RESEARCH  

Thomas J. Algeo

Professor of Geology

University of Cincinnati

 

Paleoceanography of Epeiric Seas

I am interested in reconstructing the physical and chemical conditions that existed in ancient epeiric seas.  The practical application of this work is in an improved understanding of controls on the accumulation of organic-rich sediments that serve as hydrocarbon source rocks.   I use an integrated investigative approach that includes analysis of:

  • major and trace elements

  • TOC-TIC

  • Corg-N-S isotopes

  • Mo-U isotopes

  • biomarkers

  • petrographic data

  • time series analysis

 

 

(Figure at right from Algeo and Maynard, 2008)

 

 My most comprehensive analysis to date is of the Late Pennsylvanian Midcontinent Sea (LPMS) of North America (right).  This paleosea was interesting owing to widespread development of anoxic facies despite absence of a bounding sill, relatively shallow water depths, and modest levels of primary productivity.  The key factor controlling benthic redox conditions appears to have been lateral advection of “preconditioned” intermediate waters from Panthalassa.  As in the modern eastern tropical Pacific, the oxygen-minimum zone (OMZ) in the Late Pennsylvanian eastern tropical Panthalassic Ocean may have risen to depths of <100 m.  Lateral advection of oxygen-depleted deep waters, in combination with strong water-column stratification of the LPMS, resulted in the widespread development of anoxic conditions across the Midcontinent region during periods of glacio-eustatic highstand.  The details of LPMS paleoceanography are considered in Algeo et al. (2004), Algeo and Heckel (2008), Algeo and Maynard (2008), Algeo et al. (2008a,b), Algeo and Tribovillard (2009), and Herrmann et al. (2012).

References

Algeo, T.J., and Heckel, P.H., 2008, The Late Pennsylvanian Midcontinent Sea of North America: A review. Palaeogeography Palaeoclimatology Palaeoecology, v. 268, p. 205-221, doi:10.1016/j.palaeo.2008.03.049.

Algeo, T.J., and Maynard, J.B., 2008, Trace metal covariation as a guide to water-mass conditions in ancient anoxic marine environments. Geosphere. v. 4; no. 5; p. 872-887; doi: 10.1130/GES00174.1.

Algeo, T.J., and Tribovillard, N. 2009. Environmental analysis of paleoceanographic systems based on molybdenum-uranium covariation. Chemical Geology, v. 268, p. 211-225, doi:10.1016/j.chemgeo.2009.09.001.

Algeo, T.J., Heckel, P.H., Maynard, J.B., Blakey, R., and Rowe, H., 2008. 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, v. 48, p. 7-38.

Algeo, T.J., Rowe, H., Hower, J.C., Schwark, L., Hermann, A., and Heckel, P.H., 2008, Oceanic denitrification during Late Carboniferous glacial-interglacial cycles. Nature Geoscience, v. 1, p. 709-714, doi:10.1038/ngeo307.

Algeo, T.J., Schwark, L., and Hower, J.C., 2004, High-resolution geochemistry and sequence stratigraphy of the Hushpuckney Shale (Swope Formation, eastern Kansas): Implications for climato-environmental dynamics of the Late Pennsylvanian Midcontinent Seaway.  Chemical Geology, v. 206, p. 259-288. doi:10.1016/j.chemgeo.2003.12.028.

Herrmann, A., Kendall, B., Algeo, T.J., Gordon, G.W., Wasylenski, L., Anbar, A.D., 2012. Anomalous molybdenum isotope trends in Upper Pennsylvanian euxinic facies: Significance for use of d98Mo as a global marine redox proxy. Chemical Geology, in press. doi:10.1016/j.chemgeol.2012.05.013.

 

Last updated 17 Sept 2012

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