The CCGS Hudson in Lancaster Sound, the entrance to the NW
      Passage during a coring expediton in 2008 on which Dr. Ortiz

Last Glacial Maximum to Holocene Paleoclimate Change Research

Dr. Joseph D. Ortiz
Kent State University, Department of Geology

A significant thrust of the research in my lab is focused on understanding the mechanisms that drive climate change from the LGM through the Holocene on a global scale. Climate can be considered as the net result of the redistribution of heat from the tropics to the poles. How the heat is redistributed depends on the interplay of atmospheric and oceanic modes of variability, which exhibit different, inherent timescales depending on which process are involved and the geographic position of interest. To reconstruct processes operating on timescales ranging from decadal to millennial resolution requires high resolution proxies collected from locations with rapid accumulation rates. Much of my Holocene work is thus focused on marginal marine or lacustrine environments selected on the basis of their high sediment accumulation rates. I make extensive use of sediment physical properties measurements (visible derivative spectroscopy, laser particle size analysis, and elemental analysis by x-ray florescence) to reconstruct sediment provenance and climate variability through time. These methods are rapid, require little sample preparation and yield, rich, multivariate data sets that can be unmixed, or decomposed using statistical methods to partition variance related to how different processes have influenced a location through time. I have been instrumental in the development of visible derivative spectroscopy as a tool for paleoclimatic reconstruction. I also employ micropaleontological and stable isotope analysis of foraminifera as needed to answer questions about Holocene climate change. Although I am interested in global processes, I address these questions through detailed regional reconstructions and have worked in most of the World Ocean's major basins.

Apply online to the Graduate Program in Geology at Kent State University.

More information about the Kent State University Geology Graduate program.

My collaborative work on the 1500 year climate cycle has been highlighted by the National Science Foundation,
along with information about my contribution to the Holocene paleoclimate work on Soledad Basin.

Here are some papers you can read to learn about my colleagues and work:

L. Yi, S Chen, JD Ortiz, G Chen, J Peng, F Liu, Y Chen, C Deng, 1500-year cycle dominated Holocene dynamics of Yellow River delta, The Holocene, August 20  2015 (Published online before print August 20, 2015, doi: 10.1177/0959683615596834).

Lindsay CM, Lehman, SJ, Marchitto, TM, and JD Ortiz, The surface expression of radiocarbon anomalies near Baja California during deglaciation, EPSL 422 67–74, 2015.

Mihindukulasooriya, LN, Ortiz, JD, Pompeani, DP,  Steinman, BA,  and MB Abbott
, Reconstruction of late Quaternary paleohydrologic conditions in
southeastern British Columbia using visible derivative spectroscopy of Cleland Lake sediment, Quaternary Research, in press 2015

Nwaodua, E.C., and Ortiz, J.D., Application of quotient normalization technique to minimize errors in diffuse spectral reflectance data collected under various conditions, The Journal of Sedimentary Research, 84, 729-742, DOI: 10.2110/jsr.2014.57, 2014.

Nwaodua, E.C., and Ortiz, J.D., E.M. Griffith, Diffuse spectral reflectance of surficial sediments indicates sedimentary environments on the shelves of the Bering Sea and western Arctic, Marine Geology, 355, 218–233, DOI: 10.1016/j.margeo.2014.05.023 2014.

Steinman, B.A., Abbott, M.B., Mann, M.E., Ortiz, J.D., Finney, B., and Pompeani, D.P., Ocean-atmosphere forcing of hydroclimate in the Pacific Northwest on centennial timescales, Geophysical Research Letters, DOI: 10.1002/2014GL059499, 2014.

Jennings, A.E., Walton, M.E., O ́Cofaigh, C., Kilfeather, A., Andrews, J.T., Ortiz, J.D., deVernal, A., and J.A. Dowdeswell, Paleoenvironments during Younger Dryas-Early Holocene retreat of the Greenland Ice Sheet from outer Disko Trough, central west Greenland, J. Quaternary Sci., DOI: 10.1002/jqs.2652, 2014.

Ranasinghe, P.N., Ortiz, J.D., Moore, A.L, McAdoo, B., Wells, N., Siriwardana, C.H.E.R, Wijesundara, D.T.D.S., Mid–Late Holocene coastal environmental changes in southeastern Sri Lanka: New evidence for sea level variations in southern Bay of Bengal, Quaternary International, 2013, doi: 10.1016/j.quaint.2013.02.030

Ranasinghage, P. N., Ortiz, J.D., Smith, A.J., Griffith, E.M., Siriwardana, C.H.E.R, De Silva, S.N., and Wijesundara, D.T.D.S., 2013, Mid- to late-Holocene Indian winter monsoon variability from a terrestrial record in eastern and southeastern coastal environments of Sri Lanka, The Holocene, DOI: 10.1177/0959683612475141.

Darby, D.A., J.D. Ortiz, C. E.Grosch, S. P. Lund, 2012, 1,500 year cycle in the Arctic Oscillation identified in Holocene Arctic sea-ice drift, Nature Geosci., 5, 897–900, Advance Online Publication: 11/11/2012, (doi: 10.1038/NGEO1629).

Bouchard, F., Pienitz, R., Ortiz, J.D., Francus P., and I. Laurion, 2012, Paleolimnological conditions inferred from fossil diatom assemblages and derivative spectral properties of sediments in thermokarst ponds of subarctic Quebec, Canada, Boreas, Early View first published online: 3 Dec 2012, DOI: 10.1111/bor.12000

Ortiz, J.D., Nof, D., Polyak, L., St. Onge, G., Lise-Pronovost, A., Naidu, S., Darby, D., and Brachfeld, S. 2012: The Late Quaternary flow through the Bering Strait has been forced by the Southern Ocean Winds. JPO, 42(11), 2014-2029, Early online release: 7/19/2012, (doi: 10.1175/JPO-D-11-0167.1).

Nof, D., Zharkov, V., Ortiz, J.D., Paldor, N. and E. Chassignet, 2012, The arrested Agulhas retroflection, J. Mar. Res., 69, (Stern Vol. Special Issue), 659-691.

Ortiz, J.D., Application of Visible/near Infrared derivative spectroscopy to Arctic paleoceanography, IOP Conf. Series: Earth and Environmental Science 14, 2011, 012011 doi:10.1088/1755-1315/14/1/012011, (

Nelson, D.B., Abbott, M.B., Steinman, B., Polissar, P.J. Stansell, N.D., Ortiz, J.D., Rosenmeier, M.F., Finney, B.P., and Riedel, J., 2011, Drought variability in the Pacific Northwest from a 6,000-yr lake sediment record, PNAS,

Marchitto, T.M., Muscheler, R., Ortiz, J.D., Carriquiry, J., and A. van Geen, 2010, Dynamical response of the tropical Pacific Ocean to solar forcing during the early Holocene, Science, 330, 1378-1381, DOI: 10.1126/science.1194887

Lei, X., Ling, D., Mei-Xum, Z., Zhang, R.-P., van Geen, A. and Ortiz, J.D., Centennial variations in Sea surface temperature and productivity over the last 14ka from core PC14 off Baja California, [In Chinese with English Abstract], Oceanologica et Limnologia Sinica, 40, 385-392, 2009.

Ortiz, J.D., Polyak, L., Grebmeier, J.M., Darby, D.A., Eberl, D.D., Naidu, S., Nof, D., Provenance of Holocene sediment on the Chukchi-Alaskan margin based on combined diffuse spectral reflectance and quantitative X-Ray Diffraction analysis. Global and Planetary Change, (68), 73-84, 2009.

Darby, D.A., Ortiz, J.D., Polyak, L., Lund, S., Jakobsson, M., Woodgate, R.A., The role of currents and sea ice in both slowly deposited central Arctic and rapidly deposited Chukchi-Alaskan margin sediments, Global and Planetary Change, (68), 58-72, 2009.

Brachfeld, S., Barletta, F., St-Onge, G., Darby, D.A., Ortiz, J.D., Detrital and diagenetic magnetic signatures of sediment supply and water column stratification in Holocene sedimentary records from the eastern Chukchi Sea. Global and Planetary Change, (68), 100-114, 2009.

Ortiz, J.D. and O’Connell, S., Toward a non-linear grayscale calibration method for legacy photographic collections, in P. Francus, J. Thurow, (eds.) Developments in Paleocenvironmental Research Series: Image Analysis, sediments and paleoenvironmental Reconstruction, 125-137, 2004.

Peteet, D., Beck, W., Ortiz, J.D. O’Connell, S, Kurdyla, D., and Mann, D. Rapid Vegetational and Sediment Change from Rano Aroi Crater, Easter Island, in Easter Island, Scientific Exploration into the World's Environmental Problems in Microcosm J. Loret and J.T. Tanacredi, Eds., Kluwer, Academic/Plenum Publishers, NY, 79-89, 2003.

Ortiz, J.D., Mix, A.C., Wheeler, P.A., and R.M. Key, Anthropogenic CO2 invasion into the northeast Pacific based on concurrent δ13CDIC and nutrient profiles from the California Current, Global Biogeochemical Cycles, 14, 917-929, 2000.

deMenocal, P., Ortiz, J.D., Guilderson, T., and M. Sarnthein, Coherent high- and low-latitude Climate Variability during the Holocene Warm Period, Science, 288, 2198-2202, 2000.

deMenocal, P., Ortiz, J.D., Guilderson, T., Adkins, J., Sarnthein, M., Baker, L., and M. Yarusinsky, Abrupt onset and terminations of the African Humid Period: Rapid climate responses to gradual insolation forcing, Quaternary Science Reviews, 19, 347-361, 1999.

Ortiz, J. D. and F. R. Rack, Non-invasive sediment monitoring methods: Current and future tools for high-resolution climate studies, in Reconstructing Ocean History: A window into the future, Kluwer, New York, 343-380, 1999.

Ortiz, J.D., and A.C. Mix, Comparison of Imbrie-Kipp transfer function and Modern Analog Temperature estimates using sediment trap and coretop foraminiferal faunas, Paleoceanography, 12, 175-190, 1997.

Ortiz, J.D., Mix, A.C., Hostetler, S., and M. Kashgarian, The California Current of the Last Glacial Maximum at 42oN: Reconstruction based on multiple proxies, Paleoceanography, 12, 191-206, 1997.

Ortiz, J.D., Mix, A.C., Rugh, W., Watkins, J.M., and R.W. Collier, Deep-dwelling planktonic foraminifera of the Northeast Pacific reveal environmental control of oxygen and carbon isotopic disequilibria, Geochimica et Cosmochimica Acta, 60, 4509-4523, 1996.

Ortiz, J.D., Mix, A.C., and R.W. Collier, Environmental control of living symbiotic and asymbiotic foraminifera of the California Current, Paleoceanography, 10, 987-1009, 1995.

Ortiz, J.D., and A.C. Mix, The spatial distribution and seasonal succession of planktonic Foraminifera in the California Current System off Oregon, September 1987-September 1988, in Upwelling Systems: Evolution since the early Miocene, Geological Society Special Publication No. 64, C.P. Summerhays, C.P., Prell W., and Emeis, K.C., (Eds.), London, 1992.