Browsing by Author "Thorleifson, L.Harvey"

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    OFR 07-01, Till geochemical and indicator mineral reconnaissance of Minnesota
    (Minnesota Geological Survey, 2007) Thorleifson, L.Harvey; Harris, K.L.; Hobbs, H.C.; Jennings, C.E.; Knaeble, A.R.; Lively, R.S.; Lusardi, B.A.; Meyer, G.N.
    As a cooperative project of the Minnesota Geological Survey and industry, the entire State of Minnesota and adjacent regions was sampled for till geochemistry and indicator minerals at a 30-km spacing during summer 2004. Within target cells, each a quarter-degree latitude by a half-degree longitude, till from between about 1 and 2 m depth was sampled by filling a 15 liter plastic pail. At a few sites, vertical profiles were collected. In addition, three transects to the north were sampled, to help identify sediments derived by long-distance glacial transport, to obtain reference samples from the Thompson nickel belt, and also to extend sampling to the limit of Hudson Bay-derived carbonate-bearing sediments, to permit comparison to Minnesota carbonate-bearing sediments. Three control samples anomalous in kimberlite indicator minerals from Kirkland Lake, Ontario, were also obtained. The resulting batch consisted of 250 samples covering Minnesota and adjacent areas, 20 samples from Canada, and the three standards. The results are a highly significant step forward in mapping our geochemical landscape, in clarifying mineral potential, in provision of reference data useful to environmental protection, public health, and exploration, and in supporting follow-up with respect to potential mineralization.
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    OFR 07-04, Three-Dimensional Geologic Mapping for Groundwater Applications: Workshop extended abstracts, Denver, Colorado, Annual Meeting Geological Society of America
    (University of Minnesota, 2007) Thorleifson, L.Harvey; Berg, Richard C.; Russell, Hazen
    This fifth workshop, discussing three-dimensional (3D) geological mapping for groundwater applications, is part of an ongoing series that began in 2001. A focus of all the workshops has been the development of techniques to optimize internal consistency and to fully integrate 3-D stratigraphic with hydrostratigraphic models that can be used directly for hydrogeologic modeling. Workshops have emphasized the need for high-quality data, the procedures for reconciling often disparate and plentiful archival data, and the obvious realization that the better the geological model, the greater the probability that subsequently derived groundwater flow models will be as accurate as possible.
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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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    OFR11-02, Potential for Implementation of Mineral Carbonation as a Carbon Sequestration Method in Minnesota
    (Minnesota Geological Survey, 2011) Thorleifson, L.Harvey
    Minnesota, with a population of about five million, is a significant source of greenhouse gas emissions, and a state that is vulnerable to climate change, such as the impact that increased frequency or severity of drought or storms would have on agriculture, water supply, wildlife, lake levels, and public security. Minnesota therefore has an interest in reducing our own vulnerability, while concurrently contributing to needed world-wide solutions. As has been stressed, for example, in documents prepared for and by the Minnesota Climate Change Advisory Group, emissions reductions can have multiple benefits, including conservation, cost efficiency, and air quality enhancement, while also directly contributing to mitigation of climate change. Anthropogenic climate change seems already to have begun, however, so adaptation to climate change accompanies mitigation in the climate change policy agenda. Mitigation of greenhouse gas emissions can be achieved through reduced fossil fuel combustion, while concurrently capturing and storing carbon in biomass, or in geologic repositories. It has become apparent that the best approach is likely to be for several options to concurrently be implemented. Minnesota may be well positioned to utilize the mineral carbonation method of geologic carbon sequestration, given the presence of vast tonnages of appropriate rock material in the Duluth region, some of which could be mined for copper, nickel, and platinum group elements, pending the outcome of current permitting procedures. Should these deposits go into production, a slurry of minerals suitable for mineral carbonation of CO2 would be produced as a waste product from the mines. The principal constraint to mineral carbonation at present appears to be cost. Nevertheless, there could be developments in the method, and there could be circumstances in which a particularly favorable mineral carbonation opportunity could coincide with constraints to other aspects of the sequestration procedure, such as considerations regarding transportation, thus possibly making mineral carbonation a conceivable option.