My research is in stratigraphic and paleoenvironmental synthesis, using the stable carbon & oxygen isotopic geochemistry of carbonates and fossil material, and the carbon isotopic composition of organic matter in the stratigraphic rock record. Recently, this work has been at the state-of-the-art Keck Paleoenvironmental & Environmental Stable Isotope Laboratory at the University of Kansas, using a Finnigan Kiel III automated carbonate reaction device, and a dual-inlet Finnigan MAT 253 stable isotope ratio mass spectrometer, and a Costech Elemental Analyzer coupled to a continuous-flow Finnigan MAT 253 mass spectrometer. Work has been focused on Cretaceous, Neogene, and Ordovician global change studies that have received external peer-reviewed grant support.
February 2005 Geology cover. Thin section photomicrograph of sphaerosiderites from the Cretaceous Dakota Formation. Photo by Tim White; cover design by Margo Y. Sajban, Geological Society of America.
Philosophical Approach to Paleoclimatology
Paleoclimatology bestows a special claim for social relevance on the geosciences in helping to improve forecasting of impending climate changes forced by the buildup of greenhouse gases in the atmosphere over the next two centuries. Terrestrial paleoclimatology remains a research frontier, having lagged earlier studies of marine records spurred by the DSDP and ODP programs. Nevertheless, paleoclimatic studies of terrestrial environments are more directly relevant to the human prospect attending future climate changes. Studies of high-resolution Quaternary paleoclimatic records from continental archives in ice cores, lacustrine sediments, tree rings, and spleleothems represent a burgeoning area of paleoclimatic research. While I have followed development of this work, my funded paleoclimatologic research has been in other periods of Earth History. Given that a 4 x CO2 atmosphere is probably removed by less than two centuries from now, the terrestrial paleoclimatology of Mesozoic warm periods in Earth History, with special emphasis on major uncertainties regarding the response of the hydrologic cycle, has been the niche in paleoclimatic research that I have elected to fill. My research team is recognized for international leadership in this research frontier, and has been successful in attracting major grant support for this work. The development of the sphaerosiderite paleoclimate proxy (see February 2005 cover of Geology Magazine; seminal work published by Ludvigson et al., 1998) has been one of our major innovations.
This team research was recently awarded its third major grant from NSF. Our work has investigated δ18O compositions of paleosol carbonates from the paleoequator to 75°N paleolatitude, and determined that differences between the Cretaceous gradient and that predicted from modern soil waters result from a much more active hydrologic cycle in the Cretaceous. Isotope mass balance modeling suggests up to a four-fold increase in Cretaceous precipitation rates at the mid-latitude high (45°N). The most recent grant involves studies of modern sites where pedogenic siderite (FeCO3) is forming, with the goal of empirically testing our ancient sphaerosiderite paleoclimate proxy, one that was originally based on theoretical applications of published laboratory experiments.
A long-term research venture concerns the δ13C chemostratigraphy of stacked Early Cretaceous calcrete paleosols in dinosaur-bearing strata of the Cedar Mountain Formation in Utah. Pilot studies showed that these deposits capture the record of marine carbon isotope excursions associated with Oceanic Anoxic Events 1a, 1b, and 1d in the Aptian-Albian stages. Diagenetic studies of individual beds are tracking changes in the δ18O values of paleoprecipitation, and 18O enrichments in vadose components are being used to develop quantitative estimates of evaporative fluxes from these semiarid paleolandscapes. Colleagues and I are carrying out multi-proxy paleoenvironmental studies of bone beds in the Cedar Mountain Formation, integrating diagenetic work on authigenic carbonates with phosphate δ18O data from fossil tooth enamel from theropods, sauropods, turtle scutes, and other taxa in bone beds. Future plans include the possible integration of magnetostratigraphy with isotopic chemostratigraphy for refined marine-nonmarine correlations. I am also involved in collaborative research using radiogenic isotopes to date pedogenic carbonate components.
Ufnar, D.F., Ludvigson, G.A., González, L.A., and Gröcke, D.R., 2008, Precipitation rates and atmospheric heat transport during the Cenomanian greenhouse warming in North America: Estimates from a stable isotope mass-balance model: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 266, p. 28-38. [PDF]
Phillips, P.L., Ludvigson, G.A., Joeckel, R.M., González, L.A., Brenner, R.L., and Witzke, B.J., 2007, Sequence stratigraphic controls on synsedimentary cementation and preservation of dinosaur tracks: Example from the lower Cretaceous, (Upper Albian) Dakota Formation, southeastern Nebraska: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 246, p. 367-389. [PDF]
Gröcke, D.R., Ludvigson, G.A., Witzke, B.J., Robinson, S.R., Joeckel, R.M., Ufnar, D.F., and Ravn, R.L., 2006, Recognizing the Albian-Cenomanian (OAE1d) sequence boundary using plant carbon isotopes: Dakota Formation, Western Interior Basin, USA: Geology, v. 34, no. 3, p. 193-196. [PDF].
Ufnar, D.F., González, L.A., Ludvigson, G.A., Brenner, R.L., Witzke, B.J., and Leckie, D., 2005, Reconstructing a mid-Cretaceous landscape from paleosols in western Canada: Journal of Sedimentary Research, v. 75, no. 6, p. 984-996. [PDF]
White, T.S., Witzke, B.J., Ludvigson, G.A., and Brenner, R.L., 2005, Distinguishing base-level change and climate signals in a Cretaceous alluvial sequence: Geology, v. 33, no. 1, p. 13-16. [PDF].
Ufnar, D.F., González, L.A., Ludvigson, G.A., Brenner, R.L., and Witzke, B.J., 2004, Evidence for increased latent heat transport during the Cretaceous (Albian) greenhouse warming: Geology, v. 32, no. 12, p. 1049-1052. [PDF].
Ufnar, D.F., González, L.A., Ludvigson, G.A., Brenner, R.L., and Witzke, B.J., 2004, Diagenetic overprinting of the sphaerosiderite paleoclimate proxy: are records of pedogenic groundwater δ18O values preserved?: Sedimentology, v. 51, no. 1, p. 127-144. [PDF]
Ufnar, D.F., Ludvigson, G.A., González, L.A., Brenner, R.L., and Witzke, B.J., 2004, High latitude meteoric δ18O compositions: Paleosol siderite in the mid-Cretaceous Nanushuk Formation, North Slope Alaska: Geological Society of America, Bulletin, v. 116, no. 3, p.463-159. [PDF]
Brenner, R.L., Ludvigson, G.A., Witzke, B.J., Phillips, P.L., White, T.S., Ufnar, D.F., González, L.A., Joeckel, R.M., Gottemoeller, A., and Shirk, B.R., 2003, Aggradation of gravels in tidally influenced fluvial systems: upper Albian (Lower Cretaceous) on the cratonic margin of the North American Western Interior foreland basin: Cretaceous Research, v.24, no. 4, p. 439-448. [PDF]
Ufnar, D.F., González, L.A., Ludvigson, G.A., Brenner, R.L., and Witzke, B.J., 2002, The mid-Cretaceous water bearer: Isotope mass balance quantification of the Albian hydrologic cycle: Palaeogeography, Palaeoclimatology, Palaeoecology v. 188, p. 51-71. [PDF]
Ufnar, D.F., Gonzalez, L.A., Ludvigson, G.A., Brenner, R.L., and Witzke, B.J., 2001, Stratigraphic implications of meteoric sphaerosiderite δ18O compositions in paleosols of the Cretaceous (Albian) Boulder Creek Formation, NE British Columbia foothills, Canada: Journal of Sedimentary Research, v. 71, no. 6, p. 1017-1028. [PDF]
White, T.S., González, L.A., Ludvigson, G.A., and Poulsen, C.J., 2001, Middle Cretaceous greenhouse hydrologic cycle of North America: Geology, v. 29, no. 4, p. 363-366. [PDF]
White, T.S., Witzke, B.J., and Ludvigson, G.A., 2000, Evidence for an Albian Hudson arm connection between the Cretaceous western interior seaway of North America and the Labrador Sea: Geological Society of America, Bulletin, v. 112, no. 9, p. 1342-1355. [PDF]
Ludvigson, G.A., González, L.A., Metzger, R.A., Witzke, B.J., Brenner, R.L., Murillo, A.P., and White, T.S., 1998, Meteoric sphaerosiderite lines and their use for paleohydrology and paleoclimatology: Geology, v. 26, p. 1039-1042. [PDF]
I am involved in new collaborative research integrating nonmarine sequence stratigraphic, petrographic, and stable isotopic studies of authigenic carbonates from Neogene strata of the High Plains region, including the Ogallala Formation and younger deposits. These deposits are calibrated by volcanic ash bed chronology.
Ludvigson, G.A., Smith, J.J., Macfarlane, P.A., Mandel, R. Haj, A.E., Murphy, L., and McKee, A., 2008, Evidence for a regionally persistent carbon isotopic chemostratigraphy in the Neogene High Plains succession of western Kansas: Geological Society of America, Abstracts with Programs, v. 40, no. 5, p. 24. [Abstract].
Smith, J.J., Ludvigson, G.A., Macfarlane, P.A., Mandel, R., Haj, A., Murphy, L, and McKee, A., 2008, Carbon isotopic chemostratigraphy of Neogene strata in the High Plains succession of Kansas: Geological Society of America, Abstracts with Programs, v. 40, no. 6, p. 257-258. [Abstract].
This project was funded by NSF, and is an exploratory effort to examine the sequence stratigraphic architecture of a succession of marine carbon isotope excursions that are temporally associated with onset of a glacial episode in the southern hemisphere. Work has shown that positive carbon isotope excursions that occur in more nearshore carbonate strata completely starve out in more offshore sections. Dramatic δ18O shifts associated with some excursions might suggest relationships to oscillations in thermohaline circulation in the Iapetus Ocean. Work to date has been on the d13Ccarb of carbonate muds, but we are beginning work on the chemostratigraphy of bulk organic matter analyzed by EA-CF-IRMS. I also am interested in collaborative research coupling the light stable isotope chemostratigraphy with studies of other isotope systems to further general understanding of the record. Future collaborative research on paleoceanographic modeling of Ordovician epeiric seas is also a long-term goal.
Ludvigson, G.A., Witzke, B.J., Gonzalez, L.A., Carpenter, S.J., Schneider, C.L., and Hasiuk, F.H., 2004, Late Ordovician (Turinian-Chatfieldian) carbon isotope excursions and their stratigraphic and paleoceanographic signficance: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 210, no. 2-4, p. 187-214. [PDF]
Simo, J.A. Emerson, N.R., Byers, C.W., and Ludvigson, G.A., 2003, Anatomy of an embayment in an Ordovician sea, Upper Mississippi Valley, USA: Geology, v. 31, no. 6, p. 545-548. [PDF]
Ludvigson, G.A., Witzke, B.J., Schneider, C.L., Smith, E.A., Emerson, N.R., Carpenter, S.J., and González, L.A., 2000, A profile of the mid-Caradoc (Ordovician) carbon isotope excursion at the McGregor Quarry, Clayton County, Iowa; in, Anderson, R.R., Ed., The Natural History of Pikes Peak State Park, Clayton County, Iowa, Geological Society of Iowa, Guidebook 70, p. 25-31. [PDF]
Ludvigson, G.A., Jacobson, S.R., Witzke, B.J., and González, L.A., 1996, Carbonate component chemostratigraphy and depositional history of the Ordovician Decorah Formation, Upper Mississippi Valley; in, Witzke, B.J., Ludvigson, G.A., and Day, J.E., eds., Paleozoic Sequence Stratigraphy: Views from the North American Craton, Geological Society of America, Special Paper 306, p. 67-86. [PDF]
Raatz, W.D., and Ludvigson, G.A., 1996, Depositional environments and sequence stratigraphy of Upper Ordovician epicontinental deep water deposits, eastern Iowa and southern Minnesota; in, Witzke, B.J., Ludvigson, G.A., and Day, J.E., eds., Paleozoic Sequence Stratigraphy: Views from the North American Craton, Geological Society of America, Special Paper 306, p. 143-159. [PDF]
Kansas Geological Survey
Updated July 6, 2012
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