Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


MDziekanThesis_Embedded.pdf (11.56 MB)

ETD Abstract Container

Abstract Header

Origins of Basal Sediment within Kettle Lakes in Southern Michigan and Northern Indiana

Dziekan, Mitchell Ryan
http://rave.ohiolink.edu/etdc/view?acc_num=toledo151134782359727

Abstract Details

2017, Master of Science, University of Toledo, Geology.
Finding datable material to constrain ages of deglaciation is a key challenge faced by many Quaternary geologists. Often kettle lakes contain datable material in the form of wood and other terrestrial macrofossils within their basal sediment. These sediment units are frequently sandy layers interpreted as being deposited during downwasting as ice blocks melt within a growing kettle basin. This melting process takes time, resulting in a lag between deglaciation and the radiocarbon ages obtained from these units. Though extensively used in dating deglacial events associated with the retreat of the Laurentide Ice Sheet, little effort has been made to study this lag time and quantify its duration. This study’s main objective was to characterize the depositional environment of these “basal trash layers” and determine the extent of melt-out time lags in the region previously covered by the Saginaw Lobe of the Laurentide Ice Sheet. Six lakes along the Shipshewana and Sturgis moraines in northern Indiana and southern Michigan were cored and two separate lithofacies were consistently recovered: a lower pebbly sand with variable organic content, and an upper lacustrine mud. The lower pebbly sand does not exhibit the depositional characteristics frequently described for basal trash layers. Instead, the stratigraphic, geochemical, and physical characteristics of this lower facies suggest deposition by glaciofluvial, fluvial, and/or littoral processes. Radiocarbon and optically stimulated luminescence chronology from these cores largely does not constrain the extent of melt-out time lags within these basins, aside from two lakes, where melt-out time lags of 5 ka and 7 ka are documented based on differences between basal OSL and radiocarbon ages. These OSL ages provided potential minimum ages for the Sturgis and Shipshewana moraines of 20.4 ± 1.4 ka and 23.6 ± 1.1 ka respectively, and may also provide evidence of an earlier retreat of the Saginaw Lobe than previously inferred. Furthermore, basal radiocarbon sampling from these lakes continuously provided ages of ~16.0 cal ka BP. This consistency may mark a regional climate signal, indicative of warming in this region of North America, potentially related to Heinrich Event 1 and the climate conditions of the mystery interval between 17.5-14.9 ka.
Timothy Fisher (Committee Chair)
James Martin-Hayden (Committee Member)
Henry Loope (Committee Member)
B. Brandon Curry (Committee Member)
145 p.
Geology; Geomorphology
Quaternary Geology, Laurentide Ice Sheet, Saginaw Lobe, Sturgis Moraine, kettle lakes, radiocarbon, OSL, Michigan, Indiana, time lags, melt-out, trash layers

Recommended Citations

Citations

  • Dziekan, M. R. (2017). Origins of Basal Sediment within Kettle Lakes in Southern Michigan and Northern Indiana [Master's thesis, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo151134782359727

    APA Style (7th edition)

  • Dziekan, Mitchell. Origins of Basal Sediment within Kettle Lakes in Southern Michigan and Northern Indiana. 2017. University of Toledo, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo151134782359727.

    MLA Style (8th edition)

  • Dziekan, Mitchell. "Origins of Basal Sediment within Kettle Lakes in Southern Michigan and Northern Indiana." Master's thesis, University of Toledo, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=toledo151134782359727

    Chicago Manual of Style (17th edition)

toledo151134782359727
422
© 2017, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.