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E. Troy Rasbury

Associate Professor
Office: ESS 320
Phone: 631-632-1488

Website: Troy Rasbury

B.S., Midwestern State University, 1984 
M.S., Tulane University, 1990 
Ph.D., SUNY Stony Brook, 1998 
Assistant Professor at Queens College 1998-1999 
Faculty member at Stony Brook starting Fall 1999

 I use isotopes and trace elements to address questions of age, provenance, and process. One of the most fundamental problems in geology is time resolution. My career long focus has been in exploring the potential for U-Pb dating of sedimentary carbonates for the purpose of improving time resolution in the sedimentary rock record. This work is summarized in a recently published review paper by Rasbury and Cole (2009).

My interest in dating sedimentary carbonates has driven me to consider the behavior of U in sedimentary environments in general. Work at the National Synchrotron Light Source lead to the surprising discovery of oxidized U in a calcite sample with multiple lines of evidence for reducing conditions at the time of its formation (McCall et al., 2001; Kelly et al., 2006). The clear association of U with organic matter prompted us to ask if U might be in the oxidized state other widely recognized U- NOM (natural organic matter) associations. Cores of peat from a Holocene wetlands system in eastern Washington show that U primarily occurs in the oxidized state in this fen system (this confirms work of Zielinski and others who used other techniques to indirectly deduce that U was oxidized). Perhaps even more surprising, the zone of reduced U contains the lowest U concentrations in the approximately 1.5 meter profile. 
In addition to careful petrographic study, I approach sample selection for U-Pb dating from several directions including 1) a focus on the controls on U speciation in depositional environments and how this controls its incorporation into carbonates (Kelly et al., 2007), 2) trace element mapping at beamline X26A at the NSLS 3) fission track maps, and 4) autoradiography (Cole et al., 2003).

Selected Publications 

Rasbury, E. T., and Cole, J., M., 2009, Direct Dating of Geologic Events: U-Pb Dating of Carbonates: Reviews of Geophysics, v. 47, RG3001, doi: 10.1029/2007RG000246.

Druschke, P., Hanson, A. D., Wells, M. L., Rasbury E. T., and Stockli, D. F., 2009, Synconvergent surface-breaking normal faults of Late Cretaceous age within the Sevier hinterland, east-central Nevada: Geology, v., p. 447-450

Folk, R. L., and Rasbury, E. T., 2007, Nanostructure of palygorskite/sepiolite in Texas calcihe: Possible bacterial origin: Carbonates and Evaporites, v. 22, p. 113-122.

Rasbury, E. T., Gierlowski-Kordesch, E. H., Cole+, J. M., Sookdeo*, C., Spataro*, G., Nienstedt*, J., 2006, Calcite Cement Stratigraphy of a Non-Pedogenic Calcrete in the Triassic New Haven Arkose (Newark Supergroup): Geological Society of America Spec. Pub 416: Paleoenvironmental Record and Applications of Calcretes and Palustrine Carbonates. p. 203-221.

Kelly, S. D., Rasbury E. T., Chattopadhyay, S., Kropf, A. J., Kemner, K. M., 2006, Evidence of a Stable Uranyl Site in Ancient Organic-Rich Calcite:Environmental Science &Technology,  40,  2262-2268.

Cole+, J. M., Rasbury, E. T., Hanson, G. N., Montañez, I. P., Pedone, V. A., 2005, Using U-Pb ages of Miocene tufa for correlation in a terrestrial succession, Barstow Formation, California: Geological Society of America Bulletin, 117, 276-287.

Rasbury, E. T., Ward, W. B., Hemming, N. G., Li+, H., Dickson, J. A. D., Hanson, G. N., Major, R. P., 2004, Concurrent U-Pb age and seawater 87Sr/86Sr value of marine cement: Earth and Planetary Science Letters, 221, 355-371.

Cole+, J. M., Rasbury, E. T., Montañez, I. P., Pedone, V. A., Lanzirotti, A., Hanson, G. N., 2004, Petrographic and trace element analysis of uranium-rich tufa calcite, middle Miocene Barstow Formation, California: Sedimentology, 51, 433-453.

Becker+, M. L., Rasbury, E. T., Meyers, W. J., Hanson, G. N., 2004, U-Pb calcite age of the Late Permian Castile Formation, Delaware Basin: constraint on the age of the Permian-Triassic Boundary? Reply to a comment by Ian Metcalfe: Earth and Planetary Science Letters, 217, 469-471.

Cole+, J. M., Nienstedt*, J., Spataro*, G., Rasbury, E. T., Lanzirotti, A., Celestian, A. J., Nilsson, M., Hanson, G. N., 2003, A method for determining relative uranium concentrations in geological samples on a hand specimen scale: Chemical Geology, 193, 127-136.

Folk, R. L. and Rasbury, E. T., 2002, Nanometer-scale spheroids on sands, Vulcano, Sicily: possible nannobacterial alteration: Terra Nova, 14, 467-475.

Becker+, M. L., Rasbury, E. T., Meyers, W. J., Hanson, G. N., 2002, U-Pb calcite age of the Late Permian Castile Formation, Delaware Basin: constraint on the age of the Permian-Triassic Boundary?: Earth and Planetary Science Letters, 203, 681-689.

Becker+, M. L., Cole+, J. M., Rasbury, E. T., Pedone, V. A., Montañez , I. P., Hanson, G. N., 2001, Cyclic variations of uranium incorporation in tufa from the Miocene Barstow Formation, Rainbow Basin, Mojave, California: Geology, 29, 139-142.

Rasbury, E. T., Meyers, W. J., Hanson, G. N., Goldstein, R. H., Saller, A. H., 2000, Relationship of uranium to petrography of caliche paleosols with application to precisely dating the time of sedimentation: Journal of Sedimentary Research, 70, 604-618.

Hemming, S. R. and Rasbury, E. T., 2000, Pb isotope measurements of sanidine monitor standards: Implications for provenance analysis and tephrochronology: Chemical Geology, 165, 331-337.

Saller, A.H., Dickson, J.A.D., Rasbury, E.T., Ebato, T. 1999, Effects of long-term accommodation changes on short-term cycles, late Paleozoic platform limestones, West Texas: in Harris, Saller, and Simo, eds, SEPM Special Publication No. 63, Introduction to advances in carbonate sequence stratigraphy- application to reservoirs, outcrops and models, p. 227-246.

Rasbury, E. T., Hanson, G. N., Meyers, W. J., Holt, W. E., Goldstein, R. H., Saller, A. H., 1998, U-Pb dates of paleosols: Constraints on late Paleozoic cycle durations and boundary ages: Geology, 26, 403-406.

Wang, Z. S., Rasbury, E. T., Hanson, G. N., Meyers, W. J., 1998, Dating the time of sedimentation of clastic sedimentary rocks using U-Pb system of calcretes:Geochimica et Cosmochimica Acta, 62, 2823-2835.

Marcantonio, F., Higgins, S., Anderson, R. F., Stute, M., Schlosser, P.,  Rasbury, E. T., 1998, Terrigenous helium in deep-sea sediments: Geochimica et Cosmochimica Acta, 62, 1535-1543.

Rasbury, E. T., Hanson, G. N., Meyers, W. J., Saller, A. H., 1997, Dating of the time of sedimentation using U-Pb ages of paleosol calcite: Geochimica et Cosmochimica Acta, 61, 1525-1529.

Invited Contributions:
Rasbury, E. T. and Cole+, J. M., 2006, Directly Dating Sedimentary Rocks: 2006 Paleontological Society Shortcourse at annual GSA meeting in Philadelphia.

Rasbury, E. T., 2002, Geochronology: McGraw-Hill Yearbook of Science & Technology, p. 143-145.

McCall+, K., Lanzirotti, A., Rasbury, E. T., 2001, U (VI) Incorporation in Paleosol Calcite: Evidence for Sequestration of U on Geologic Time Scales: NSLS Activity Report 2001

Becker+, M. L., Rasbury, E. T., Hanson, G. N., Meyers, W. J., 2001, Refinement in the age of the Carboniferous-Permian boundary based on U-Pb dating of biostratigraphically constrained syn-sedimentary carbonates in the Appalachian region, North America: Carboniferous Newsletter, 19, 18-20.

Recent Abstracts:
Rasbury, E. T., and Hemming, N. G., 2009, Secular trends in d11B and prospects for determining the direction of paleo pCO2 change: Goldschmidt Conference Abstracts: Geochimica et Cosmochimica Acta, v. 73, p. A1073.

Penman, D., Rasbury E. T., Hemming, N. G., Hönisch, B., Abejar, P., and Butts, S., 2008, Heavy boron isotopic composition of Pennsylvanian brachiopod calcite: Implications for pH, CO2 and secular variation of seawater d11B: Eos Trans. AGU, 89(53), Fall Meet. Suppl., Abstract PP41D-1477.

Rasbury, E. T., Holt, W. E., Frodsham, A+., Ekstrom, B. and Wilson, J., 2008, The relationship between 87Sr/86Sr and seawater chemistry: GSA national meeting, Houston, Texas.

Rasbury, E. T., Northrup, P. A., and Hemming, N. G., 2008, Importance of natural organic matter in U sequestration revealed by the study of a natural wetlands system in eastern Washington state: ACS National Meeting, Philadelphia, Pennsylvania.

Rasbury, T., Hemming, G., Dickson, T., Barrick, J. and Saller, A., 2008, Dates, Rates and Global Correlation of the Permian of West Texas Based from Coupled U-Pb Carbonate Ages and Sr Chemostratigraphy: AAPG National Meeting San Antonio Texas.

Rasbury, T., Ward, W. B., Hemming, N. G., Montanez, I. P., and Grammer, G. M., 2008, Dated Marine Carbonates Aid in Reconstructions of Deep- Time Climate Change: AAPG National Meeting San Antonio Texas.

Rasbury, E. T., 2007, Where is the U in Calcite?: Eos Transactions, AGU, H34A-05 INVITED

Rasbury, E. T., 2007, Linking the end of glaciation in Gondwana to aridity in the tropics: Coupled Sr chemostratigraphy and cyclostratigraphy from the Permian Basin, Texas, Eos Transactions, AGU, H33E-07.

Cole, J. M., Rasbury, E. T., Hemming, S. R., Machlus, M., and Swisher, C. C., 2007, 40Ar39Ar dating of the middle Miocene Skyline Tuff, Barstow Formation, CA: Eos Transactions, AGU, H34A-06.

Copeland, P., Watson, E. B., Canino, M., Cox, K., and Rasbury, T., 2007 Alpha termochronology of calcite: Goldschmidt Conference Abstracts, Cologne, Germany, A187.

Hendy, E. J., Lanzirotti, A., Rasbury, T., and Lough, J., 2007, Trace element distributions and coral skeleton micromorphology following a bleaching event: Goldschmidt Conference Abstracts, Cologne, Germany, A395. 

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