Oxygen and silicon isotopes from diatoms (above) and other biogenic silica record important information about past environmental conditions.
Dr. Dodd in the Atacama Desert, Chile.
Salar de Llamara, Chile.
Graduate students Liz Olson and Marco Castillo collecting water samples in the Salar de Llamara.
Marco and high school students from Iquique, Chile collecting water samples.
Marco excavates a 9,000 yr old Prosopis tamarugo log.
Dr. Dodd collects a disk of Prosopis tamarugo for isotope analyses.
Sanded Prosopis tamarugo sample ready for ring width and isotope measurements.
Graduate student Vito Valerio with a sanded 2,500 yr old Prosopis tamarugo.
B.S., Beloit College, WI, 2003
M.S., University of Saskatchewan, 2006
Ph.D., University of New Mexico, 2011
My research focuses on applications of stable isotope geochemistry in a range of geological and environmental settings.
Oxygen and Silicon Isotopes in Biogenic Silica
Oxygen and silicon isotope values in biogenic silica (e.g. diatoms, sponge spicules, phytoliths) provide excellent records of paleoclimatic and paleohydrologic change in freshwater and marine locations. I currently have a number of active research projects aimed at developing records of past environmental change from the Pliocene through modern times in a number of terrestrial lakes and marine environments (including Antarctic marine sediment cores).
Diagenesis and Biogenic Silica
In order to understand the variations observed in biogenic silica from sedimentary records, it is necessary to quantify variables that can cause changes in the oxygen and silicon isotope values of biogenic silica during diagenesis (post-mortem alteration). My students and I are examining the effects of diagenetic conditions on the isotopic and structural composition in biogenic silica through laboratory experiments and natural calibration studies.
Holocene Water Availability in the Atacama Desert
Oxygen and carbon isotope variations in tree-ring cellulose record multiple climate variables (including source water, temperature, and relative humidity). We are working with Chilean geologists, dendrochronologists, and archeologists to develop a record of Holocene climate and water availability in the Atacama Desert of northern Chile using isotope variations in Prosopis tamarugo (similar to mesquite) trees that are well preserved for at least the past 10ka, and perhaps longer.
Groundwater in the Atacama
Geochemical and modeling based approaches to assessing groundwater recharge in the Pampa del Tamarugal Basin, Atacama Desert, northern Chile (w/ Dr. Pollyea, Virginia Tech).
* Student research supervised by Dodd
Abbott, T.A.*, Dodd, J.P., Hackett, H.*, Scherer, R., Frank, T., Powell, R., in prep., Cryogenic brine formation in the Pliocene Ross Embayment, Antarctica. To be submitted to Geology.
Olson, E.J.*, Dodd, J.P., Rivera, M., in review, Eastern Pacific ENSO strength over the past 9500 years recorded by tree ring oxygen isotopes from the Atacama Desert of Northern Chile. Submitted to Geophysical Research Letters.
Dodd, J.P., Weidenheft, W.*, Schwartz, J.*, revisions pending Dehydroxylation and Diagenetic Variations in Diatom Oxygen Isotope Values. Geochimica et Cosmochimica Acta.
Jayne, R.S.*, Pollyea, R.M., Dodd, J.P., Olson, E.J.*, Swanson, S.K., 2016, Regional-scale groundwater flow in the Pampa del Tamarugal Basin, Atacama Desert, Chile.Hydrogeology Journal. p. 1–17. DOI 10.1007/s10040-016-1454-3.
Rivera, M.A., and Dodd, J.P., 2013, Domesticando el Desierto. Medio Ambiente y Ocupaciones Humanas en Ramaditas Desierto de Atacama (Taming the desert. Environment and human occupationsin Ramaditas, Atacama Desert). Dialogo Andino, v 41, 45-60.
Bojar, A.-V., Dodd, J.P., Seghedi, I., 2013, Isotope geochemistry (O, H and Sr) of Late Cretaceous volcanic rocks, Haţeg basin, South Carpathians, Romania. In Isotopic Studies in Cretaceous Research, eds. Bojar, A.-V., Melinte-Dobrinescu, M. C. and Smit, J. Geological Society of London, Special Publication. ISBN 978-1-86239-364-6.
Dodd, J.P., Sharp, Z.D., Fawcett, P.J., Brearley, A., and McCubbin, F.M., 2012, Rapid post-mortem maturation of diatom silica oxygen isotope values. Geochemistry, Geophysics, Geosystems, v. 13 (9), Q09014, doi:10.1029/2011GC004019.
Chapligin, B., Leng, M.J., Webb, E., Alexandre, A., Dodd, J.P., Lücke, A., Ijiri, A., Shemesh, A., Abelmann, A., Okazaki, T., Longstaffe, F., Herzschuh, A., Meyer, H., Moschen, R., Sharp, Z., Sloane, H.J., Sonzogni, C., Swann, G E.A., Sylvestre, F., Tyler, J.J., & Yam, R.., In press, Inter-laboratory comparison of oxygen isotopes from biogenic silica, Geochimica et Cosmochimica Acta. Available online 16 August 2011, ISSN 0016-7037, DOI: 10.1016/j.gca.2011.08.011. (http://www.sciencedirect.com/science/article/pii/ S0016703711004674)
Dodd, J.P., and Sharp, Z.D., 2010, A laser fluorination method for oxygen isotope analysis of biogenic silica and a new oxygen isotope calibration of modern diatoms in freshwater environments, Geochimica et Cosmochimica Acta, 74 (4): 1381-1390, (DOI 10.1016/j.gca.2009.11.023).
Schiff, C.J., Kaufman, D.S., Wolfe, A.P., Dodd, J.P., and Sharp, Z.D., 2009, Late Holocene storm-trajectory changes inferred from the oxygen isotope composition of lake diatoms, south Alaska. Journal of Paleolimnology, 41(1): 189-208 (DOI 10.1007/ s10933-008-9261-z).
Dodd, J.P., Patterson, W.P., Holmden, C., Brasseur, J.M., 2008. Robotic micromilling of tree rings: a new tool for obtaining subseasonal environmental isotope records. Chemical Geology, 252(1-2) 21-30. DOI 10.1016/j.chemgeo.2008.01.021.
Demystifying the IODP Proposal Process for Early Career Scientists. PI, Chris Lowery, Co-PIs A.J. Fraass, J.P. Dodd, M.O. Patterson, J. Coenen. Workshop scheduled for January 22 – 25 2017, Austin, TX. $40,000.
Diatom and Oxygen Isotope Evidence of Pliocene Antarctic Ice Sheet Dynamics and Ross Sea Paleoceanography (Grant No. 1443420). Dodd – PI. Co-PI R.P. Scherer and J.P. Warnock. NSF-PLR Antarctic Earth Sciences. 08/2015 – 07/2017. $211,337.
Silicon isotopes in biogenic silica as a novel proxy for exploring carbon cycle dynamics throughout the Cenozoic. Pending. American Chemical Society, Petroleum Research Fund – Doctoral New Investigator Grant. $100,000. 6/2014 – 8/2016.
Holocene Climate Variability, Water Resource Availability, and Human Settlement in the Atacama Desert, Chile from Oxygen Isotope Values in Tree-Ring Cellulose. Pending. National Geographic Society, Waitt Grant. $12,000. 12/2013 – 12/2014.
Stable Isotope and Geochemical Approach to Regional Hydrologic Variability in the northern Atacama, Chile. 2013 Summer Research & Artistry Grant, Northern Illinois University. $15,000. 5/2013 – 5/2014
The Role of Groundwater in the Flooding History of Clear Lake, Wisconsin, Co-PI w/ S. K. Swanson (Beloit), Keck Geology Consortium, NSF-REU Award: 1062720, Department of Defense, the Keck Member Schools, and the ExxonMobil Foundation. $40,000. 01/2012 to 05/2013.
Climate and Precipitation Variability in the Yucatán Peninsula, Mexico and the Atacama Desert, Chile from Oxygen Isotope Values in Tree-Ring Cellulose, 2012 Summer Research & Artistry Grant, Northern Illinois University. $15,000. 5/2012 – 5/2013.
* student research supervised by Dodd
Abbott, T.*, Dodd, J.P., Findley, M.*, and Scherer, R.P., 2016, Cryogenic brine formation in the Ross Sea Recorded by diatom silica oxygen isotope values from a Pliocene marine sediment core. Geological Society of America Annual Meeting, Denver, CO, Paper No. 43-5.
Lehman, A.D.*, Dodd, J.P., 2016, The effects of MG, AL, FE, and CA on diagenetically induced phase changes in biogenic opal-A: implications for diatom silica as a paleoenvironmental proxy. Geological Society of America Annual Meeting, Denver, CO, Paper No. 15-2.
Abbott, T.*, Dodd, J.P., Hackett, H.*, and Scherer, R.P., 2016, A First Look at Oxygen and Silicon Isotope Variations in Diatom Silica from a Pliocene Antarctic Marine Sediment Core. American Geophysical Union Ocean Sciences Meeting 2016; PC54A-2214.
Pryer, A.*, Dodd, J.P., 2016, The Effects of Mg and Al on Diagenetically Induced Phase Changes in Biogenic Opal-A: Implications for Biogenic Silica as Paleoenvironmental Proxy. American Geophysical Union Ocean Sciences Meeting 2016; PC54A-2215.
Olson, E.J.*, Dodd, J.P., 2015, Spatial and temporal variation in tree-ring α-cellulose oxygen andhydrogen isotope values as a record of water availability in the Atacama Desert. American Geophysical Union Fall Meeting 2015; PP14A-05.
Dodd, J.P., Freimuth, E.*, Olson, E.J.*, Diefendorf, A.F., 2015, Oxygen isotope values of tree ring α-cellulose as a proxy of hydroclimate variability in arid regions. American Geophysical Union Fall Meeting 2015; PP14A-04.
Jayne, R.S.*, Dodd, J.P., Pollyea, R.M., 2015, Assessing groundwater recharge mechanisms in the Pampa del Tamarugal Basin of northern Chile's Atacama Desert: American Geophysical Union Fall Meeting 2015, H51D-1399.
Rivera, M.A., Olson, E.J*, Dodd, J.P., 2015, Domesticando el Desierto. Medio Ambiente y Ocupaciones Humanas en Ramaditas 20th Congress of Chilean Archaeology, University of Concepcion.
Fortney, C.*, Stansell, N., Klein, E., Terasmaa, J., Dodd, J.P., 2015, Stable isotope record of Holocene precipitation changes from Lake Nuudsaku in southern Estonia. EGU General Assembly 2015; EGU2015-7329, vol. 17.
Wiedenheft, W.*, Dodd, J.P., Sunderlin, L. Rapid changes in diatom silica surface charge density, silanol abundance, and oxygen isotope values elucidate silica maturation processes in biogenic silica. American Geophysical Union Fall Meeting 2014; B51A-0008.
Dodd, J.P., Pollyea, R. Combining numerical modeling and stable isotope values to quantify groundwater recharge from the Chilean Andes to the Pampa del Tamarugal Basin, Atacama Desert, northern Chile. American Geophysical Union Fall Meeting 2014; H31A-0583.
Olson, E.J.*, Dodd, J.P., Rivera, M.A., 2014, Holocene Water Availability in the Atacama Desert as Recorded by Seasonal Tree Ring Oxygen Isotope Variations: Goldschmidt Conference, Sacramento, CA (Gold2014:abs:2732)
Olson, E.J.*, Dodd, J.P., Rivera, M.A., 2014, Water Availability at the 2.5ka Archeological Site, Ramaditas, in the Atacama Desert. IGBP-PAGES 2k 3rd International Symposium South and Central America (LOTRED-SA), Climate Change and Human Impact in Central and South America over the Last 2000 Years: Observations and Models, July 9-11, 2014, Medellín. Colombia.
Dodd, J.P., Olson*, E.J., Rivera, M.A., 2014, Holocene water availability in the northern Atacama Desert as recorded by oxygen isotope variations in Prosopis tamarugo: 9th International Conference on Dendrochronology, Melbourne, Australia.
Van Dussen*, E.W., Fischer, M.P., Pollyea, R.M., and Dodd, J.P., 2013, The role of geometry and internal structures on fluid system evolution in narrowly tapered orogenic wedges: Americam Association of Peterolium Geologists and Society of Exploration Geophysicists Annual Student Expo. Houston, TX.
Hackett*, H., Dodd, J.P., 2013, Preliminary insights from an isotope study on an Antarctic Pliocene diatomite: 4th International Polar Marine Diatom Workshop, Cardiff, UK.
Craig*, A. Creamer, W., Dodd, J.P., 2013, The application of organic residue analysis to archeological ceramics: a study of Andean vessels: 41 Midwest Conference on Andean and Amazonian Archaeology and Ethnohistory. Northern Illinois University, Dekalb, Illinois.
Brokus*, S.A., and Dodd, J.P., 2013, A hydrological investigation of groundwater and surface water geochemistry in the Atacama Desert of northern Chile: 41 Midwest Conference on Andean and Amazonian Archaeology and Ethnohistory. Northern Illinois University, Dekalb, Illinois.
Swanson, S.K., Dodd, J.P., 2013, The Role of Groundwater in the Flooding History of Clear Lake, Wisconsin. Proceedings of the 26 Annual Keck Research Symposium in Geology.
Icks*, N.,F. Dodd, J.P., 2013, Sedimentological evidence of a persistent ground-water dominated systin in Duck Lake, WI over the past 8000 years. Proceedings of the 26 Annual Keck Research Symposium in Geology.
Swanson, S.K., Dodd, J.P., Chew*, B., Graham*, G., Honorof*, L., Icks*, N., Karr*, N., LaBriola*, C., 2013, The role of groundwater in the flooding history of Clear Lake, Wisconsin: 37th Annual Meeting AWRA-Wisconsin Section, Milwaukee, WI.
Bojar, A.V., Dodd, J.P., Seghedi, I., 2013, Isotope geochemistry of Late Cretaceous volcanic rocks, Hateg basin, South Carpathians, Romania: Geophysical Research Abstracts, EGU General Assembly, v. 15, EGU2013-5716-1.
Dodd, J.P., Rivera, M.A., 2012,Variations in groundwater availability during the past 9,000 years in the Atacama Desert, Chile: A subannual record of oxygen isotope values from Prosopis tamarugo tree rings: EOS Transactions, American Geophysical Union, v. 93, H53A-1509.
Rivera, M.A., Dodd, J.P., & Shea, D.E., 2012, Water Availability during Prehispanic Human Settlement in the Atacama Desert: 40th Annual Midwest Conference on Andean and Amazonian Archaeology and Ethnohistory, Field Museum, Chicago, IL.
Dodd, J.P., Fawcett, P.J., & Sharp, Z.D., 2011, Rapid onset and collapse of the summer monsoon during interglacial and glacial periods MIS 11 and 12 as recorded by diatom silica δ18O values from the Valles Caldera: EOS Transactions, American Geophysical Union, v. 92, PP21A-1783.
Fawcett, P.J., Brown, E.T., Werne, J.P., Contreras, S., Anderson, R.S., Dodd, J.P., Sharp, Z.D., Heikoop, J.M., & Allen, C.D., 2011, Millennial-scale climate variability during a mid-Pleistocene glacial (MIS 12) from a terrestrial lacustrine record in the Valles Caldera, New Mexico: EOS Transactions, American Geophysical Union, v. 92.
Ziegler, K., Dodd, J.P., Sharp, Z.D., Brearley, A.J., Young, E.D., 2011, Silicon and oxygen isotopes: The maturation of lacustrine diatoms: Mineralogical Magazine, v. 75, p. 2284, Gold2011:abs:5675.