Research Interests

 

My research interests are in the areas of surficial geology and low-temperature mineralogy/geochemistry, especially as applied to bedrock aquifers, tropical soils and sedimentary rocks. Research methods include field work, X-ray diffraction, scanning electron microscopy, ICP-AES and other complementary methods of major and trace element analysis.

 

Research Papers (* = student co-author)

 

  • Ryan P.C., Kim J, Wall A.J., Moen, J.C.*, Corenthal, L.G.*, Chow, D.R.*, Sullivan, C.M.*, Bright, K.*, 2011. Ultramafic-derived arsenic in a fractured bedrock aquifer. Applied Geochemistry 26, 444-457. pdf

  • Ryan P.C., Huertas, F.J., 2009. The temporal evolution of pedogenic Fe-smectite to Fe-kaolin via interstratified kaolin-smectite in a moist tropical soil chronosequence. Geoderma 151, 1-15. pdf

  • Ryan P.C., Hillier S., Wall A.J.*, 2008, Stepwise effects of the BCR sequential chemical extraction procedure on dissolution and metal release from common ferromagnesian clay minerals: a combined solution chemistry and X-ray powder diffraction study. Science of the Total Environment 407, 603-614. pdf

  • Munroe J.S., Ryan P.C., Carlson H.A.*, and Miller E.K., 2008, Testing Latest Wisconsinan Ice Flow Directions in Vermont through Quantitative X-ray Diffraction Analysis of Soil Mineralogy. Northeastern Geology and Environmental Sciences, 29(4): 263-275. pdf

  • Munroe JS, Farrugia G*, Ryan PC. 2007. Parent material and chemical weathering in alpine soils on Mount Mansfield, Vermont, USA. Catena 70(1), 39-48. pdf

  • Fisher GB*, Ryan PC. 2006. The smectite to disordered kaolinite transition in a tropical soil chronosequence, Pacific Coast, Costa Rica. Clays & Clay Minerals 54, 571-586. pdf
    Click here for topographic map of Esterillos Terraces sample sites.

  • Kautz CQ*, Ryan PC. 2003. The 10 Å to 7 Å halloysite transition in a tropical soil sequence, Costa Rica. Clays and Clay Minerals 51, 252-263. pdf

  • Sears JW, Ryan PC. 2003. Cenozoic evolution of the Montana Cordillera: evidence from paleovalleys. Cenozoic Systems of the Rocky Mountain Region (Raynolds RG, Flores RM, Eds.), SEPM Special Publication, Denver, CO. pdf

  • Ryan PC, Wall AJ*, Hillier S, Clark L. 2002. Insights into sequential chemical extraction from quantitative XRD: A study of trace metal partitioning in sediments related to frog malformities. Chemical Geology 184, 337-357. pdf

  • Ryan PC, Hillier S. 2002. Facies relationships of Fe-rich clays in the Sundance Formation. American Mineralogist 87, 1607-1615. pdf

  • Hillier S, Ryan PC. 2002. Identification of halloysite (7Å) by ethylene glycol solvation: The MacEwan effect. Clay Minerals 37, 395-404. pdf

  • Ryan PC, Conrad ME, Brown K*, Chamberlain CP, Reynolds, RC Jr. 1998. Oxygen isotopic compositions of serpentine/chlorite and illite/smectite in the Tuscaloosa Formation (US Gulf Coast): Implications for pore fluids and mineralogic reactions. Clays and Clay Minerals 46, 357-368. pdf

  • Ryan PC, Buckley SN. 1998. Sedimentation, stratabound Cu-Ag mineralization, and syndepositional tectonics in the Revett Formation, Flathead Indian Reservation, western Montana: in The Belt Supergroup, Proc. Belt Symposium III, Special Pub. 112, Mont. Bur. of Mines Geol., 278-289. pdf

  • Ryan PC, Reynolds RC, Jr. 1997. The chemical composition of serpentine/chlorite: SEM-EDX vs. XRD determinations, implications for mineralogic reactions, and the origin of anatase. Clays and Clay Minerals 45, 339-352. pdf

  • Ryan PC, Reynolds RC, Jr. 1996. The origin and diagenesis of grain-coating serpentine/chlorite in Tuscaloosa Formation sandstone, U.S. Gulf Coast. American Mineralogist 81, 213-225. pdf

  • Moe JA, Ryan PC, Elliott WC, Reynolds RC, Jr. 1996. Petrology, chemistry, and clay mineralogy of a K-bentonite in the Proterozoic Belt Supergroup of western Montana: Journal of Sedimentary Research 66, 95-99. pdf

  • Buckley SN, Sears JW, Ryan PC, and Lauer D. 1994. Base-metal and PGE mineralization, sedimentation and mafic magmatism related to rifting of the Middle Proterozoic Belt Supergroup, western Montana: Northwest Geology 23 (Metallogeny of the Belt-Purcell Basin), 13-18. pdf

 

Recent Abstracts/Conference Presentations (* = student co-author)
  • Thompson, A.*, Ryan, P.C., Hattori, K.H., Kim, J., 2011, Geochemical and sulfur isotope analysis of Taconic slates: implications for arsenic source and mobility in a bedrock aquifer system. Geological Society of America Abstracts with Programs, Vol. 43, No. 1, p. 106.

  • Rosenberg, B.*, Bigl, M.F.*, Munroe, J.S., Ryan, P.C., 2011, X-ray diffraction analysis of weathering patterns in high-elevation glacial, periglacial, and eolian sediments in northern Nevada and Utah. Geological Society of America Abstracts with Programs, Vol. 43, No. 1, p. 114.

  • Rosenberg, B.*, Meyer, E.E., Ryan, P.C., Eberl, D.D., 2011, K-Ar dating of illite-rich rocks in the Champlain Valley, Vermont: an investigation of post-Taconian faulting and fluid flow. Geological Society of America Abstracts with Programs, Vol. 43, No. 1, p. 151.

  • Brooks, E.*, Kim, J., Ryan, P.C., 2011, Geochemical analysis of groundwater quality in the fractured bedrock aquifer of the town of Craftsbury, NE Vermont. Geological Society of America Abstracts with Programs, Vol. 43, No. 1, p. 107.

  • Mango, J., Ryan, P.C., 2011, Pyrite as the source of groundwater arsenic in Taconic slates, southwestern Vermont. Geological Society of America Abstracts with Programs, Vol. 43, No. 1, p. 135.

  • Ryan, P.C., Moen, J.C.*, Corenthal, L.G.*, Chow, D.R.*, Kim, J., 2010, Tetrahedral arsenic (As+5) in antigorite: Geological origin and implications for groundwater quality: SEA-CSSJ-CMS Trilateral Meeting on Clays, Spain, June 2010.

  • Clark, Arthur*, Smith, Taylor*, Kim, Jon, Ryan, Peter C., Mango, Helen, 2010, Elevated arsenic in domestic wells from the Taconic allochthons in southern Vermont. Geological Society of America Abstracts with Programs, Vol. 42, No. 1, p. 185.

  • Corenthal, Lilly*, Ryan, Peter C., Kim, Jon, 2010, Arsenic in groundwater wells in glacial drift, north-central Vermont. Geological Society of America Abstracts with Programs, Vol. 42, No. 1, p. 122.

  • Moen, Jonathan*, Ryan, Peter C., Kim, Jon, 2010, Analysis of arsenic speciation in ultramafic rocks by sequential chemical extraction: implications for Taconian fluid source and modern aquifer contamination. Geological Society of America Abstracts with Programs, Vol. 42, No. 1, p. 122.

  • Ryan, P.C., Kim, J., Clark, A.L.*, Smith, T.T.*, Chow, D.*, Sullivan, C., Bright, K., 2009, Ultramafic source of arsenic in a fractured bedrock aquifer. Geological Society of America Abstracts with Programs, Vol. 41, No. 7, p. 218.

  • Ryan, P.C. and Huertas, F.J., 2009, The origin of Fe-kaolin from precursor beidellite and interstratified kaolin-smectite in moist tropical soils. Programs and Abstracts, 14th International Clay Conference, Castellaneta, Italy, June 2009.

  • Ryan, P.C. and Huertas, F.J., 2009, Insights into the transformation of ferruginous beidellite to K-S and kaolin from synthesis experiments. Programs and Abstracts, 14th International Clay Conference, Castellaneta, Italy, June 2009.

  • Kim, J., Ryan, P., North, K.*, Bean, J.*, and Davis, L., 2009, Radionuclides, groundwater geochemistry, and hydrogeology above, below, and through the Hinesburg thrust: NW Vermont. Geological Society of America Abstracts with Programs, V. 41, n. 3, p. 21.

  • Ryan, P.C., Kim, J., Chow, D.*, Sullivan, C., and Bright, K., 2009, Connection between Ordovician mantle metasomatism and arsenic in Vermont groundwater. Geological Society of America Abstracts with Programs, V. 41, n. 3, p. 8.

  • Brachfeld, S., Manley, P., Gorring, M., and Ryan, P., 2007, Contributions of Sediment Provenance and Sediment Diagenesis to Western Antarctic Peninsula Magnetic Proxy Records. American Geophysical Union, Fall Meeting 2007, abstract #GP21B-04.

  • Gleason, Michael J.*, Kim, Jonathan, Coish, Raymond and Ryan, Peter C, (2007) Radionuclide-enriched groundwater, Knox Mountain pluton, Vermont: occurrence and lithologic controls, Geological Society of America Abstracts with Programs, v. 39, n. 1, p. 102.

  • Ryan, Peter C., Coish, Ray, and Joseph*, Kristiaan (2007), Ordovician K-Bentonites in western Vermont : mineralogic, stratigraphic and geochemical evidence for their occurrence and tectonic significance, Geological Society of America Abstracts with Programs, v. 39, n. 1, p. 50.

  • Sullivan, Colleen*, Bright, Kevin*, Kim, Jonathan, and Ryan, Peter C. (2007) Potential ultramafic-derived arsenic contamination in bedrock water wells in north-central Vermont, Geological Society of America Abstracts with Programs, v. 39, n. 1, p. 71.

  • North KP*, Kim J, Ryan P. 2005. Evaluation of geologic controls on elevated naturally-occurring radioactivity in bedrock ground water wells, NW Vermont. Geological Society of America 37 (1), 78.

  • Fisher GB*, Ryan PC. 2005. The ferruginous beidellite to halloysite transition in a tropical soil chronosequence. Clay Minerals Society 43rd Annual Meeting, 41. ** This paper won best student presentation at the meeting.

  • Cowden S*, Ryan PC, Greenglass N*. 2004. Lead in groundwater derived from a fractured carbonate aquifer (Clarendon Springs Formation), northwestern Vermont. Geological Society of America 36 (2), 66.

  • Ryan P, Hillier S, Wall A*, Wesolowski M*. 2004. Serpentinite weathering and trace metal mobility in dry tropical forest (NW Costa Rica) and cool temporate grassland (SW England). Geological Society of America 36 (5), 27.

  • Fisher GB*, Ryan PC. 2004. Clay mineral weathering sequence in a tropical terrace progression, Costa Rica. Geological Society of America 36 (2), 73.

  • Ryan PC, Hillier S, Wall AJ*. 2003. Trace metal speciation in soils derived from ultramafic rock, northwestern Costa Rica. Geological Society of America 34 (7), 241.

  • Cook R*, Ryan PC, Miller EK. 2003. Spatial variability in exchangeable calcium concentrations in Vermont spodosols. Geological Society of America 34 (7), 406.

  • Ryan PC, Hillier S. 2002. Berthierine-chamosite, corrensite and discrete chlorite from evolved verdine and evaporite-associated facies in the Jurassic Sundance Formation, Wyoming, USA. Prog. Abs., Clay Minerals Society, 39th Annual Mtg, Boulder, CO, p. 149.

  • Cook RC, Ryan PC, 2002. Differentiation of two Quaternary lahars by clay mineralogical, quantitative X-ray diffraction and particle size analyses. GSA Abstracts with Programs v. 34 (5), p. A28. ** This presentation won the best student poster award.

  • Kautz CQ*, Ryan PC. 2002. The mineralogical record of climate change in the John Day Formation, central Oregon. GSA Abstracts with Programs v. 34 (5), p. A26

  • Parris A, Bosley A, Noren A, Bierman P, Lini A, Ryan P. 2002. Holocene flood frequency in New England: Large, episodic events in the sediment record. GSA Abstracts with Programs v. 34.

  • Carlson HA*, Ryan PC. 2001. Quantitative XRD analysis of spodosols as a means of assessing response to acid deposition. GSA Abstracts with Programs v. 33, p. A362.

  • Kautz CQ*, Ryan PC. 2001. Formation of multiple halloysitic phases in a neotropical fluvial terrace Sequence. GSA Abstracts with Programs v. 33, p. A437.

  • Ryan PC, Hillier S. 2001. Paleoenvironmental significance of Fe-Mg clays in sandstones. GSA Abstracts with Programs v. 33, p. A73.

  • Ryan PC, Kautz CQ*. 2001. Formation of multiple halloysitic phases in a neotropical fluvial terrace sequence. Prog. Abs., Clay Minerals Society, 38th Annual Mtg, Madison, WI, p. 73.

  • Sullivan MY*, Ryan PC. 2001. Geochemical analysis of sediments in the Ompompanoosuc River near the Elizabeth Mine, South Strafford, Vermont. Geol Soc. America 33 (1).

  • Nichols D*, Ryan PC. 2001. Hydrothermal origin of Kaolinite at Brandon and Monkton, Vermont. Geol Soc. America 33 (1).

Middlebury College Theses Directed
2010-11

 

  • Geochemistry and Radionuclide Potential in a Fractured Bedrock Aquifer System, Craftsbury, Vermont. Erik Brooks ('11.5)
  • K--Ar Dating and Mineralogical Analysis of Illite-rich Rocks in the Champlain Valley: An Investigation of Post-Taconian Fluid Flow. Braden Rosenberg (’11)
  • Geochemical and Sulfur Isotope Analysis of Taconic Slates: Implications for Arsenic Source and Mobility in a Bedrock Aquifer System. Ali Thompson (’11.5)


2009-10

 

  • Arsenic in groundwater in glacial drift, north-central Vermont. Lilly Corenthal ('10)
  • Analysis of arsenic speciation in ultramafic rocks by sequential chemical extraction: Implications for Taconian fluid source and modern aquifer contamination. Jonathan Moen (’10)


2008-09

 

  • Geochemistry of U-rich groundwater and bedrock of the aquifer in the lower plate of the Hinesburg Thrust, Williston, Vermont. Jared Bean (’09)
  • Ground water and bedrock aquifer geochemistry of three monitoring wells, Stowe, Vermont. Daniel Chow (’09)
  • Mineralogy and geochemistry Quaternary paleosols, Granada, Spain. Tucker Levy (’09)


2006-07

 

  • An Historical Analysis of Sedimentation in Otter Creek, Pre-settlement to the Present
    Carrie Childs ('07). Co-advised with Pat Manley
  • Occurrence of and Lithologic Controls on Naturally Occurring Radioactivity in Groundwater, Northern Half of the Knox Mountain Pluton, Vermont.
    Michael Gleason ('07). Co-advised with Ray Coish
  • Evaluation of a Potential Ultramafic Source of Arsenic Contamination in Bedrock Water Wells in Central Vermont.
    Colleen Sullivan ('07)


2006

 

  • Geochemistry and mineralogy of spodosols along an elevational gradient, Bolton Mountain, Vermont.
    Dan Berkman ('06)
  • An evaluation of arsenic sources and extent in ground water in north-central Vermont..
    Kevin Bright ('06)
  • An assessment of the mineralogy and geochemistry of Ordovician K-bentonites in western Vermont.
    Kristiaan Joseph ('06)
  • Soil Geochemistry and mineralogy of the Bartlett Experimental Forest, White Mountains, New Hampshire..
    Lynne Zummo ('06)


2005

 

  • Selective chemical extraction of a series of natural soil specimens, and implications for reagent selectivity.
    Trevor Cloak (’05 - Environmental Chemistry).
  • Selective chemical extraction of a series of clay mineral standards, and implications for reagent selectivity.
    Nicole Grohoski (’05 - Environmental Chemistry).
  • The chemical composition of precipitation and stream outflow in a small watershed in the Breadloaf area, Ripton, Vermont..
    Caitlyn Long(’05 - Environmental Chemistry).
  • Evaluation of geological controls on elevated naturally-occurring radioactivity in bedrock ground water wells, NW Vermont.
    Katharine North (’05).


2004

 

  • Lead in ground water derived from a fractured carbonate aquifer (Clarendon Springs Formation), northwestern Vermont.
    Susannah Cowden ('04)
  • Rates of soil mineral formation in a tropical terrace progression, Pacific Coast, Costa Rica.
    G. Burch Fisher (’03.5).

 

2003

 

  • Evaluation of the Hazen’s Notch Formation as a source of trace metals to streams and soils, northern Vermont.
    Dana Chapin (’03).
  • Geochemical, stratigraphic and structural framework for natural sources of lead and uranium in groundwater in Addison County.
    Nora Greenglass (’03). Co-advised with David West.
  • Geochemical and mineralogical correlation of volcanic ash deposits, northern Chile.
    Brian McCurdy (’03).
  • Chemical weathering of serpentinites and trace metal mobility in soils and streams on the Lizard Peninsula, Cornwall, England.
    Marty Wesolowski (’03).

 

2002

 

  • Paleoclimatic record of clay minerals in the John Day Formation, Oregon.
    Christopher Kautz (’02).
  • Application of clay mineralogy and chemical analysis to stratigraphic correlation of Quaternary lahars, Mt. Hood.
    Robyn Cook (’02).
  • Trace metal mobility in association with ultramafic rock, East Dover, Vermont.
    Dana Drummond (’02).
  • Paleoclimatic record of clay minerals in the John Day Formation, Oregon.
    Christopher Kautz (’02).


2001

 

  • Mineralogy and origin of the Brandon Residual Formation/Brandon Lignite, Vermont.
    Drew Nichols (’01).
  • Sediment chemistry downstream of the Elizabeth copper mine, S. Strafford, VT.
    Maggie Sullivan (’01).
  • Modeling snow avalanche spatial and temporal distributions using snow-tel data, western US.
    David Selkowitz (’01- Geography).
  • Analysis of soil mineral formation in the wake of the 1980 eruption of Mt. St. Helens.
    Matt Whitcomb (’01).

 

2000

 

  • Heavy metal speciation and chemical weathering of ultramafic rock in Vermont.
    Brooke Laundon (’00). Co-advised with Ray Coish.
  • Mineralogy and geochemistry of the Raasay Ironstone, Inner Hebrides, Scotland.
    Elizabeth Hunter (’00).
  • Geochemical analysis of the logged and old growth forests, Middlebury Vermont.
    Josh Nothwang (’00).
  • Geochemical and macrofossil analysis of a lake sediment core as a record of Holocene environmental change in the Ritterbush Pond basin, northern Vermont.
    Amanda Ayres (’00). Co-advised with Andrea Lloyd.


1999

 

  • Analysis of heavy metals in 2 Vermont wetlands associated with frog malformations.
    Andrew Wall (99.5).
  • Geochemistry and mineralogy of iron-oxide acid drainage coatings, Pike Hill Mine, Vermont.
    Brian Totten (’99).
  • Geochemistry and mineralogy of sulfide-rich mine tailings, Pike Hill Mine, Vermont.
    Scott Wiercinski (’99).
  • Geochemistry of lateritic sediments in western Montana.
    Bryan Hopping (’99).