Date of Award


Document Type


Degree Name

Bachelor of Science (BS)




An optical study of the heavy minerals of the till in two lithostratigraphic units in Polk, Red Lake, and Norman Counties in northwestern Minnesota was undertaken. The purpose was to determine whether the assemblages are different enough to differentiate the two tills and whet her the assemblages are laterally consistent enough to be used as a basis for correlation.

An earlier study (Hobbs, 1973) showed that these tills outcropping in the Red Lake Falls area could be distinguished on the basis of heavy-mineral analysis.

Both units contain hornblende, pyroxene, garnet, magnetite, and epidote, but in different proportions. The upper unit, the Huot Formation, has significantly more epidote and amphibole and less garnet and pyroxene than the Red Lake Falls Formation. It was found that these differences are laterally too variable to be used as a direct basis for correlation.