Title

Great Lakes paleohydrology: Complex interplay of glacial meltwater, lake levels, and sill depths

Abstract

The oxygen isotope record of ostracode and clam shells recovered from Great Lakes cores of known age allows definition of times when meltwaters from the Laurentide ice sheet were important components of lake water in the several lake basins since 12 ka. We find that the lowstands in Lake Huron and Georgian Bay are characterized by isotopically light waters (δ18O values of -20‰ to -22‰ relative to SMOW [standard mean ocean water]) and the highstands by isotopically heavy waters of more local origin. These data can be used to determine the degree of hydraulic separation among the early Holocene lakes. Southern Lake Michigan, for instance, may mix with northern-source waters only during times of rising and high water levels. Generally it is characterized by waters of local origin.

Publication Date

12-1994

Journal Title

Geology

Publisher

Geological Society of America

Digital Object Identifier (DOI)

10.1130/0091-7613(1994)​022<1059:GLPCIO>​2.3.CO;2

Document Type

Article