Department of Geology

Rhawn F. Denniston

Tel: (319) 895-4306

Cornell College

 

Fax: (319) 895-5667

Mount Vernon, Iowa 52314

 

RDenniston@CornellCollege.edu

 

 

Education

Ph.D., Geosciences, University of Iowa, Iowa City, Iowa, 2000

M.S., Earth & Planetary Science, University of New Mexico, Albuquerque, New Mexico, 1995

B.A., Geology, Hamilton College, Clinton, New York, 1991

 

Professional Experience

Associate Professor of Geology, Cornell College, Mt. Vernon, Iowa 2006 - present

Visiting Research Scientist, University of New Mexico Department of Earth and Planetary Sciences, 2006-2007

Chair, Department of Geology, Cornell College, 2003 - present

Chair, Environmental Studies Program Committee, Cornell College, 2001 - present

Adjunct Professor, Department of Geosciences, University of Iowa, 2001 - present

Assistant Professor of Geology, Cornell College, Mt. Vernon, Iowa, 2000 - present

 

Fellowships & Awards

T. Anne Cleary Dissertation Research Fellowship, University of Iowa, 1999

Outstanding Teaching Assistant, University of Iowa, 1998

Howard Urbach Award, Richmond Area Speleological Society, 1998

Trowbridge Award for Outstanding Geology Doctoral Student, University of Iowa, 1997

Associated Western Universities Fellowship, Los Alamos National Laboratories, 1993-94

 

Publications

Published Manuscripts

Denniston, R.F., Asmerom, Y., Polyak, V., McNeill, D.F., Klaus, J.S., Cole, P., and Budd, A.F. (2008) Caribbean Chronostratigraphy Refined with U-Pb Dating of a Miocene Coral. Geology, 36, 151-154.

Denniston, R.F., Penn, S.C., Carpenter, S.J., and Budd, A.F. (in press) Constraints on Late Miocene Shallow Marine Seasonality for the Central Caribbean using d 18 O and Sr/Ca Ratios in a Fossil Coral. In Nehm, R.H. and A. F. Budd (Eds). Evolutionary Stasis: Species and Communities through Geological Time. Springer: New York.

Denniston, R.F., DuPree, M., Asmerom, Y., Polyak, V. Dorale, J.A., and Carpenter (2007) Episodes of Increased Aridity in the Late Holocene Recorded by Stalagmites from Devils Icebox Cave, Central Missouri, USA . Quaternary Research , 68 , 45-52.

Denniston, R.F., Asmerom, Y., Polyak, V. Dorale, J.A., Carpenter, S.J., Trodick, C. Hoye, B., and Gonz‡lez, L.A. (2007) Synchronous millenial-scale climatic changes in the Great Basin and the North Atlantic during the last interglacial. Geology , 35 , 619-622.

Baker, R.G., Bettis E.A. III, Denniston, R.F., Gonz‡lez, L.A., Strickland, L.E. and Krieg, J.R. (2002) Holocene paleoenvironments in southeastern Minnesota

chasing the prairie-forest ecotone.  Palaeogeography, Palaeoclimatology, Palaeoecology, 177, 103-122.

Denniston, R.F., Gonz‡lez, L.A., Polyak, V., Asmerom, Y., Reagan, M.K., and Saltzman, M.R. (2001) A high-resolution speleothem record of climatic variability

during the Aller¿d-Younger Dryas transition in Missouri, central United States. Palaeogeography, Palaeoclimatology, Palaeoecology, 176, 147-155.

Baker, R.G., Bettis, E.A., III, Denniston, R.F., and Gonz‡lez, L.A. (2001) Plant remains, alluvial chronology, and cave speleothem isotopes indicate abrupt

Holocene climatic change in Midwestern USA. Global and Planetary Change, 28, 285-291.

Denniston, R.F., Gonz‡lez, L.A., Asmerom, Y., Sharma, R.H., and Reagan, M.K, (2000) Speleothem evidence for changes in Indian summer monsoon

precipitation over the last ~2300 years. Quaternary Research , 53, 196-202.

Denniston, R.F., Gonz‡lez, L.A., Asmerom, Y., and Reagan, M.K. (2000) Speleothem records of Holocene paleoenvironmental change in the Ozark Highlands,

U.S.A. Quaternary International, 67, 21-28.

Denniston, R.F., Gonzalez, L.A., Semken, H.A., Jr., Baker, R.G., Recelli-Snyder, H., Reagan, M.K., and Bettis, E.A., III. (1999) Integrating stalagmite,

vertebrate, and pollen sequences to investigate Holocene vegetation and climate change in the southern Midwest. Quaternary Research, 52, 381-387.

Denniston, R.F., Gonzalez, L.A., Baker, R.G., Asmerom, Y., Reagan, M.K., Edwards, R.L., and Alexander, C.E. (1999) Speleothem evidence for a sharp and

long-term prairie-forest ecotone at the northeast border of the middle Holocene prairie peninsula.  The Holocene, 9, 671-676.

Denniston, R.F., Gonz‡lez, L.A., Asmerom, Y., Baker, R.G., Reagan, M.K. and Bettis, E.A. III. (1999) Evidence for increased cool season moisture during the

middle Holocene. Geology, 27, 815-818.

Denniston, R.F., Shearer, C.K., Vaniman, D.T., and Layne, G.D. (1997) Minor and trace element distributions in fracture calcites from Yucca Mountain, Nevada.

Geochimica et Cosmochimica Acta, 61, 1803-1818.

Hickmott, D.D., Herrin, J.M., Abel, R., George, M., Stimac, J., Gauerke, E.R., and Denniston, R.F.  (1997) Environmental applications of the LANL nuclear

microprobe. Nuclear Instruments and Methods in Physics Research B, 130, 564-570.

 

Abstracts

Krogmeier, D., Denniston, R.F., Carpenter, S.J., Dorale, J.A., Polyak, V., and Asmerom, Y. (2006) A stalagmite record of the penultimate deglaciation from

northwestern Arkansas. Iowa Academy of Science Annual Meeting Program with Abstracts, Buena Vista University, Storm Lake, IA.

Lommler, M., Denniston, R.F., and Budd, A.F. (2006) Comparison of U/Ca and Sr/ca ratios in Neogene corals from the Dominican Republic. Geological

Society of America Spring Meeting Program with Abstracts, v. 38, no. 4, pg. 37-11.

Trodick, C.T., Denniston, R.F., Asmerom, Y., Polyak, V., Haws, J. and Souto, P. (2006) U-Th chronologies of stalagmites from Almonda Cave, western

Portugal. Geological Society of America Spring Meeting Program with Abstracts, v. 38, no. 4, pg. 20-1.

Moellers, L., Denniston, R.F., Carpenter, S.J., Dorale, J.A., Polyak, V., and Asmerom, Y. (2006) A stalagmite record of the penultimate deglaciation from

northwestern Arkansas. Geological Society of America Spring Meeting Program with Abstracts, v. 38, no. 4, pg. 20-2.

Borowske, A.C., Denniston, R.F., Haws, J.F., Carpenter, S.J., and Dorale, J.A. (2005) A stable isotopic analysis of an end Pleistocene-age stalagmite from

Almonda cave, west-central Portugal. Geological Society of America Spring Meeting Program with Abstracts.

Cole, P., Denniston, R.F., Polyak, V.P., McNeill, D.F., and Budd, A. (2005) Uranium-lead dating of a coral from the Neogene Gurabo formation, Dominican

republic. Geological Society of America Spring Meeting Program with Abstracts.

Hoye, B., Denniston, R.F., Carpenter, S.J., Dorale, J.A., Asmerom, Y., Polyak, V.Y. (2005) Stable isotopic trends in a 23-26 ka Arkansas stalagmite.

Geological Society of America Spring Meeting Program with Abstracts.

Baker, R.G., Dorale, J.A., Bettis, E.A., Moss, P., and Denniston, R.F. (2004) Contrasts in prairie-forest border dynamics in the northern vs. southern Midwest.

American Quaternary Association 18th Biennial Meeting Program with Abstracts, Lawrence, KS, 107-108.

Denniston, R.F. (2004) Preliminary geochemical analysis of corals from the Neogene Gurabo Formation, Dominican Republic. 116th Annual Meeting of Iowa

Academy of Science, Cedar Falls, Iowa, April 24.

Denniston, R.F. and Penn, S. (2004) Suitability of corals from the Gurabo Formation, Dominican Republic, for geochemically-based SST reconstructions. 

Geological Society of American North-Central Meeting Abstracts with Programs, 36, 52.

Denniston, R., DuPree, M.A., Asmerom, Y., and Polyak, V.P (2003) Paleoclimatic implications of U-series dating of aragonite and calcite stalagmites from central

Nepal. Geological Society of America Fall Meeting Abstracts with Programs, 35, 172.

DuPree, M.A., Denniston, R.F., Asmerom, Y., and Carpenter, S.J. (2003) A 4000-year speleothem stable isotopic record from Devils Ice Box cave, central

Missouri. Geological Society of America Spring Meeting Abstracts with Programs, Paper No. 19-1.

Hartman, B.S., Gonzalez, L.A., Wulff, A.H. and Denniston, R.F. (2000) Carbon and oxygen isotopic analysis of speleothems from the Pokhara Valley, central

Nepal: a record of seasonal to decadal variability in the Indian summer monsoon. American Geophysical Union Fall Meeting Abstracts with Programs, 81,

F32.

Denniston, R.F., Gonz‡lez, L.A., and Reagan, M.K. (2000) Mineralogic and stable isotopic characteristics of select Great Basin speleothems.  Geological Society

of America Spring Meeting Abstracts with Programs, 32, A-11.

Denniston, R.F. and Gonzalez, L.A. (2000) Holocene environmental change in the Ozarks as deduced from stalagmites. 16th Biennial American Quaternary

Association Meeting Abstracts with Programs, Fayetteville, AR, 5-7.

Gonz‡lez, L.A., Denniston, R.F., Reagan, M.K., Ciochon, R., and Asmerom, Y. (1999) The use of stalagmites in the study of the history of the Asian monsoon

system.  Geological Society of America Fall Meeting Abstracts with Programs, 31, 89.

Denniston, R.F., Gonz‡lez, L.A., Reagan, M.K., and Asmerom, Y. (1999) A high-resolution record of Indian summer monsoon variability preserved by

speleothem carbonate mineralogy.  Geological Society of America Fall Meeting Abstracts with Programs, 31, 153.

Denniston, R.F., Gonz‡lez, L.A., Reagan, M.K., and Asmerom, Y. (1999) Effects of the Younger Dryas on the carbon and oxygen isotopic compositions of a

Missouri speleothem.  Geological Society of America Spring Meeting Abstracts with Programs, 31, 13.

Denniston, R.F., Gonzalez, L.A., Semken, H.A., Reagan, M.K., and Asmerom, Y. (1998) Combining speleothem carbon and faunal assemblages to examine

vegetation change in the southern Midwest. Geological Society of America Fall Meeting Abstracts with Programs, 30, 167.

Gonzalez, L.A., Denniston, R.F., Baker, R.G., and Reagan, M.K. (1998) Speleothem-based timing for prairie incursion in southeastern Minnesota and

northeastern Iowa and its implication on temperature vs. changes in E-T balance during the mid-Holocene. Geological Society of America Fall Meeting

Abstracts with Programs, 30, 114.

Denniston, R.F., Gonzalez, L.A., Asmerom, Y., Baker, R.G., and Reagan, M.K. (1998) Correlating speleothem carbon and pollen records from the southern

Midwest: tracking Holocene vegetation changes. American Quaternary Association Meeting Program with Abstracts, Puerto Vallarta, 103.

Denniston, R.F., Gonz‡lez, L.A., Baker, R.G., Reagan, M.K. Bettis, E.A., III, Asmerom, Y. and Pickett, D. A. (1998) Effects of middle Holocene vegetation

change on the oxygen and carbon isotopic composition of three midwestern speleothems. American Geophysical Union Fall Meeting Abstracts with

Program, 79, 107.

Denniston, R.F. and Gonzalez, L.A. (1997) Microsampling and isotopic analysis of adjacent fluorescent/non-fluorescent band couplets in a Midwestern

speleothem. Geological Society of America Spring Meeting Abstracts with Programs, 29, 12.

Denniston, R.F. and Shearer, C.K. (1995) A mineralogical approach to understanding fluid flow in shallow crustal regimes: application to forecasting the integrity of

potential waste repositories.  WERC Meeting, Las Cruces, NM.

Denniston, R.F., Shearer, C.K., and Vaniman, D.T. (1994) Application of cathodoluminescence and minor-trace element micro-analysis for deciphering the

crystallization history of calcite from shallow crustal regimes. American Geophysical Union Spring Meeting Abstracts with Program, Baltimore, 75, 121.

Denniston, R.F., Shearer, C.K., and Vaniman, D.T. (1994) An ion microprobe study of trace element (REE, Mn, Sr) zoning in calcite from shallow crustal

regimes.  American Geophysical Union Fall Meeting Abstracts with Program, San Francisco, 75, 698.

Denniston, R.F., Shearer, C.K., Vaniman, D.T., and Hickmott, D.D. (1993) Analysis of elemental zoning in calcites from fracture systems at Yucca Mountain,

Nevada: preliminary investigations and results. Fifth Annual Associated Western Universities Annual Meeting, Carlsbad, NM, 72.

Denniston, R.F., Gauerke, E., Shearer, C.K., Vaniman, D.T., and Hickmott, D.D. (1993) Trace element distributions in fracture calcites from Yucca Mountain,

Nevada: implications for shallow crustal transport phenomena.  American Geophysical Union Fall Meeting Abstracts with Program, San Francisco,74, 677.

Tewksbury, B.J., Cunningham, A.C., and Denniston, R.F. (1991) A kinematic analysis of the Payne Lake leucogneiss, northwest Adirondack Lowlands, New

York.  Geological Society of America Spring Meeting Abstracts with Program, Baltimore, 23, 193.

 

Non-Peer Reviewed Publications

Denniston, R.F. and Denniston, J.R. (2003) Cave Formations Reveal Climate and Archeological Change in New Mexico Magazine, New Mexico State Tourism

Publication.

Denniston, R.F. (1999 and subsequent editions) Geology of the Southwest, Geology of the Grand Canyon, Geology of Carlsbad National Park, in Lonely Planet

Guide to the Southwest: Arizona, New Mexico, Utah (R. Rachioweicki, Ed.), Lonely Planet Publishers, Melbourne, 28-31, 430-431, 954.

Denniston, R.F. (1999 and subsequent editions) Geology of North America, in Lonely Planet Guide to the U.S.A. (R. Rachioweicki, Ed.), Lonely Planet

Publishers, Melbourne, 30-33.

Denniston, R.F. (1999) Geology of the Rio Grande Rift, in The History of Corrales, New Mexico (C. Tidwell, Ed.), 16-21.

 

Invited Publications and Presentations

"Formation of the Central American Isthmus and 5 Million Years of Faunal Turnover in the Caribbean" Edgewood College (Madison, WI) Environmental Studies

Seminar, April 16, 2004.

"Towards Caribbean Seasonal Sea Surface Temperature and Salinity Variability from Neogene Corals" University of Dubuque (Dubuque, IA) Department of

Environmental Science Guest Lecture, November 14, 2003.

"Stalagmites as Paleoclimatic Records" Augustana College (Rock Island, IL) Geology Department Seminar, April 25, 2003.

"Understanding Climatic Change using Speleothems" University of Northern Iowa Department of Geography, Geomorphology Course Guest Lecture, April 21,

2003.

"Paleoclimatic Implications of a Negative Oxygen Isotopic Excursion in Middle Holocene Stalagmites from the Midwest" University of North Dakota Department

of Geology and Geological Engineering Leading Edge of Earth and Planetary Sciences Lecture Series, January 31, 2003.

"The Not-So-Isolated Climate of the Northern American Interior" University of Iowa Department of Geoscience Environmental Seminar, October 9, 2002.

"Paleo-precipitation and Vegetation Characteristics Deduced from Speleothems" University of Northern Iowa Earth Science Seminar, October 7, 2002.

"Isotopes in the Midwest and Mineralogy in Nepal: Two Different Approaches to Paleoclimate Reconstructions using Speleothems" Iowa State University

Department of Geology Guest Speaker Series, November 30, 2001.

"Understanding Climatic Change using Speleothem Mineralogy, Growth Rates, and Stable Isotopic Compositions" University of Northern Iowa Department of

Geography, Geomorphology Course Guest Lecture, April 24, 2001.

ÒHolocene Shifts in Speleothem Isotopic Compositions and their Paleoenvironmental ImplicationsÓ American Quaternary Association (AMQUA) Meeting,

Fayetteville, Arkansas, May 2000.

"The Use of Speleothems in Paleoclimatic Reconstruction" University of Iowa Department of Geoscience Weekly Seminar, May, 2000.

ÒStalagmites, Caves, and Climate ChangeÓ University of Iowa Afternoon with a Scientist Speaker Series, Iowa City, Iowa, April 13, 1999.

ÒGreat Basin Speleothems: A Way to Test Milankovitch Cyclicity?Ó Cornell College, Mt. Vernon, Iowa, January 31, 2000.

 

Grants

Organization

Title

Date

Amount

Iowa Science Foundation

Establishing Growth Histories for Stalagmites from Blanchard Springs Caverns, Northcentral Arkansas as a First Step Toward Paleoenvironmental Reconstructions

2006
$5,000
Cornell College
Faculty Development Grants: Student/Faculty Research in Portugal
2006
$4,500
Cornell College
Campbell R. McConnell Sabbatical Fellowship
2006-07
$15,000

Associated Colleges of the Midwest

Faculty Careers Enhancement Project: Construction of a 50,000 Year Paleoclimate Record for the Nazare Region, Portugal
2006
$3,000
Iowa Science Foundation
Reconstructing Late Pleistocene Vegetation Change in the Ozarks using Stalagmites from Cosmic Caverns, Arkansas
2005
$5,000
Cornell College
Faculty Development Grants: Student/Faculty Research at the University of New Mexico
2005
$5,500

Cornell College

Faculty Development Grant: Student/Faculty Research at the University of New Mexico

 

2004

$3,500

Petroleum Research Fund

Dominican Republic Corals As High-Resolution Records Of Shallow Marine Paleoenvironmental Conditions Prior To Closure Of The Panamanian Seaway

 

2004-06

$35,000

Iowa College Foundation

R.J. McElroy Student/Faculty Research Program:

Dominican Republic Coral Research

 

2003-04

$1,700

Cornell College

Faculty Development Grant: Student/Faculty Research at the University of Iowa and the Dominican Republic

 

2003

$3,500

Center for Global and Regional Environmental Research

 

Development of a High-Resolution Paleoclimate Data Set from New Zealand using Speleothem Growth Banding and Stable Isotopic Ratios

 

2002-03

$16,140

Iowa College Foundation

 

R.J. McElroy Student/Faculty Research Program: Midwestern Speleothem Research

 

2002-03

$1,745

Iowa Science Foundation

Reconstructing Shifts in Prairie and Deciduous Forest across the Central Midwest using Speleothems

 

2002-03

$4,000

Cornell College

Faculty Development Grant: Student/Faculty Research at the University of New Mexico

 

2002

$3,500

NSF

Acquisition of an Alpha Spectrometry System for Research and Undergraduate Training in Geology and Environmental Science (with B. Greenstein)

 

2001-02

$97, 826

NSF

Collaborative Research: Timing of Late Holocene Changes in Summer Indian Monsoon Intensity as Recorded in Mineralogic Changes in Speleothems, Pokhara Valley, Central Nepal

 

2000-02

$20,000

Geological Society of America; National Speleological Society; Sigma Xi; Nevada Bureau of Land Management; Richmond (VA) Area Speleological Society; University of Iowa

Various Grants for Dissertation Research

1995-00

$25,000

 

 

Professional Affiliations/Memberships

Geological Society of America

National Speleological Society

American Quaternary Association

Nepal Geological Society

Iowa Academy of Science

National Association of Geoscience Teachers

Center for Global and Regional Environmental Research

American Geophysical Union

Stewardship of Geological Societies

Chair, Geology Section, Iowa Academy of Science, 2003-2004

Vice-Chair, Geology Section, Iowa Academy of Science, 2002-2003

Committee on Preserves, Iowa Academy of Science, 2001-2002

Board of Directors, Geological Society of Iowa, 2001-present