|
|
|
|
|
Thomas
Algeo Specializations Fieldtrips / Workshops (recent) |
GEOL 103: Historical Geology GEOL 104: Geology of the Human Environment: National Parks GEOL 107: Field Geology of Cincinnati GEOL 399: Global Climate Change (Honors) GEOL 502: Sedimentary Petrology GEOL 531: Sedimentation & Stratigraphy GEOL 604: Carbonate Depositional Environments GEOL 611: Stable Isotope Geochemistry GEOL 488/881: Sedimentology Seminar |
My research program entails study of the stratigraphy
and geochemistry of marine carbonates and black shales with an emphasis
on analysis of global systems and events. Specific research projects include: Paleoceanography of the Late Pennsylvanian Midcontinent Sea (LPMS)—The LPMS of North America reached its greatest extent during glacioeustatic highstands from the Middle Pennsylvanian to the Early Permian. At these times, the sea was strongly stratified, with a subpycnoclinal layer that was anoxic and intermittently sulfidic despite low rates of marine primary productivity. I am investigating factors controlling benthic redox conditions and other paleoceanographic variables through chemostratigraphic analysis of Midcontinent cyclothems and comparative analysis of modern epicratonic seas. Devonian Global Events and Land-Plant Evolution—The Middle to Late Devonian witnessed a major biotic crisis over a ~20 million year interval, widespread marine anoxia and black shale deposition, and large anomalies in the geochemical cycles of C, P, and S. I have proposed a new theory linking these events to the coeval evolution of vascular land plants and to rapid terrestrialization of continents via a transient increase in rates of pedogenesis (soil formation) and chemical weathering associated with the spread of land plants. I am currently undertaking studies of organic fluxes and weathering rate proxies (such as seawater Os isotopes) on black shales of Middle and Late Devonian age to test aspects of this theory. Publications (Selected) Algeo, T.J., and Ingall, E.D., 2007, Sedimentary Corg:P ratios, paleocean ventilation, and Phanerozoic atmospheric pO2: Palaeogeography Palaeoclimatology Palaeoecology, in press. Algeo, T.J., Lyons, T.W., Blakey, R.C., and Over, D.J., 2007, Hydrographic conditions of the Devono-Carboniferous North American Seaway inferred from sedimentary Mo-TOC relationships: Palaeogeography Palaeoclimatology Palaeoecology, in press. Turgeon, S., Creaser, R., and Algeo, T.J., 2007. Re-Os depositional ages
and seawater Os estimates for the Frasnian-Fammenian Boundary. Earth
and Planetary Science Letters, v. 261, p. 649-661. Algeo, T.J., Ellwood, B.B., Nguyen,T.K.T., Rowe, H., and Maynard, J.B., 2007, The Permian-Triassic boundary at Nhi Tao, Vietnam: Evidence for recurrent influx of sulfidic watermasses to a shallow-marine carbonate platform: Palaeogeography Palaeoclimatology Palaeoecology, v. 252, p. 304-327, doi:10.1016/j.palaeo.2006.11.055. Algeo, T.J., Heckel, P.H., Maynard, J.B., Blakey, R., and Rowe, H., 2007. Modern and ancient epicratonic seas and the superestuarine circulation model of marine anoxia. In: Holmden, C., Pratt, B.R. (Eds.), Dynamics of Epeiric Seas: Sedimentological, Paleontological and Geochemical Perspectives. Geological Association of Canada Special Publication, in press. Tribovillard, N., Algeo, T.J., Lyons, T.W., and Riboulleau, A., 2006, Application of trace metals as paleoredox and paleoproductivity proxies: Chemical Geology, v. 232, p. 12-32. Algeo, T.J., and Lyons, T.W., 2006, Mo–total organic carbon covariation in modern anoxic marine environments: Implications for analysis of paleoredox and paleohydrographic conditions, Paleoceanography, 21, PA1016, doi:10.1029/2004PA001112. Algeo, T.J., 2004, Can marine anoxic events draw down the trace-element inventory of seawater? Geology, v. 32, p. 1057-1060. Algeo, T.J., and Maynard, J.B., 2004, Trace element behavior and redox facies in core shales of Upper Pennsylvanian Kansas-type cyclothems. Chemical Geology, v. 206, p. 289-318. |
Department
of Geology Box
210013 ttel:
513-556-3732 fax: 513-556-6931 |