26 Reconstructing Environmental Change from Marine, Lacustrine, and Terrestrial Sedimentary Records (Posters)

Saturday, 29 March 2025
8:30 AM - 5:30 PM
North Great Hall

RIDGE-PLAIN PROMONTORIES OF THE NORTH AMERICAN GREAT LAKES AS DEPOSITIONAL ARCHIVES OF CHANGING LITTORAL DYNAMICS

Paper number: 26-4
Program: Theme Sessions
Time: 8:30 AM – 5:30 PM

Authors

  • Christopher R. Mattheus Presenting Author
    University of Illinois at Urbana-Champaign, Champaign, IL
  • M.E. Barklage
    University of Illinois at Urbana-Champaign, Champaign, IL
  • A. Brizzee
    University of Illinois at Urbana-Champaign, Champaign, IL
  • Thomas Diggins
    Youngstown State University, Youngstown, OH
  • S. Huot
    University of Illinois at Urbana-Champaign, Champaign, IL
  • K. Pearce
    University of Illinois at Urbana-Champaign, Champaign, IL
  • L. Rosario
    University of Illinois at Urbana-Champaign, Champaign, IL
  • E. Spitzer
    University of Illinois at Urbana-Champaign, Champaign, IL

Abstract

While depositional proxy records within embayed ridge plains of the Great Lakes have helped with reconstructing late Holocene glacio-isostatic movements and regional changes in water balance, ridge-plain promontories have been overlooked as repositories of paleo-environmental information. Exposed to the high-energy wave/current conditions of the open lake environment, they undergo extensive reworking over time and tend to migrate in direction of prevailing littoral transport. The utility of two different Great Lakes ridge-plain promontories as repositories of information on littoral hydrodynamic and alongshore sediment-transport processes is herewith evaluated.

We have studied the physiography, stratigraphy, and geochronology of the late Holocene Zion Beach-ridge Plain of southwestern Lake Michigan and the Presque Isle Peninsula of southcentral Lake Erie, both of which have historically experienced erosion along the littoral updrift and accretion along the littoral downdrift. Stratigraphic assessment is based on ground-penetrating radar imagery and sediment-core information, while physiographic assessment made use of available coastal LiDAR datasets. Geochronological information includes archival C-14 age dates and results of optically stimulated luminescence (OSL) dating of targeted sand deposits.

Ridge sets, demarcated by high-relief (comparatively) erosional strandlines, compartmentalize the studied ridge-plain promontories. C-14 and OSL-based geochronological data suggest that (1) major lake-level fluctuations, beyond those of historical changes with decadal, meter-scale lake-level variances; and/or (2) changes in storm pattern (e.g., energy conditions of the littoral zone) are responsible. Shelter from alongshore hydrodynamic processes reduces these geomorphic signatures within coastal embayments. This underscores the importance of expanding reconstructive efforts to promontory systems for a more complete assessment of regional paleoclimate.

Geological Society of America Abstracts with Programs. Vol. 57, No. 3

doi: 10.1130/abs/2025NE-407436

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