Browsing by Author "Thorleifson, L.H."

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    OFR16-01, Quaternary stratigraphy of Minnesota: statewide cross-sections, Minnesota Geological Survey
    (Minnesota Geological Survey, 2016) Lusardi, B.A.; Gowan, A.S.; Meyer, G.N.; Thorleifson, L.H.
    Seven cross sections were constructed as part of our comprehensive plan to formally define and map Quaternary lithostratigraphic units across Minnesota.
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    OFR19-02, Geochemical Analysis of Till From Minnesota Drill Cores
    (Minnesota Geological Survey, 2019) Thorleifson, L.H.; Conrad, D.R.; Staley, A.E.
    Compositional analysis of texture and very coarse sand lithology have been used to support characterization of till properties, and interpretation of correlation, process, and provenance. In 2007, results were released for more thorough compositional analyses of near-surface till samples collected statewide. Quaternary stratigraphic efforts are now focused on information needed to support regional groundwater management. To support that effort, till from selected rotasonic cores extending to tens of meters depth were submitted in 2018 and 2019 for geochemical analysis following the method used for part of the 2007 study - four-acid leach of air dry <63 micron fraction followed by ICP. Examples of elements that correlated to provenance are As in shale-rich till, Ca in carbonate-rich till, Na in shield-derived till, and Fe in Lake Superior-derived till. All data are here provided as a reference.