U.S. Geological Survey Open-File Report 2009-1137
Quaternary Geologic Framework of the St. Clair River between Michigan and Ontario, Canada
Figure 25. Acoustic-backscatter (processed from SWATHplus®) map for transect across the river at Marysville, MI. Red line shows the location of the Chirp sub-bottom profile shown in figure 26. S, area of low backscatter (dark), which is probably sand; Sg, moderate backscatter area, which is likely sand and gravel; Gs, high backscatter (light) area with dune bedforms (3- to 5-meter wavelengths), mostly gravel with sand; Cg, mottled area of high to low backscatter, which is most likely areas of clay till or glaciolacustrine with patches of gravel. Interpretations based on video transect obtained 500 m to the south (Krishnappan, 2009). Click on figure for full-sized image in PDF format, 6.5 MB.
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