Browsing by Subject "till"

Now showing 1 - 3 of 3
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    OFR09-02, Minnesota Soil, Till, and Ground-Water Geochemical Data
    (Minnesota Geological Survey, 2009) Lively, R.S.; Thorleifson, L.Harvey
    The rocks and soils that are the foundation of our environment leave an imprint on the chemistry of our water and our lives. This chemical landscape reflects a combination of natural history and cumulative human impacts, and it influences biodiversity and human health. Geochemical mapping thus is needed to clarify elemental variations, and to support assessment of the natural and human-influenced factors that dictate these variations. The Minnesota Geological Survey (MGS) and the Minnesota Pollution Control Agency (MPCA), in cooperation with the United States Geological Survey (USGS), therefore have assembled three geochemical data sets for soil and water as a basis for an atlas that will provide an overview of geochemical patterns, and a reference that will place more thorough environmental geochemical surveys into a context. Data contributed to the project were derived from soil, soil parent material, and well water samples analyzed following USGS, Geological Survey of Canada, and Environmental Protection Agency protocols, respectively. The soil data include stream sediments largely in the western part of the state, and the soil parent material data are from sites underlain by till. The well water samples were from multiple aquifers utilized for drinking water, at greatly varying depth and geology.
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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.
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    Upper Midwest Tillage Guide
    (2021) DeJong-Hughes, Jodi; Daigh, Aaron
    A comprehensive guide to tillage in the Upper Midwest. Includes: - A brief history of soil tillage and tillage research - Tillage implements, purpose, and ideal use - Reducing tillage intensity - Economics of tillage