Browsing by Subject "geochemistry"

Now showing 1 - 11 of 11
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    Carbon Dioxide Sequestration in Sedimentary Reservoirs: Fundamental and Applied Considerations
    (2015-05) Tutolo, Benjamin
    Greenhouse gas emissions and their associated changes to Earth’s climate, hydrologic, and ecological systems are amongst the most pressing issues facing society in the twenty-first century. In this thesis, I explore fundamental and applied aspects of one of the proposed methods for transitioning from a fossil fuel-burning, greenhouse gas emitting society to a renewable energy-based society: Carbon Capture, Utilization, and Storage (CCUS). CCUS involves capturing carbon dioxide (CO2 ) from point sources, such as coal-fired power plants, injecting it deep underground into permeable, porous geologic formations, and, potentially, utilizing the injected CO2 to extract geothermal energy from the subsurface. CCUS is an inherently multi-faceted problem, with researchers and practioners ranging in fields from the Earth sciences to engineering, economics, and public policy, amongst other fields. Within the Earth sciences alone, researchers must focus on a variety of processes, including (but not limited to): the thermodynamics and kinetics of geochemical reactions; the flow and transport of CO2 , reservoir brines, dissolved solutes, and heat; and the evolution of porosity and permeability with the progression of geochemical reactions and mechanical stresses. Here, my co-authors and I offer perspectives and advancements within these sub-fields of the Earth sciences. Specifically, Chapters 2 and 3 focus on the thermodynamics of relevant chemical reactions; Chapters 4 and 5 focus on experimental observations of coupled fluid flow, chemical reactions, and porosity/permeability changes; and Chapter 6 focuses on placing laboratory-scale observations of these coupled processes into the reservoir scale. Together, these chapters offer a glimpse of the immensely multi-faceted nature of CCUS research.
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    Ecology And Chemistry Of Small Mammals And The Implications For Understanding Their Paleoecology And Environments
    (2015-07) Haveles, Andrew
    Fundamental goals of paleoecologists and modern ecologists is to understand the evolutionary and ecological patterns in modern and ancient biodiversity. Diet is one ecological trait species may evolve or vary to exploit food resources and increase their fitness. Stable isotope analysis is one method used to infer diet and is transferable between modern and fossil populations. Stable isotope analysis has not been commonly applied to small mammals, mostly because of sampling limitations. Here, three studies focus on furthering our understanding of small mammal ecology and serve as a baseline comparison for interpreting similar data from the fossil record. Chapter 1 illustrates that small mammals varied their diets independently and indicate granivores focused on C4 derived resources, generalists consumed resources readily available, and an invertivore focused on invertebrates. Results indicate that intermediate ?13C values between C3 and C4 resources are likely from integrating multiple resources through direct consumption and invertivory. Therefore, interpreting ?13C values from consumers in the fossil record must be interpreted with caution. Chapters 2 and 3 include a ?13C dataset that expands to the regional scale and assess how rodent partition C3 and C4 resources as C4 biomass on the landscape varies. Small mammals mostly rely on C3 derived resources, but there are some spatial and ecological tendencies with granivores incorporating the most C4 derived resources and varied with C4 biomass. Climate variables explained some variance in C4 consumption for some species, while other species' diets were not explained by climate. Seasonality metrics were the best predictors of C4 consumption and ?13C values in rodent hairs were more positive during peak C4 growing seasons. Chapter 4 estimates temperature and precipitation using the area extant species' geographic ranges overlap today and then applied to ancient faunas where the same species co-occur. Temperature and precipitation estimates for Pleistocene-Holocene localities reflect the general warming during this transition and interpolated temperature and precipitation for climate intervals illustrate deviating spatial gradients through time. The culmination of work presented here greatly improves our understanding of small mammal ecology and sets s baseline for testing modes of evolution and ecology in the fossil record.
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    Geology, geochemistry, and PGE potential of mafic-ultramafic intrusions in Minnesota, excluding the Duluth Complex
    (Minnesota Geological Survey, 2006) Jirsa, M.A.; Miller, James D., Jr.; Severson, M.J.
    This open-file contains data from both the first and the second phase of a 3-year study to evaluate platinum group element potential in mafic-ultramafic intrusions throughout Minnesota, excluding the Duluth Complex. Specifically, it reports the results of geochemical analyses conducted on 20 intrusions selected from more than 150 that were inventoried during the first phase of the study released in 2003. Some overlap may occur between the geochemical data listings from Phase 1 and Phase 2.
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    Guidebook 5. Field Trip Guide Book for Precambrian Migmatitic Terrane of the Minnesota River Valley
    (Minnesota Geological Survey, 1972) Grant, J.A.; Himmelberg, Glen R.; Goldich, S.S.
    The Minnesota River Valley provides a tantalizing window onto the Canadian Shield on the eastern margin of the Great Plains, tantalizing because of the high grade of the metamorphism, and especially because of the antiquity of the rocks there exposed. Essentially, this is a migmatitic terrane of granitic gneisses with lesser amphibolitic gneisses, commonly with pyroxene, and biotite-rich gneisses, which may contain garnet, cordierite, sillimanite, anthophyllite, or hypersthene. Some of the rocks are greater than 3.0 b.y. in age, and they have been involved in metamorphism and deformation at least 2.6 b.y. ago. These events left rocks with a metamorphic grade in the upper amphibolite or granulite facies, and with a major structure that is similar throughout most of the exposed area. Later minor intrusions, dominantly mafic, cut the older rocks, and conglomerate and quartzite of the Sioux Formation of Late Precambrian age locally overlie them. Deep weathering of the gneisses formed a regolith about 100 feet thick, a part of which was reworked in the formation of Cretaceous deposits of sand and clay. Over this came the glacial deposits of the Pleistocene. With the formation of Lake Agassiz, drainage via Glacial River Warren scoured out the precursor of the present valley leaving an underfit present-day Minnesota River and the glimpse of the Precambrian described in the following pages. The granitic gneisses in the vicinities of Morton, Granite Falls, and Montevideo are among the oldest known crustal rocks. Like very ancient rocks in other parts of the world the gneisses have had a complicated history, and metamorphic changes have masked their original characters and obscured their age. Conservatively the age may be given as 3200 or 3300 m. y. Goldich and others (1970) have attempted to probe the metamorphic history and concluded that the gneisses date back to 3550 m.y. ago. Similarly old, or older gneisses (3600 to 4000 m.y.) have been reported from the Godthaab district, West Greenland (Black and others, 1971). Field and more detailed geochronological and geochemical investigations are being continued, and the nature of this work is briefly indicated in following sections.
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    Hot spring water, biofilm, and contextual samples from Yellowstone National Park collected under Permit YELL-2022-SCI-7020 by Havig and Hamilton for publication support of submitted manuscript on nitrogen isotope and nifH data.
    (2024-09-19) Havig, Jeff R.; Hamilton, Trinity L.; jhavig@umn.edu; Havig, Jeff R.; MAD EGG LAB and The Fringe Lab, Dept. of Plant and Microbial Biology, UMN
    This data has been generated by Dr. Jeff R. Havig and Dr. Trinity L. Hamilton, Dept. of Plant and Microbial Biology, University of Minnesota. The data compiled in this spreadsheet represents water geochemistry and biofilm molecular data collected under Yellowstone Permit YELL-2022-SCI-7020, used for submitted publication "Between a Rock and a Soft Place: Biomass δ15N Values of Hot Spring Microbial Communities and Their Potential for Preservation in the Rock Record", submitted March, 2024 to JRG Biogeosciences by Havig and Hamilton. Any publications that use this data are requested to cite the final accepted paper.
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    Information Circular 44. Geochemical Evaluation of Platinum Group Element (PGE) Mineralization in the Sonju Lake Intrusion, Finland, Minnesota
    (Minnesota Geological Survey, 1999) Miller, James D., Jr.
    This study was undertaken to evaluate the potential for stratiform platinum group element (PGE) mineralization in the Sonju Lake intrusion (SLI). The SLI is a well differentiated, tholeiitic, mafic layered intrusion that is part of the multiple intrusive Beaver Bay Complex, and is exposed near Finland, Minnesota. Geochemical analyses of outcrop and drill-core samples that span the 1200-m-thick SLI were interpreted in the context of (1) data from PGE reefs in other tholeiitic layered intrusions (most notably the Skaergaard intrusion of East Greenland), and (2) models of PGE and sulfide mineralization in tholeiitic intrusions. The geochemical data show that a PGE-mineralized horizon is present approximately two-thirds of the way up from the base of the moderately south-dipping, sheet-like SLI. PGE mineralization was apparently related to initial sulfide saturation and subsequent exsolution of sulfide melt from the SLI magma. The data also indicate that as it settled, the sulfide melt efficiently scavenged PGEs from the SLI magma, and concentrated them into a relatively narrow interval of gabbroic cumulates. The geochemical signature of the SLI is remarkably similar to that of the PGE-bearing Platinova reef in the Skaergaard intrusion. The highest Pd, Pt and Au concentrations in SLI outcrop samples are far from economic grade (360, 66, and 85 ppb respectively); but a more precise evaluation of peak grade, thickness, and lateral continuity requires drilling and analysis of the entire interval. When the results of the study reported here are combined with evidence for similar mineralization in the Layered Series at Duluth, they indicate that tholeiitic layered intrusions of the Duluth and Beaver Bay complexes are favorable exploration targets for reef-type PGE mineralization.
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    Information Circular 45. Utility of Elemental Geochemical Data in Correlation and provenance Studies of Pleistocene Materials: A Case Study in Stearns county, Central Minnesota
    (Minnesota Geological Survey, 2000) Morey, G.B.; Lively, R.S.; Meyer, Gary N.
    Geochemical attributes, especially minor, trace, and rare-earth elements, are commonly used to characterize various kinds of sedimentary rocks and to elucidate their provenance. Similar techniques have been applied to glacial materials with varying degrees of success. In Minnesota, for example, Martin and others (1989, 1991) concluded that few if any geochemical elements were useful for correlating tills across large areas. In contrast, Gowan (1998), in a study of six till units from central Minnesota, concluded that geochemical attributes were useful in delineating stratigraphic units and their provenance. Results of a similar study in southwestern Minnesota (Patterson and others, 1995) were inconclusive. The geochemical studies undertaken to date in Minnesota have utilized the silt and clay-size fraction as a sample medium and Atomic Adsorption spectrometry or Inductively Coupled Plasma emission spectrometry as the principal analytical technique. Unfortunately, both techniques require that the sample medium be dissolved prior to analysis, which can limit the value of the resulting data. For example, relative to the composition of the sample matrix and the particulates, certain minerals and elements may be selectively leached or incompletely dissolved, or spectral signals from some concentrated elements may interfere with weaker signals from less abundant elements. Such problems are best addressed by the use of replicates and standards developed from materials similar to those being analyzed. To our knowledge, sets of material standards that could be used to calibrate the various analytical methods have not been developed for Pleistocene sediments in Minnesota. In this study we avoided problems associated with partial dissolution and interference by using Instrumental Neutron Activation Analysis (INAA) techniques (XRAL Activation Services Inc., Ann Arbor, Michigan). We analyzed 123 subsurface samples from five drill sites in Stearns County, east-central Minnesota, for 32 elements. The results in this report are not directly comparable with those of Martin and others (1988), Gowan (1998), and Patterson and others (1995), because they were obtained on whole-rock samples from which only clasts of pebble or larger size had been removed. Nonetheless, the data provide insight into the utility of geochemical techniques to investigate provenance and transport patterns of glacial materials. The complete file of analytical data is summarized in the Appendix.
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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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    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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    Seyfried Lab Data: Geochemical Analyses of Lost City Vent Fluids (collected 2008; analyzed 2022) and experimental fluids from lherzolite alteration experiments (2022)
    (2024-06-27) Evans, Guy N; gevans@umn.edu; Evans, Guy; University of Minnesota Aqueous Geochemistry Lab
    This data set contains chemical analyses of vent fluids collected from Lost City Hydrothermal Field (LCHF) using isobaric gat tight samples in 2008 (cruise KNOX18RR). Analyses of acidified archived samples stored at University of Minnesota were conducted in 2022 with a focus on nutrient transition metal concentrations. An analysis of contemporaneous seawater local to LCHF is also included. This data set also includes chemical analyses of experimental fluid samples obtained from a hydrothermal lherzolite alteration experiment performed at the University of Minnesota in Spring, 2022. 45 g spinel lherzolite from Damaping, Hebei, China (LDMP) was reacted with aqueous solution containing Na = 410 mmol/kg, Ca = 45 mmol/kg, Cl = 500 mmol/kg at 300 degrees C, 500 bar an initial water:rock mass ratio of 1:1.