Publications 

I. Isotope Geochemistry and Geochronology, Volcanology, Tectonics

Anders, M.H., Rodgers, D. W., Hemming, S.R., Saltzman, J., DiVinere, V., Hagstrum, J.T., Embree, G.F., and WalterR.C., 2014. A fixed sub-lithospheric source for the late Neogene track of the Yellowstone hotspot: Implications of the Heise and Picabo Volcanic Fields. J. Geophys. Res., DOI: 10.1002/2013JB010483 (PDF)

Aronson, R.C., Schmitt, T.J., Walter, R.C., Taieb. M., Tiercelin, J-J., Naeser, C.W., and Nairn, A.E.M., 1977, New geochronological and paleomagnetic data for the hominid-bearing Hadar Formation of Ethiopia. Nature, 267, 323-337. (PDF)

Asfaw, B., Beyene, Y., Suwa, G., Walter, R.C., White., T.D., WoldeGabriel, G., Yemane, T., 1992, The Earliest Acheulian from Konso-Gardula, Nature360, 732-734. (PDF)

Bruggemann, J.H., Buffler, R.T., Guillaume, M.M., Walter, R.C., von Cosel, R., Ghenretensae, N., Berhe, S., 2004. Stratigraphy, paleoenvironments and model for the deposition of the Abdur Reef Limestone: Context for an important archaeological site from the last interglacial on the Red Sea coast of Eritrea. Palaeogeography, Palaeolclimatology, Palaeoecology 203, 179-206. (PDF)

Buffler, R.T., Walter, R.C., Ghebretensae, B.N., Bruggemann, J.H., Guillaume, M.M.M., Berhe, S.M., McIntosh, W., Park, L.E., 2010.  Geologic setting of the Abdur Archaeological Site on the Red Sea coast of Eritrea, Africa.  Global and Planetary Change 72, 429-450(PDF)

Chernet, T., Hart, W.K., Aronson, J.L., and Walter, R.C., 1998, New age constraints on the timing of volcanism and tectonism in the northern main Ethiopian Rift-southern Afar transition zone, Journal of Volcanology and Geothermal Research80, 267-280 (PDF)

Clark, J.D., Asfaw, B, Assefa, G., Harris, J.W.K., Kurishina, H., Walter, R.C., White, T.D., and Williams, M.A.J., 1984, Paleoanthropological discoveries in the Middle Awash valley. Nature307, 423-428. (PDF)

Clark, J.D., de Heinzelin, J., Schick, K.D., Hart, W.K., White, T.D., WoldeGabriel, G., Walter, R.C., Suwa, G., Asfaw, B., Vrba, E., Selassie, Y.H., 1994, African Homo erectus: Old Radiometric Ages and Young Oldowan Assemblages in the Middle Awash, Ethiopia, Science264, 1907-1910. (PDF)

Ebinger, C.J., Yemane, T., WoldeGabriel, T., Aronson, J.L., and Walter, R.C., 1993, Late Eocene-Recent volcanism and faulting in the southern main Ethiopian rift, Journal of the Geological Society, London150, 99-108. (PDF)

Johanson, D.C., Masao, F., Eck, G., White, T.D., Walter, R.C., Kimbel, W.H., Manega, P., 1987, New partial skeleton of Homo habilis from Olduvai Gorge, Tanzania. Nature327, 205-209. (PDF)

Johanson, D.C., Kimbel, W.H., Walter, R.C., Vondra, C., Yemane, T., Aronson, J.L., Eck, G.G., Rak, Y., Hovers, E., Reed, K.E., and Bobe-Quinteros, R., 1995, Fossil collecting; discussion, Science 268, 1113. (PDF)

Johnson, K.M., Snyder, N.P., Castle, S., Hopkins, A.J., Waltner, M., Merritts, D.J. and Walter, R.C., 2019. Legacy sediment storage in New England river valleys: Anthropogenic processes in a postglacial landscape. Geomorphology, 327, pp.417-437. https://doi.org/10.1016/j.geomorph.2018.11.017

Kimbel, W.H., Walter, R.C. and Johanson, D.C., et al., 1996, Late Pliocene Homo and Oldowan tools from the Hadar Formation (Kada Hadar Member). Ethiopia, Journal of Human Evolution31, 549-561. (PDF)

Longenecker*, J., T. Bechtel, Z. Chen, N. Goldscheider, T. Liesch, and R. Walter, 2017, Correlating Global Precipitation Measurement satellite data with karst spring hydrographs for rapid catchment delineation, Geophysical Research Letters44, 4926–4932, doi:10.1002/2017GL07379 0. http://onlinelibrary.wiley.com/doi/10.1002/2017GL073790/abstract

Pazzaglia, F.J., Braun, D.D., Pavich, M., Bierman, P., Potter, N., Jr., Merritts, D., Walter, R., and Germanoski, D., 2006, Rivers, glaciers, landscape evolution, and active tectonics of the central Appalachians, Pennsylvania and Maryland, in Pazzaglia, F.J., ed., Excursions in Geology and History: Field Trips in the Middle Atlantic States: Geological Society of America Field Guide 8, p. 169–197, doi: 10.1130/2006.fl d008(09). (PDF)

Shoshani, H., Walter, R.C., Berhe, S., Libsekal, Y. and Abraha, M., 2006., Paleoenvironments of Late Oligocene Gompothere from Dogali, Eritrea. Proceedings of the National Academy of Science. (PDF)

Renne, P.R., Deino, A.L., Walter, R.C., Turrin, B.D., Swisher, C.C., Becker, T.A., Curtis, G.H., Sharp, W.D. and Jaouni, A.-R., 1994, Intercalibration of astronomical and radioisotopic time, Geology 22, 783-786. (PDF)

Walter, R.C., 1989, Applications and limitations of fission-track geochronology to Quaternary tephras, Quaternary International1, 35-46. (PDF)

Walter, R.C., 1989, Applications of K/Ar and 40Ar/sAr dating to Quaternary geology. In: S.L. Forman, ed., “Dating Methods Applicable to Quaternary Geological Studies in the Western United States”.  Utah Department of Natural Resources Misc. Pub 98-7, 61-66. (PDF)

Walter, R.C., 1989, Tephrostratigraphy and tephrochronology. In: S.L. Forman, ed., “Dating Methods Applicable to Quaternary Geological Studies in the Western United States”.  Utah Department of Natural Resources Misc. Pub 98-7, 54-60. (PDF)

Walter, R.C., 1998. Potassium-Argon/Argon-Argon Dating. In: Chronometric and Allied Dating in Archaeology (R.E. Taylor and M. Aitken, eds.), Advances in Archaeology and Museum Science, Plenum Press, 97-127. (PDF)

Walter, R.C. and Aronson, J.L., 1982, Revisions of K/Ar ages for the Hadar hominid site, Ethiopia. Nature296, 122-127.

Walter, R.C., 1994, The Age of Lucy and the First Family: Single-Crystal 40Ar/39Ar Dating of the Denen Dora and lower Kada Hadar Members of the Hadar Formation, Ethiopia, Geology,  22, 6-10. (PDF)

Walter, R.C., et. al., 2000, Early human occupation of the Red Sea coast of Eritrea during the last interglacial, Nature 405, 65-69. (PDF)

Walter, R.C., Hart, W.K., and Westgate, J.L., 1987, Petrogenesis of a basalt-rhyolite tephra from the west-central Afar, Ethiopia. Contributions to Mineralogy and Petrology95, 462-480. (PDF)

Walter, R.C., Manega, P.C., Hay, R.L., 1992, Tephrochronology of Bed I, Olduvai Gorge: An Application of Laser-fusion 40Ar/39Ar Dating to Calibrating Biological and Climatic Change, Quaternary International13/14, 37-46. (PDF)

Walter, R.C., Manega, P.C., Hay, R.L., Drake, R.E., and Curtis, G.H., 1991, Laser-fusion 40Ar/39Ar Dating of Bed I, Olduvai Gorge, Tanzania, Nature354, 145-149. (PDF)

Walter, Robert, Merritts, Dorothy, Rahnis, Michael, Langland, Michael, Galeone, Daniel, Gellis, Allen, Hilgartner, William, Bowne, David, Wallace, John, Mayer, Paul, and Forshay, Ken, 2014, Big Spring Run floodplain-wetland aquatic resources restoration project:  Report to Pennsylvania Department of Environmental Protection, 78 p (plus figures, data files, GIS shapefiles, and photo archives).  link 

Walter. R.C., and Aronson, J.L., 1993, Age and Source of the Sidi Hakoma Tuff, Hadar Formation, Ethiopia, Journal of Human Evolution25, 229-240. (PDF)

Westgate, J.A., Preece, S.J., Froese, D.G., Walter, R.C., Sandu, A.S., and Scherger, C.E., 2001, Dating Early and Middle (Reid) Pleistocene Glaciations in Central Yukon by Tephrochronology, Quaternary Research 56, 335-348. (PDF)

Westgate, J.A., Walter, R.C., Pearce, W., and Gorton, M.P., 1985, Geochemistry, age and distribution of the Old Crow tephra, Yukon and Alaska. Canadian Journal of Earth Science, 22, 893-906. (PDF)

WoldeGabriel, G, White, T.D., Suwa, G., Semaw, S., Beyene, Y., Asfaw, B., and Walter, R.C., 1992, Kesem-Kebena: A Newly Discovered Paleoanthropology Research Area in Ethiopia, Journal of Field Archaeology19, 471-493. (PDF)

WoldeGabriel, G., Aronson, J.L., and Walter, R.C., 1990 Geology, geochronology, and rift development of the central sector of the Main Ethiopian Rift. Geological Society of America Bulletin 102, 439-458. (PDF)

WoldeGabriel, G., Walter, R.C., Aronson, J.L., and Hart, W.K., 1992, Geochronology and Distribution of Silicic Volcanic Rocks of Plio-Pleistocene Age from the Central Sector of the main Ethiopian Rift, Quaternary International13/14, 69-76. (PDF)

II. Critical Zone Studies, Landscape and Aqueous Geochemistry, Sediment Fingerprinting, Anthropocene Landscape Change, Stream Restoration

Brantley, S., Menonigal, P., Scatena, F., Balogh-Brunstad, Z., Barnes, R., Bruns, M., Van Cappelen, P., Dontsova., K., Hartnett, H., Hartshorn, T., Heismath, A., Herndon, E., Jin, L., Keller, C., Leake, J., McDowell, W., Meinzer, F., Mozdzer, T., Petsch, S., Pett-Ridge, J., Pregitzer, K., Raymond, P., Riebe, C., Shumaker, K., Sutton-Grier, A., Walter, R., Yoo, K., 2011, Twelve testable hypothesis on the geobiology of weathering. Geobiology. DOI: 10.1111/j.1472-4669.2010.00264.x (PDF)

Elliott, S.J., Wilf, P., Walter, R.C., Merritts, D.J., 2013, Subfossil Leaves Reveal a New Upland Hardwood Component of the Pre-European Piedmont Landscape, Lancaster County, Pennsylvania. PLoS ONE 8(11): e79317. doi: 10.1371/journal.pone.0079317 (PDF)

Elliott, Sara J., Grettenberger, Christen L., Donovan, Michael P., Wilf, Peter, Walter, Robert C., and Merritts, Dorothy J. 2016. Riparian and valley-margin hardwood species of pre-colonial Piedmont forests: A preliminary study of subfossil leaves from White Clay Creek, southeastern Pennsylvania, USA. Palaeontologia Electronica 19.1.2A: 1-26 (PDF)

Fleming, P.M., Merritts, D.J., and Walter, R.C., in press, Legacy sediment erosion hot spots: A cost-effective approach for targeting water quality improvements. Journal of Soil and Water Conservation. doi:10.2489/jswc.74.4.67AHall, C.M., Walter, R.C., Westgate, J.A., and York, D., 1984, The Cindery Tuff in Pliocene hominid-bearing sediments of the Middle Awash, Ethiopia: Geochronology, stratigraphy and geochemistry. Nature308, 26-31. (PDF)

Hartranft, J , Merritts, D., Walter, R., and and Rahnis, M., 2011, The Big Spring Run Restoration Experiment: Geomorphology, Aquatic Ecosystems, and Policy in the Big Spring Run Watershed, Lancaster County, PA. Sustain 24, 24-31. (PDF)

Inamdar, S., Johnson, E., Rowland, R., Warner, D., Walter, R. and Merritts, D., 2017, Freeze–thaw processes and intense rainfall: the one-two punch for high sediment and nutrient loads from mid- Atlantic watersheds. Biogeochemistry.https://doi.org/10.1007/s10533-017-0417-7

Merritts, D., Walter, R., and Rhanis, M., 2010, Sediment and nutrient loads from stream corridor erosion along breached millponds. Pennsylvania Department of Environmental Protection Report, 147p. (PDF)

Merritts, D., Walter, R., Rahnis, M., Hartranft, J., Cox, S., Potter, N., Hilgartner, W., Langland, M., Manion, L.*, Lippincott, C.*, Siddiqui, S.*, Rehman, Z.*, Scheid, C.*, Kratz, L.*, Shilling, A.*, Jenschke, M.*, Datin, K.*, Cranmer, E.*, Reed, A.*, Matuszewski, D.*, Voli, M.*, Ohlson, E.*, Deng, W.*, Neugebauer, A.*, Ahamed., A.*, Neal, C.*, Winter, A.*, and Becker, S.*, 2011. Anthropocene Streams: Human Agents in Base-Level Forcing, Philosophical Transactions of the Royal Society of London 369, 976-1009. (PDF)

Merritts, D.J., Walter, R.C., Rahnis, M., Hartranft, J, Cox, S.,  Scheid, C., Potter, N., Jenschke, M., Reed, A., Matuszewski, D., Kratz, L., Manion, L., Shilling, A., Datin, K., 2013, The rise and fall of Mid-Atlantic streams: Millpond sedimentation, milldam breaching, channel incision, and stream bank erosion. in DeGraff, J.V., and Evans, J.E., eds., The Challenges of Dam Removal and River Restoration: Geological Society of America Reviews in Engineering Geology, v. XXI, p. 183–203, doi:10.1130/2013.4021(14). (PDF)

Walter R.C. and Merritts, D.J., 2008. Natural Streams and the Legacy of Water-Powered Mills. Science 319, 299-304. (PDF)

Walter, R., Merritts, D. Patapova, M., Hilgartner, W., Bowne, D., Johnson, R., Moore, J., 2017, Wetland Program Development in Support of Pennsylvania’s Aquatic Resource Protection and Management Action Plan, Program Focus Area 3: Headwater Aquatic Resource Restoration Monitoring: Report to the Pennsylvania Department of Environmental Protection, 67 p (plus figures, data files and photo/video archives). (PDF)

Walter, Robert, Merritts, Dorothy, Rahnis, Michael, Langland, Michael, Galeone, Daniel, Gellis, Allen, Hilgartner, William, Bowne, David, Wallace, John, Mayer, Paul, and Forshay, Ken, 2014, Big Spring Run floodplain-wetland aquatic resources restoration project:  Report to Pennsylvania Department of Environmental Protection, 78 p (plus figures, data files, GIS shapefiles, and photo archives).  link

Walter, R.C. and Merritts, D.J., 2008. Dammed You Say. Science Online. (PDF 1 PDF2)

Walter, R.C. and Merritts, D.J., 2008. What to do About these Dammed Streams. Science, 321, 911-912. (PDF 1 PDF 2)

Walter, Merritts and Rahnis, 2007: Estimating Volume, Nutrient Content and Rates of Stream Bank Erosion of Legacy Sediment in the Piedmont and Valley and Ridge Physiographic Provinces, Southeastern and Central PA. PADEP Final Report. 103p. (PDF)

Weitzman, J., Forshay, K., Kaye, J., Mayer, P., Koval, J., Walter, R., 2014, Potential nitrogen and carbon processing  in a landscape rich in mill-dam legacy sediment. Biogeochemistry. DOI 10.1007/s10533-014-0003-1 (PDF)

III. Hydrogeology, Water Security, Groundwater Exploration

Faure, H., Walter, R.C. and Grant, D.E., 2002, The coastal oasis: Ice Age springs on emerged continental shelves, Global and Planetary Change, 33/1-2, 47-56. (PDF)

Longenecker, J., T. Bechtel, Z. Chen, N. Goldscheider, T. Liesch, and R. Walter, 2017, Correlating Global Precipitation Measurement satellite data with karst spring hydrographs for rapid catchment delineation, Geophys. Research Letters, 44, 4926–4932, doi:10.1002/2017GL073790.  link


Course Information


Main Course Sequence

GEO (ENE) 110 – The Dynamic Earth

GEO (ENE) 350 – Landscape Geochemistry

GEO (ENE) 480 – Geoscience Capstone Seminar – Global Tectonics


Elective Courses:

GEO (ENE) 170 – The Geopolitics of Afghanistan

GEO (ENE) 171 - The Geopolitics of Humanitarian Crises

GEO (ENE)/TDS 370 – Visual Design for Scientists (co-taught with Dirk Eitzen, TDS)

GEO (ENE) 375 – Karst Hydrogeology (co-taught with Tim Bechtel, ENE)

ENE/CLS 27x (in prep) – The Last Days of Pompeii (will co-teach with Shawn O’Bryhim, CLS)

Service to the College 

2006 to 2010 - International Off-Campus Study Committee

2011 to 2012 - Workplace Safety Committee

2011 to 2013 - Radiation Safety Committee

2013 to 2016 - Faculty Council (elected)

2016 to 2017 - Provost’s Campaign Advisory Council

2016 to 2017 – Distinguished Lecture Series Committee

2016 to Present - College Creativity and Innovation Advisory Group

2017 to 2018 - Faculty Fellow to the Faculty Center

2017 to 2020 - Professional Standards Committee (elected)