Last updated 20 November 2007
Diagenesis of Carbonate Rocks is my long-term interest. Some current research involves whether subtle unconformities in Ordovician limestones interpreted by Steven M. Holland (UGA's sequence stratigrapher) can be detected or confirmed by diagenetic studies using petrographic, isotopic, and trace elemental analysis. Some of this work was the subject of Jen Diaz's, Mike Jordan's, and Bethany Theiling's M.S. thesis work. I'm also interested in regional studies of diagenesis, like Ed Hood's M.S. thesis work, and in the mass transport problems that need to be answered at the basinal scale of diagenesis.
Railsback. L. Bruce, Layou, Karen M., Heim, Noel A., Holland, Steven M., Trogdon, M.L., Jarrett, M.B., Izsak, Gabriel M., Bulger, Daniel E., Wysong, Eric J., Trubee, Kenton S., Fiser, Julie M., Cox, Julia E., and Crowe, Douglas E., submitted, Geochemical evidence for meteoric diagenesis and cryptic surfaces of subaerial exposure in subtidal carbonates from the Upper Ordovician of the Nashville Dome, central Tennessee, U.S.A., in Ketzer, Marcelo, and Morad, Sadoon, eds., Linking Diagenesis to Sequence Stratigraphy of Sedimentary Rocks: International Association of Sedimentologists Special Publication.
Theiling, Bethany P., Railsback, L. Bruce, Holland, Steven M., and Crowe, Douglas E., 2007, Heterogeneity in geochemical expression of subaerial exposure in limestones, and its implications for sampling to detect exposure surfaces: Journal of Sedimentary Research, v. 77, p. 159-169.
Railsback, L. Bruce, Holland, Steven M., Hunter, Daniel E., Jordan, E. Michael, Diaz, Jennifer R., and Crowe, Douglas E., 2003, Controls on geochemical expression of subaerial exposure in Ordovician limestones from the Nashville Dome, Tennessee, U.S.A.: Journal of Sedimentary Research., v. 73, p. 790-805.
Railsback, L. Bruce, and Hood, Edward C., 2001, A survey of multi-stage diagenesis and dolomitization of Jurassic limestones along a regional shelf-to-basin transect in the Ziz Valley, Central High Atlas Mountains, Morocco: Sedimentary Geology, v. 139, p. 285-317.
Railsback, L. Bruce, 1999, Patterns in the compositions, properties, and geochemistry of carbonate minerals: Carbonates and Evaporites, v. 14, p. 1-20 (with an on-line appendix listing all known carbonate-bearing minerals).
Hunter, Daniel M., Holland, Steven M., and Railsback, L. Bruce, 1999, Testing for subaerial exposure at five Upper Ordovician sequence boundaries, Nashville Dome, Tennessee: Geological Society of America Abstracts with Programs, Southeastern Section, p. A22.
Hood, E.C., and Railsback, L.B., 1999, A diagenetic study of Jurassic limestones from the High Atlas Mountains, Morocco: Geological Society of America Abstracts with Programs, Southeastern Section, p. A21.
Baldini, J.U.L., Elkins, J.T., Gardiner, L.S., Hunter, D.M., Railsback, L.B., and Holland, S.M., 1998, Petrographic and geochemical evidence for meteoric diagenesis and a Type I sequence boundary in Ordovician limestones near Pulaski, Tennessee: Geological Society of America Abstracts with Programs, v. 30, p. 332.
Railsback, L. Bruce, Sheen, Shaw-Wen, Brook, George A. and Kelloes, Catherine, 1997, Criteria for recognition of replacement of aragonite by aragonite in carbonate diagenesis: evidence from Botswanan speleothems: Speleochronos, No. 8, p. 3-11.
Railsback, L. Bruce, 1993, Control of crystal shape and size on formation of twin lamellae in calcite: implications for deep burial diagenetic fabrics in limestones: Carbonates and Evaporites, v. 8, p. 156-162.
Railsback, L. Bruce, 1993, Stability of carbonate minerals: a thermodynamic perspective and its implications for carbonate petrology: Journal of Geological Education, v. 41, p. 12-14.
Railsback, L. Bruce, 1984, Carbonate diagenetic facies in the Upper Pennsylvanian Dennis Formation in Iowa, Missouri, and Kansas: Journal of Sedimentary Petrology, v. 54, p. 986-999.
Petrography and Geochemistry of Speleothems is a source of information about past climate change. Work on stalagmites from southern Africa with George A. Brook
of the UGA Geography Department suggests that variations in layer thickness and other petrographic clues in speleothems can record changes in at least rainfall. We're also developing an appreciation for the variability of the petrography of speleothem fabrics, and it looks like there's a lot more to learn. This work has been supported by NOAA and NSF and was the subject of Margaret Rafter's M.S. thesis. M.S. student James Baldini's thesis focused on relationships between drip rates and speleothem morphologies, and Joe Elkins's Ph.D. work investigated ways to extract more meaningful carbon isotopic compositions from speleothems.
James W. Webster, George A. Brook, L. Bruce Railsback, Hai Cheng, R. Lawrence Edwards, Clark Alexander, and Philip P. Reeder, 2007, Stalagmite evidence from Belize indicating significant droughts at the time of Preclassic Abandonment, the Maya Hiatus, and the Classic Maya Collapse: Palaeogeography, Palaeoclimatology, Palaeoecology.v. 250, p. 1-17.
Brook, George A., Ellwood, Brooks B., Railsback, L. Bruce, and Cowart, J.B., 2006, A 164 ka record of environmental change in the American Southwest from a Carlsbad Cavern speleothem: Palaeogeography, Palaeoclimatology, Palaeo-ecology, v. 237, p. 483-507.
Elkins, Joe T., and Railsback, L. Bruce, 2006, Evaluation of the effect of oven roasting at 340¡C, bleach, 30% H2O2, and distilled/deionized water on the d13C value of speleothem carbonate: Journal of Cave and Karst Studies, v. 68, p. 137-143.
Baldini, J.U.L., F. McDermott, F., Baker, A., Baldini, L.M., Mattey, D.P. and Railsback, L. Bruce, 2005, Biomass effects on stalagmite growth and isotope ratios: A 20th century analogue from Wiltshire, England: Earth and Planetary Science Letters, v. 240, p. 486-494.
Sheen, Shaw-wen, Brook, George A., Railsback, L. Bruce, and Thill, Jean-Claude, 2003, Stalagmite annual layer thickness as a proxy for ENSO and rainfall: Evidence from Drotsky's Cave, Botswana, in Desertification in the Third Millennium (eds. A.S. Alsharhan, W.W. Wood, A. Goudie, K.W. Glennie and E.M. Abdellatif), A.A. Balkema, p. 27-44.
Railsback, L. Bruce, Dabous, Adel A., Osmond, J.K., and Fleisher, C.J., 2002, Petrographic and geochemical screening of speleothems for U-series dating: an example from recrystallized speleothems from Wadi Sannur Cavern, Egypt: Journal of Cave and Karst Studies, v. 64, p. 108-116.
Railsback, L. Bruce, Brook, G.A., and Webster, J.W., 1999, Petrology and paleoenvironmental significance of detrital sand and silt in a stalagmite from Drotsky's Cave, Botswana: Physical Geography, v. 20, p. 331-347.
Brook, George A., Rafter, M.A., Railsback, L. Bruce, Sheen, Shaw-Wen, and Lundberg, Joyce, 1999, A high-resolution proxy record of rainfall and ENSO since A.D. 1550 from layering in stalagmites from Anjohibe Cave, Madagascar: The Holocene, v. 9, p. 695-705.
Railsback, L. Bruce, Sheen, Shaw-Wen, Rafter, Margaret A., Brook, George A. and Kelloes, Catherine, 1997, Replacement of aragonite by aragonite in carbonate diagenesis: Criteria for its recognition in speleothems from Botswana and Madagascar: Speleochronos, No. 8, p. 3-11.
Rafter, Margaret A., and Railsback, L. Bruce, 1996, Analysis of two Republic of Madagascar speleothems as potential records of climate: Geological Society of America Abstracts w. Programs, v. 28 p. A307.
Brook, G.A., Railsback, L.B., Cooke, J., Chen, J., and Culp, R.A., 1995, Precipitation data from annual growth layers in speleothems: some preliminary results from Drotsky's Cave in the Kalahari Desert of Botswana: Studia Carsologica, v. 6, p. 65-80.
Railsback, L. Bruce, Brook, George A., Chen, Jian, Kalin, Robert, and Fleisher, Christopher J., 1994, Environmental controls on the petrology of a Late Holocene speleothem from Botswana with annual layers of aragonite and calcite: Journal of Sedimentary Research, v. A64, p. 147-155.
Stylolites and Pressure Dissolution have been the subject of a lot of models and speculation, but there's been surprisingly little data collection and experimentation. My work aims to collect data that will lead to quantifiable generalizations about stylolites from which sound interpretation can be made, and to conduct simple experiments to understand the limits of the conditions under which pressure solution phenomena occur. One general hypothesis driving my recent experiments is that pressure dissolution requires little pressure, but that dissolution is the key to the process. My field work focuses on collection of samples for lab analysis, and the distribution of vertical ("tectonic") NW-SE trending stylolites in the undeformed Nashville Dome.
Lee, Michael, and Railsback, L. Bruce, Pressure dissolution features in Waulsortian carbonates from the Silvermines district, Ireland: implications for constraining the timing of mineralization in the Irish Orefield: in revision for Mineralium Deposita.
Railsback, L. Bruce, 2003, Stylolites, in Middleton, G.V., ed., Encyclopedia of Sediments and Sedimentary Rocks: Kluwer.
Railsback, L. Bruce, 1998, Evaluation of spacing of stylolites, and its implications for self-organization of pressure dissolution: Journal of Sedimentary Research, v. 68, p. 2-7.
Andrews, Lynn M., and Railsback, L. Bruce, 1997, Controls on stylolite development: morphologic, lithologic, and temporal evidence from bedding-parallel and transverse stylolites from the US Appalachians: Journal of Geology, v. 105, p. 59-73.
Railsback, L. Bruce, 1996, Stylolites in limestones that lacked significant primary aragonite: Bulletin de la Societe Geologique de France, t. 167, No. 1, p. 181-183.
Railsback, L. Bruce, and Andrews, Lynn M., 1995, Tectonic stylolites in the "undeformed" Cumberland Plateau of southern Tennessee: Journal of Structural Geology, v. 17, p. 911-915.
Railsback, L. Bruce, 1995, Tectonic stylolites perpendicular to modern stress in the "undeformed" Nashville Dome: evidence for Jurassic-to-recent intraplate tectonic compression: Geol. Soc. Amer. Abstracts w. Programs, v. 27, p. A-217.
Railsback, L. Bruce, 1993, Intergranular pressure dissolution and compaction in a Plio-Pleistocene grainstone buried no more than 30 meters: Shoofly oolite, southwestern Idaho: Carbonates and Evaporites, v. 8, p. 163-169.
Railsback, L. Bruce., 1993, Lithologic controls on morphology of pressure dissolution surfaces (stylolites and dissolution seams) in Paleozoic carbonate rocks from the mideastern United States: Journal of Sedimentary Petrology, v.63 p. 513-522.
Railsback, L. Bruce, 1993, Contrasting styles of chemical compaction in the Upper Pennsylvanian Dennis Formation in the Midcontinent region, U.S.A.: Journal of Sedimentary Petrology, v. 63, p. 61-72.
Railsback, L. Bruce, and Hood, Edward C., 1993, Vertical sutured contacts caused by intergranular pressure dissolution during tectonic compression in Jurassic limestones, High Atlas Mountains, Morocco: Geol. Soc. Amer. Abstracts w. Programs, v. 25, p. A162.
Acid Rain and Groundwater Geochemistry is an area of research interest that has partly arisen from my teaching of our environmentally-minded students. In my 1995 GLY 815 class, we did a class project surveying the major-element geochemistry of groundwaters in Georgia. The point was to look at groundwater geochemistry from a perspective cutting across geologic regions, from the Valley and Ridge to the Coastal Plain. The result has been published in Southeastern Geology (see below).
More recently, I've been taking acid rain samples at short time intervals within showers and thunderstorms and finding that there's a surprising relationship of pH and lightning. Further work may involve chemical analysis of such samples to see what (H2SO4? HNO3?) causes the increased acidity of samples associated with lightning, or it could involve a network of sampling sites as storms move across north Georgia to see how acid precipitation varies geographically in response to changing sources of pollutants and changing meteorological conditions.
Railsback, L. Bruce, 1997, Lower pH of acid rain associated with lightning: Evidence from sampling within 14 showers and storms in the Georgia Piedmont in summer 1996: Science of the Total Environment, v. 198, p. 233-241.
Railsback, L. Bruce, Bouker, Polly A., Feeney, Thomas P., Goddard, Ethan A., Goggin, Keith E., Hall, A. Shawn, Jackson, Brian P., McLain, Angela A., Orsega, Michael C., Rafter, Margaret A., and Webster, James W., 1996, A survey of the major-element geochemistry of Georgia groundwater: Southeastern Geology, v. 36, No. 3, p. 99-102.
Global Change as Recorded in Sedimentary Rocks is a diverse area in which I've done modeling and collected isotopic and petrographic data. My research is seemingly drifting away from this area, although the speleothem work described above is an extension of it by another name. Julia Cox's M.S. project used Devonian pedogenic carbonates in the Devonian Catskill delta to constrain the CO2 content of the Devonian atmosphere.
Baldini, Lisa .M., Walker, Sally E., Railsback, L. Bruce, Baldini, James U.L., and Crowe, Douglas .E., 2007, Isotopic ecology of the modern land snail Cerion, San Salvador Bahamas: Preliminary advances toward establishing a low-latitude island palaeoenvironmental proxy: Palaios, v. 22, p. 174-187.
Cox, Julia E., Railsback, L. Bruce, and Gordon, E.A., 2001, Evidence from Catskill pedogenic carbonates for a rapid Late Devonian decrease in atmospheric carbon dioxide concentrations: Northeastern Geology and Environmental Science, v. 23, p. 91-102.
Railsback, L. Bruce, 1997, Comment on "d18O values of mudrocks: More evidence for an 18O-buffered ocean" by L.S. Land and L.F. Lynch, Jr.: Geochimica et Cosmochimica Acta, v. 62, p. 325-326.
Railsback, L. Bruce, 1995, Geological controls on global rates of coal deposition: A numerical model and its geochemical implications, in Haq, B.U., ed., Sequence Stratigraphy and Depositional Response to Eustatic, Tectonic, and Climatic Forcing: Dordrecht, Kluwer Academic Press p. 137-159.
Railsback, L. Bruce, 1993, Original mineralogy of Carboniferous worm tubes: Evidence for changing marine chemistry and biomineralization: Geology, v. 21, p. 703-706.
Railsback, L. Bruce, 1992, A geological numerical model for Paleozoic global evaporite deposition: Journal of Geology, v. 100, p. 261-277.
Woo, K.-S., Anderson, T.F., Railsback, L.B., and Sandberg, P.A., 1992, Oxygen isotope evidence for high-salinity surface seawater in the Mid-Cretaceous Gulf of Mexico: implications for warm, saline deepwater formation: Paleoceanography, v. 7, p. 673-685.
Railsback, L. Bruce, 1989, Sea level, episodic dolomitization, and temporal trends in non-skeletal carbonate mineralogy: Geol. Soc. Amer. Abstracts w. Programs, v. 21, p. A139.
Railsback, L. Bruce, and Anderson, Thomas F., 1987, Control of Triassic seawater chemistry and temperature on the evolution of post-Paleozoic aragonite-secreting faunas: Geology, v. 15, p. 1002-1005.
Railsback, L. Bruce, Anderson, Thomas F., Ackerly, Spafford C., and Cisne, John L., 1989, Paleoceanographic modeling of temperature-salinity profiles from stable isotope data: Paleoceanography, v. 4, 585-591.
Railsback, L. Bruce, Ackerly, Spafford C., Anderson, Thomas F., and Cisne, John L., 1990, Paleontological and isotope evidence for warm saline deep waters in Ordovician oceans: Nature, v. 343, p. 156-159.
Railsback, L. Bruce, 1990, Influence of changing deep ocean circulation on the Phanerozoic oxygen isotopic record: Geochimica et Cosmochimica Acta, v. 54, p. 1501-1509.
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