Students supported by the
Precambrian Research Center

 

A primary objective of the PRC is to provide financial and advisory support to graduate and undergraduate students conducting field-based research on the Precambrian geology of the Lake Superior region. This support comes in the form of graduate research assistantships, which are limited to UMD graduate students, and research grants, which are available to undergraduate or graduate students from any school. The extent to which the PRC can provide such support will vary based on the annual level of Corporate and Individual Membership contributions.


Aubrey on OC

Graduate Research Assistantships

2013-2014 :Paul Fix,Alex Steiner, Adam Leu, Jon Dyess

2012-2013 :Aubrey Lee, Jon Dyess, Craig Caton, Adam Leu

2011-2012 : Ben Brooker, Matt Chaffee, Chris Goscinak

2010-2011 : Dan Foley

2008-2009 : Tom Johnson

2007-2008: Chris White

Research Grants

2013 Grantees

2012 Grantees

2011 Grantees

2010 Grantees

2009 Grantees

2008 Grantees

Graduate Research Assistantships

2013-2014 Academic Year

Student: Paul Fix
Status: 1st Year MS candidate
Primary Advisors: Tamara Deidrich (Barr Engineering. UMD adjunct), Jim Miller (associate professor)

Support
: Graduate research assistantship for 2013-2014 and 2014-15 academic years funded by Teck American donation ($63,000) to the PRC; includes analytical and travel expenses

Thesis Title: Characterization of Secondary Mineral Controls on Metal Mobility from Weathered Duluth Complex, Mesaba Deposit

Research Description:  The chemistry of mine-impacted water is dependent on a suite of geochemical processes that result in the release and/or attenuation of chemical constituents. For example, while interaction with air and water may initiate constituent release by dissolution/ oxidation, secondary mineral formation attenuates chemical constituents (Nordstrom, 2012). These secondary minerals have been observed to play an important role in limiting the mobility of metals (such as iron, copper, nickel, and cobalt) that are released during oxidation of sulfide minerals in mine-impacted systems (for example, Hochella et al., 2005., Jerz and Rimstidt, 2003., and Valente et al., 2013).  This study will use samples from weathered exposures of Duluth Complex outcrop as an analog for future potential rock that would be managed (and exposed to water and/or air) during mining of a Duluth Complex Cu-Ni deposit. I will characterize mineral occurrences, trace metal content, and textural relationships of these weathering products at the micro-scale. The secondary mineral characterization, along with an existing dataset on drainage chemistry from experimentally oxidized rock, will be used to refine a conceptual model for dissolved metal mobility at a potential future mine site managing Duluth Complex rock.
References:
Hochella, M.R., Kasama, T., Putnis, A., Putnis, C.V., Moore, J.N., 2005. Environmentally important, poorly
crystalline Fe/Mn hydrous oxides: Ferrihydrite and a possibly new vernadite-like mineral from the Clarks Fork River Superfund Complex. American Mineralogist, Vol. 90, 719-724.
Jerz, J.K., Rimstidt., J.D., 2003. Efflorescent iron sulfate minerals: Paragenesis, relative stability, and environmental impact. American Mineralogist Vol. 88, 1919-1932.
Nordstrom, D. K., 2012. Hydrogeochemical processes governing the origin, transport and fate of major and trace elements from mine wastes and mineralized rock to surface waters. Applied Geochemistry, 26. 1770-1791.

Student: Alex Steiner
Status: 2nd Year MS candidate
Primary Advisor: Jim Miller

Support
: Graduate research assistantship for 2013-2014 academic year funded by Twin Metals Minnesota donation ($34,260) to the PRC foundation; PRC research grant ($1000), and UMD Dept of Geological Sciences research grant ($1000)

Thesis Title: Genesis of Sulfide Mineralization within the Footwall Granite of the Maturi Cu-Ni-PGE Deposit of the South Kawishiwi Intrusion, Duluth Complex, NE Minnesota

Research Description: The Duluth Complex of northern Minnesota hosts one of the largest Cu-Ni-PGE deposits in the world.  Mineralization is generally located at or near the basal contact of troctolite intrusions and manifests as disseminated pyrrhotite-chalcopyrite-pentalandite.  Extensive mapping and drilling programs along the western margin of the Duluth Complex, particularly the Partridge River and South Kawishiwi Intrusions, uncovered sulfide mineralization located in footwall rocks composed of Archean granites of the Giants Range Batholith.  The footwall mineralization has been shown to be related to the emplacement of the South Kawishwi intrusion and several mechanisms of footwall mineralization have been proposed but remain untested.  This study’s goal is to test ideas suggested in previous works and determine which mechanism or mechanisms is responsible for the mineralization observed in the footwall.  To reach that goal several questions must be answered; is there an interaction between sulfide liquid and partially melted footwall? Were hydrothermal fluids significant for mineralization?  How does thermal metamorphism relate to footwall mineralzation?  To answer these questions this study focused on the Maturi Deposit (Twin Metals Minnesota) form which four drill cores were relogged and sampled, targeting mineralized and unmineralized suites of footwall rocks.  These two suites will be compared using transmitted and reflected-light petrography, mass-balance analyses of whole rock geochemistry, and mineral compositions determined by SEM-EDS analyses.  

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2012-2013 Academic Year

Student: Adam Leu
Status: 2nd Year MS candidate
Primary Advisor: Jim Miller

Support
: USGS EDMAP Grant ($14,670), PRC graduate research assistantship for Fall 2012 semester and Spring 2014 semester, PRC research grant ($1000), and UMD block grant ($1000)

Thesis Title: Geology and Petrology of the Wilder Lake Intrusion, Duluth Complex, NE Minnesota

Research Description: 160 square miles of wilderness in the Boundary Waters Canoe Area Wilderness (BWACW) was caught in a massive forest fire last autumn.  The nexus of the fire scorched the forest directly over the Wilder Lake intrusion (WLI).  The WLI occurs in the northwestern part of the Duluth Complex - a large, arcuate-shaped, multiple intrusive igneous complex that underlies most of northeastern Minnesota and constitutes the largest exposed plutonic component of the 1.1 Ga Midcontinent Rift.   The few studies conducted on the WLI show it to be one of the most distinctive intrusions of the layered series (Miller et al., 2002). This research aims to verify and evaluate the origin of some of its enigmatic features (N-dip, unique cumulate stratigraphy, reversed cryptic variation) by conducting detailed field mapping and sampling, petrographic study, mineral chemical analysis, and lithogeochemical analysis.  I will establish the lateral persistence of the cumulate stratigraphy along the 10 kilometer strike length of the WLI.  It is pertinent to take advantage of the enhanced exposure and improved overland access provided by the fire to fully document the extent and igneous stratigraphy of the Wilder Lake intrusion. 
References
Miller, J.D. Jr.,  Green, J.C., Severson, M.J., Chandler, V.W., Hauck, S.A., Peterson, D.E., and Wahl, T.E., 2002, Geology and mineral potential of the Duluth Complex and related rocks of northeastern Minnesota. Minnesota Geological Survey Report of Investigations 58, 207p. w/ CD-ROM

 

Student: Craig Caton
Status: EBT MS candidate
Primary Advisor: Penny Morton

Support
: Graduate research assistantship for 2012-13 academic year funded by Duluth Metals Ltd., PRC research grant ($1000), and UMD block grant ($1000)

Thesis Title: Petrogenesis and Metallogenesis of the Southern Troctolite Zone of the Bald Eagle IntrusionDuluth Complex, Northeastern MN

Research Description: The overall goal of this project is to understand the petrogenesis of the troctolitic zone of the Bald Eagle Intrusion. To achieve this it will be important to determine the emplacement, venting, crystallization, and compaction history as well as the composition of its parent magma.  This will be accomplished by establishing the lithostratigraphy and chemostratigraphy of its southern bowl area. My research focuses on three Duluth Metals drill holes. The core has been relogged and strategically sampled. Polished thin-sections prepared from the samples will be used for petrographic study and mineral chemical analyses via SEM and electron microprobe.

 

Student: Aubrey Lee
Status: EBT MS candidate
Primary Advisor: Jim Miller

Support
: PRC graduate research assistantship for 2012-13 academic year, PRC research grant ($1000), and UMD block grant ($1000)

Thesis Title: Petrographic and Geochemical Study of the Seine Bay - Bad Vermilion Lake Mafic Layered Intrusion, Numax Resources Inc., Mine Centre Property, Ontario, Canada

Research Description: The objectives of this study are to generate a geologic map of the SBBV based on field observations and previous studies, and to characterize the stratigraphic and stike-parallel variations in the lithologic, petrographic, and geochemical attributes of the SBBV through analyses of hand samples, channel samples, and drill core from three widely spaced traverses across its stratigraphy. The primary research goals include establishing the lithologic and chemical stratigraphy of the intrusion so as to delineate the history of emplacement and crystallization within the magma chamber, and fully characterizing the mineralogic, textural, and chemical attributes of the Fe-Ti oxide layers in order to discern their origin. As a secondary research goal, this study will asses the history of sulfide saturation in the intrusion so as to evaluate the potential for precious metal mineralization.

 

Student: Jon Dyess
Status: 4th Year PhD candidate
Primary Advisor: Vicki Hansen

Support
: PRC graduate research assistantship for Fall 2012 and Spring 2014 semester, PRC research grant ($1000), and UMD block grant ($1000)

Thesis Title: Petrographic and Geochemical Study of the Seine Bay - Bad Vermilion Lake Mafic Layered Intrusion, Numax Resources Inc., Mine Centre Property, Ontario, Canada

Research Description: The Archean (3.85-2.5 Ga) Superior Province, to a first approximation, consists of a series of east-west trending subprovinces of supracrustal rocks (greenstone belts) and granitoid rocks interpreted as a series of microcontinents, remnant arcs, oceanic terranes, and accretionary prisms that accreted to a growing continental block during NW-directed oblique subduction (e.g., Percival et al., 2007, and references therein).  The Vermillion District, southern Superior Province, is a Neoarchean (2.8-2.5 Ga) granite-greenstone terrane dominated by a series of NE-striking subvertical shear zones with ovoid to circular granitic bodies scattered throughout.  Vermillion District shear zones have been interpreted as primarily dextral strike-slip shear zones formed during terrane assembly driven by NW oblique subduction (Hudleston et al., 1988; Percival, 1989; Bauer and Bidwell, 1990; William, 1990; Schultz-Ela and Hudleston, 1991; Borradaile and Spark, 1991; Borradaile et al., 1998).  Others interpret Vermillion District shear zones as zones of dominantly oblique to dip-slip shear possibly formed during greenstone sagduction between rising granitoid diapirs (Erickson, 2008, Goodman, 2008; Karberg, 2009).  Differing interpretations of Vermillion District shear zones invoke different assumptions about displacement direction during non-coaxial shearing.  Displacement direction (flow direction) is genetically tied to foliation and elongation lineation orientation.  Within the Shagawa Lake shear zone of NE Minnesota, displacement direction remains undetermined.  The Shagawa Lake shear zone contains a NE-striking subvertical metamorphic foliation with a variably developed mineral elongation lineation.  Elongation lineation orientation ranges from easterly to westerly steeply plunging with locally preserved shallow plunge.  Adjacent to the Shagawa Lake shear zone is the Snowbank Lake stock, a 30 km2 composite stock dominated by syenite and granodiorite.  Due to the proximity of the Shagawa Lake shear zone to Quetico and/or Wawa subprovince boundary, tectonic fabrics within the Shagawa Lake shear zone have implications for crustal assembly of the southern Superior Province. 

My study represents a multi-scale and multi-pronged approach to the evaluation of tectonic fabrics within the Shagawa Lake shear zone aimed at understanding the deformational history of the Shagawa Lake shear zone, including interactions of the shear zone with the Snowbank Lake stock.  This study includes four phases of analysis: (1) analysis of regional tectonic fabrics through Light Detection and Ranging elevation data; (2) structural analysis of outcrop-scale structures through detailed field mapping; (3) analysis of shear-sense indicators through kinematic and quartz petrofabric analysis; and (4) pressure-temperature analysis.  Data collected during this study will allow for a robust evaluation of displacement within the Shagawa Lake shear zone, and have implications for the formation of Vermillion District shear zones as well as assembly of the southern Superior Province. 


References:
Bauer, R. L and Bidwell, M. E., 1990. Contrasts in the response to dextral transpression across the Quetico-Wawa subprovince boundary in northeastern Minnesota. Canadian Journal of Earth Sciences, 27, 1521-1535.
Borradaile, G., Sarvas, P., Dutka, R., Stewart, R., 1988. Transpression in slates along the margin of an Archean gneiss belt, northern Ontario – magnetic fabrics and petrofabrics. Canadian Journal of Earth Sciences, 25, 1069-1077.
Borradaile, G. and Spark, R., 1991. Deformation of the Archean Quetico-Shebandowan boundary in the Canadian Shield near Kashabowie, northern Ontario. Canadian Journal of Earth Sciences, 28, 116-125.
Erikson, E., 2008. Structural and kienematic analysis of the Shagawa Lake shear zone, Superior Province, northeastern Minnesota. M.S. Thesis, University of Minnesota Duluth, MN.
Goodman, S., 2008. Structural and Kinematic Analysis of the Kawishiwi Shear Zone, Superior Province. M.S. Thesis, University of Minnesota Duluth, MN.
Hudleston, P.J., Schultz-Ela, D., Southwick, D. L., 1988. Transpression in an Archean greenstone belt, northern Minnesota. Canadian Journal of Earth Sciences, vol 25, 1060-1068.
Karberg, S M., 2009. Structural and Kinematic Analysis of the Mud Creek Shear Zone, Northeastern Minnesota. M.S. Thesis, University of Minnesota Duluth, MN.
Percival, J. A., and Williams, H. R., 1989. Late Archean Quetico accretionary complex, Superior Province, Canada. Geology, 17, 23-25.
Percival, J.A., 2007, Geology and metallogeny of the Superior Province, Canada, in Goodfellow,W.D., ed.,Mineral Deposits of Canada:ASynthesis ofMajor Deposit-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No. 5, p. 903-928.
Schultz-Ela, D.D., Hudelston, P.J., 1991. Strain in an Archean greenstone belt of Minnesota. Tectonophysics, 190, 223-268.
Williams, H., 1990. Subprovince accretion tectonics in the south-central Superior Province. Can. J. Earth Sci. 27, 570–581.
2011-2012 Academic Year

Student: Ben Brooker
Status: EBT MS candidate
Primary Advisor: Jim Miller

Support
: PRC graduate research assistantship for the 2011-12 academic year, USGS EDMAP grant ($5340), PRC research grant ($1000), and UMD block grant ($1000)

Thesis Title: Geology and Petrology of a Mesoproterozoic Intrusion in portions of the Brule Lake and Cherokee Lake 7.5’ Quadrangles, Northeastern Minnesota

Research Description: My research focuses on gaining a better understanding of the petrology and magmatic evolution of the 1.1 Ga Midcontinent Rift-related Sawbill Lake Intrusion. The Sawbill Lake Intrusion makes up the westernmost component of the Brule Lake- Hovland gabbro in northeastern Minnesota and has not been mapped in detail. 
       In the summer of 2010, I attended UMD’s Precambrian field camp to fulfill my undergraduate requirement for a six-credit field camp at Illinois State University.  I also chose this camp to become familiar with the geology of the Duluth Complex, which I was considering studying for my MS research at UMD. In the fifth week of the field camp, I participated in a “capstone” mapping project with four other students that focused on mapping part of an as yet unnamed mafic layered intrusion in the Boundary Waters Canoe Area Wilderness (BWCAW).  I found the geology interesting and the experience in the BWCAW left me craving more time in the lakes of northeastern Minnesota. During the capstone project, Jim pitched an idea for a thesis project that would involve integrating our 2010 mapping with capstone mapping conducted in 2007 and 2009 by other Precambrian field camp students.    Collectively, these three, week-long capstone mapping projects covered about 11 square miles of the intrusion, however, many areas of the intrusion remain to be investigated.  Therefore, with support from a USGS EDMAP grant, I conducted three weeks of additional mapping in the summer of 2011. The new areas will be integrated with previous mapping to create a 1:24,000 scale bedrock geologic map of the northern half of the intrusion (the southern half is not well exposed).
            The main objective of this project is to document the igneous stratigraphy of the Sawbill Lake mafic layered intrusion by conducting detailed mapping, a petrographic study, and mineral chemical analyses.  The overall goal of this study is to understand the  emplacement and crystallization history of the intrusion.  One of its more interesting aspects, which petrogenetic models must explain, is that it is composed of a well differentiated sequence of lower troctolite cumulates and upper oxide gabbroic cumulates that are separated by a screen of abundant volcanic and sedimentary hornfels inclusion all along its 15 kilometer strike length.  Stay tuned.  

Ben1

Student: Matt Chaffee
Status: EBT MS candidate
Primary Advisors: Jim Miller (UMD) and Pete Hollings (Lakehead)

Support:
Graduate research assistantship for the 2011-12 academic year, summer employment,  and all analytical costs fully funded by Magma Metals (Canada) Limited, Thunder Bay, Ontario ($40,800)

Thesis Title: Petrographic and Geochemical Study of the Hybrid Rock Unit Associated with the Current Lake Intrusive Complex, Magma Metals’ Thunder Bay North Property

Research Description: The focus of my research consists of characterizing the mineralogical, textural and geochemical attributes of intensely altered and contaminated intrusive rocks associated with the Current Lake Intrusive Complex (CLIC).  Discovered in 2001, the CLIC is one of several recently discovered ultramafic to mafic intrusions associated with the 1,1 Ga Midcontinent Rift (MCR) that host Ni-Cu-PGE deposits (Heggie, 2005; Ware et al., 2008; Rossell, 2008; Goodgame et al.2010; Goldner, 2011: Foley, 2011).  The CLIC is intruded into Archean granites and high-grade schists of the Quetico subprovince.  Largely unexposed in the Current Lake area about 50 kilometers northeast of Thunder Bay, Ontario, the CLIC was discovered when glacially transported ultramafic boulders, containing disseminated sulfide, were located along the shores of Current Lake.  This eventually lead to the initiation of an ongoing drilling project (MacTavish and Smyk, 2010, Goodgame et al., 2010).  The first drill hole intersected 10.5 meters of disseminated mineralization averaging 1.4 g/t Pt, 1.3 g/t Pd, 0.5% Cu, and 0.3% Ni.
            Over the course of drilling, it was discovered that a heterogeneous intrusive rock unit commonly occurs at the margins of the mineralized ultramafic intrusion.  This unit came to be termed the Hybrid Rock Unit (HRU).  The close spatial relationship between the HRU and the CLIC raises the obvious question as to whether these two intrusions are also petrogenetically related. My research will employ core logging, petrographic studies, mineral chemistry and lithogeochemical analysis, and geochemical modeling in order to characterize the mineralogical, textural, and geochemical attributes of the HRU.  The results of this study will address the question of the HRU’s petrogenetic relationship to the CLIC, as well as to understand the origin of its heterogeneity.

References Cited
Foley, D. J., 2011, Petrology and Cu-Ni-PGE Mineralization of the Bovine Igneous Complex, Baraga County, Northern Michigan. M.S. thesis.  University of Minnesota Duluth, Duluth, MN, 83p.
Goldner, B.D., 2011,  Igneous petrology of the Ni-Cu-PGE mineralized Tamarack intrusion, Aitkin and Carlton Counties, Minnesota.  M.S. thesis.  University of Minnesota Duluth, Duluth, MN, 155p.
Goodgame, V.R., J.R. Johnson, A.D. MacTavish, W.E. Stone, K.P. Watkins and G.C. Wilson, 2010, The Thunder Bay North Deposit: Chonolith-Hosted Pt-Pd-Cu-Ni Mineralization Related to the Midcontinent Rift. 11th International Platinum Symposium, Abstract Volume, Sudbury, Ontario. Ontario Geological Survey, Miscellaneous Release–Data 269.
Heggie, G.J. 2005,  Whole rock geochemistry, mineral chemistry, petrology and Pt, Pd mineralization of the Seagull intrusion, northwestern Ontario.  M.Sc. thesis, Lakehead University, Thunder Bay, ON.
MacTavish, A. and Smyk, M.C., 2010, Thunder Bay North Project, Magma Metals Limited. In Miller, J.D., Smyk, M.C. and Hollings, P.N. (eds.).Cu-Ni-PGE deposits in mafic intrusions of the Lake Superior region: A field trip for the 11th International Platinum Symposium; Ontario Geological Survey, Open File Report 6254, 166p.
Rossell, Dean, 2008,  Geology of the Keeweenawan BIC intrusion:  Institute of Lake Superior Geology.  54th Annual Meeting, Marquette, MI, Proceedings and Abstracts, p. 181-199.
Ware, A., Cherry, J., and Ding, X., 2008,  Geology of the Eagle project: Institute of Lake Superior Geology.  54th Annual Meeting, Marquette, MI, Proceedings and Abstracts, p. 87-111.
Matt
Student: Christopher Goscinak
Status: Completed MS degree, July 2013
Primary Advisor: Vicki Hansen

Support:
PRC graduate research assistantship for the 2012 spring semester

Thesis title:
Quartz Fabric Analysis and Interpretation of Archean Shear Zones: Vermilion District, NE Minnesota

Research Description:
 Two suites of end-member hypotheses have been proposed to explain the formation of granite-greenstone terrains which make up large tracts of Archean (3.8-2.5 Ga) crust. 1) Volcanic arc-accretion likens Archean tectonic processes to modern day subduction and arc-accretion systems dominated by horizontal displacements (e.g., Percival and Williams 1989; Card, 1990; Cawood, 2006). 2) Sagduction-diapirism likens Archean tectonic processes to a gravity inversion of less dense felsic plutonic material diapirically rising with respect to the sinking (sagduction) of more dense mafic volcanic material with dominantly vertical displacements (e.g., McGregor, 1951; Anhaeusser et al., 1969; Collins et al., 1998; Bedard et. al, 2003; Van Karendonk et al., 2004; Chardon et al., 2008). Structural fabrics within the Vermilion district of northeastern Minnesota have lead to studies advocating both hypotheses. Studies concluding dextral transpression, supportive of volcanic arc-accretion, interpret dextral shearing perpendicular to the lineation due to oblique convergence (Hudleston et al., 1988; Schultz-Ela and Hudleston, 1991) Other studies, interpreting shearing parallel to the lineation more supportive of the sagduction-diapirism hypothesis (Goodman, 2008; Karberg, 2009; Johnson, 2009; Erikson, 2010). Although examining similar structural data, these studies differ on their interpretations of the motion plane and shearing direction relative to the lineation. Shear sense interpretations must be conducted on the plane of highest asymmetry, the motion plane. Within the Vermilion district, the motion plane can be ambiguous due to the small grain-size of deformed mineral grains.
           To gain insight on how the L-S tectonites formed my research employs fieldwork, microstructure kinematic analysis, and quartz crystallographic fabrics analysis. Fieldwork consists of mapping and determining the extent of a small-unstudied shear zone near the town of Pleya, MN. Microstructure work on will yield a kinematic interpretation of the shear zone. Quartz crystallographic fabrics results in crystallographic preferred orientation (CPO) diagrams and will be analyzed on samples from the Kawishiwi Shear Zone in addition to the Pleya Shear Zone. This kind of structural analysis has yet to be applied to this area and will prove useful, for it confronts first-order issues such as ductile flow direction and orientation of the vorticity vector and motion plane. This will document if flow is parallel, or perpendicular, or at some angle to lineation.

References Cited:

Anhaeusser, C.R., Mason, R., Viljoen, M.J., Viljoen, R.P., 1969. A reappraisal of some aspects of Precambrian shield geology. Geological Society of America Bulletin vol. 80, 2175-2200.
Card, K.D., 1990. A review of the Superior Province of the Canadian Shield, a product of Archean accretion. Precambrian Research, vol 48, 99-156.
Cawood, P.A., Kroner, A., Pisarevsky, S., 2006. Precambrian Plate tectonics: criteria and evidence. GSA Today, vol. 16, 4-11.
Collins, W.J., Van Kranendonk, M.J., Teyssier, C., 1998. Partial convective overturn of Archaean crust in the east Pilbara craton, Western Australia: driving mechanisms and tectonic implications. Journal of Structural Geology vol. 20, 1405-1424. Erikson, E., 2010. Structural and kienematic analysis of the Shagawa Lake shear zone, Superior Province, northen Minnesota: implications for the role of vertical versus horizontal tectonics in the Archean. Canadian Journal of Earth Sciences, vol. 47, 1463-1479.
Goodman, S., 2008. Structural and Kinematic Analysis of the Kawishiwi Shear Zone, Superior Province. M.S. Thesis, University of Minnesota Duluth, MN.
Hudleston, P.J., Schultz-Ela, D., Southwick, D. L., 1988. Transpression in an Archean greenstone belt, northern Minnesota. Canadian Journal of Earth Sciences, vol 25, 1060-1068.
Johnson, T., 2009. Structural, Kinematic and Hydrothermal Fluid Investigation of the Gold-Bearing Murray Shear Zone, Northeastern Minnesota. M.S. Thesis, University of Minnesota Duluth, MN.
Karberg, S M., 2009. Structural and Kinematic Analysis of the Mud Creek Shear Zone, Northeastern Minnesota. M.S. Thesis, University of Minnesota Duluth
Macgregor, A.M., 1951. Some milestones in the Precambrian of Southern Rhodesia. Transactions of the Geological Society of South Africa. 54, 27-71.
Percival, J.A., and Williams, H.R. 1989. Late Archean Quetico accretionary complex, Superior province, Canada. Geology, vol. 17 (1). 23–25.
Schultz-Ela, D.D., Hudleston, P.J., 1991. Strain in an Archean greenstone belt of Minnesota. Tectonophysics, vol. 190, 233-268. 
Van Kranendonk, M.J., Collins, W.J., Hickman, A., Pawley, M., 2004. Critical tests of vertical vs. horizontal tectonic models for the Archaean East Pilbara Granite-Greenstone Terrane, Pilbara Craton, Western Australia. Precambrian Research vol. 131, 173-211.
 
2010-2011 Academic Year

Student: Dan Foley
Status: Completed MS degree, July 2011
Primary Advisor: Jim Miller

Support: PRC graduate research assistantship for 2011 spring semester

Thesis title: Petrology and Cu-Ni-PGE Mineralization of the Bovine Igneous Complex, Baraga County, Northern Michigan

Research Description: My research focuses on gaining a better understanding of the petrology and magmatic evolution of the Midcontinent Rift-related Bovine Igneous Complex.  First discovered in the early nineties in northern Michigan by Rio Tinto, this intrusion has since been extensively drilled in hopes of discovering significant nickel, copper, and PGE reserves (Rossell 2008).  Although only minor mineralization has been observed, a handful of well mineralized early ultramafic rift related intrusions similar to BIC have been discovered in Northern Michigan, Northern Minnesota, and Canada and thus have become increasingly popular exploration targets (Hollings et al. 2007).  The recent successful discovery of several similar mineralized intrusions raises the question as to what differences led to the formation of the poorly mineralized BIC as compared to the better-mineralized intrusions located throughout the rift?  The principal objective of my research is to characterize the igneous stratigraphy, cumulate phase layering, sulfide mineralization, cryptic mineral variation, and bulk geochemical variations of the Bovine Igneous Complex.  Consisting of core logging, field mapping, petrographic studies, and chemical analysis, the result of the research may be a better understanding of what processes are important to the evolution of a poorly versus strongly mineralized intrusion.

References

Hollings, P., Hart, T., Richardson, A., MacDonald, C., A., 2007. Geochemistry of the Mesproterozoic intrusive rocks of the Nipigon Embayment, northwestern Ontario: evaluating the earliest phases of rift development. Canadian Journal of Earth Science, 44, pp. 1087-1110.  
Rossell, D., 2008. Geology of the Keweenawan BIC Intrusion. 54th Annual Institute on Lake Superior Geology, Field Trip Guidebook, v.54, pp. 181-193.



Dan at BIC

2008-2009 Academic Year

Student: Tom Johnson
Status: Completed MS degree July, 2009
Primary Advisors: Vicki Hansen, George Hudak

PRC Support: PRC graduate research assistantship for the 2008-09 academic year

Thesis title: Structural, Kinematic, and Hydrothermal Fluid Investigation of the Murray Shear Zone, northeastern Minnesota with Implications for Gold Mineralization

Research Description: Last summer, I conducted research in the Murray Shear Zone of northeastern Minnesota to investigate its architecture and kinematic history with respect to fluid migration as a catalyst for gold mineralization.  My research involved transect mapping through the Murray Shear Zone, which originates near Tower, MN and continues eastward through Eagle’s Nest Lake.  In the middle to late 1980s, Newmont Mining Corporation discovered subeconomic gold mineralization (12.5 ppm) along the northern margin of the Murray Shear Zone.  Exploratory drill holes intersected anomalous gold in the area but it was believed that economic mining was not feasible (Peterson and Patelke, 2003).  Models of Archean gold deposits have since enabled a deeper understanding with which to base exploration in Archean shear zones.  Sibson (1992) noted that in mesothermal environments (~ 10 km deep), within the brittle/ductile transition at the base of the lithospheric seismogenic regime, a process of intermittent high-pressure hydrothermal fluid release known as fault-pressure-activated valves is responsible for fluid movement up-dip of high-angle structures, mineralization, and hydrothermal self-sealing.  These sub-vertical structures may be present within the Murray Shear Zone as preliminary field data indicate dominant dip-slip features.  The objective of my study is to determine if indeed the Murray Shear Zone is an eroded and exposed mesothermal gold system.  Methods for a thorough investigation include field mapping, drill core logging, thin section study, and whole rock geochemistry.  This research will help to better understand the architecture of the Murray Shear Zone with implications for an economic gold deposit.

References

Peterson, D. M., Patelke, R. L., 2003.  National underground science and engineering laboratory (NUSEL): geological site investigation for the Soudan Mine, northeastern Minnesota.  Economic Geology Group, National Resources Research Institute, University of Minnesota Duluth: Technical Report NRRI/TR-2003/29.
Sibson, R. H., 1992.  Earthquake faulting, induced fluid flow, and fault-hosted gold-quartz mineralization.  In:  Bartholomew, M. J., Hyndman, D. W., Mason, R., Mogk, D. W., (Eds.), Basement Tectonics 8:  Characterization and Comparison of Ancient and Mesozoic Continental Margins—Proceedings of the 8th International Conference on Basement Tectonics (Butte, Montana, 1988) Kluwer Academic Publishers, Dordecht, The Netherlands, pp. 603-614.


Tom Johnson

Tom and Dean

 

2007-2008 Academic Year

Student: Chris White
Status: Completed MS degree June, 2010
Primary Advisor: Jim Miller
Co-advisors: John Goodge, Dean Peterson

PRC Support: 1/2-time graduate research assistantship for the 2007-08 academic year

Progress (9/08): Chris took a full time job in May, 2008 as a geologist with Duluth Metals Ltd. in Ely, MN. He is well into the writing phase of his dissertation and expects to defend his thesis some time in early 2009.

Thesis title: The Magmatic Evolution and Cu-Ni-PGE Mineralization of the Northern South Kawishiwi Intrusion, Duluth Complex, Northeastern Minnesota

Research Description: My thesis work focuses on understanding the igneous petrology and sulfide mineralization of a portion of the 1.1 Ga South Kawishiwi intrusion (SKI), which occurs along the northwestern margin of the Duluth Complex in northeastern Minnesota, Previous studies of the SKI (Severson, 1994) show it to have formed by multiple injections of tholeiitic magma to produce a complex igneous stratigraphy.  Economic grades of Cu-Ni-PGE enriched sulfide occur along the <100m-thick basal zone of the 2+km-thick intrusion and several deposit areas are presently being evaluated for development by various mineral exploration companies.  My work will focus on the Maturi and Nokomis deposits, which occur in northern part of the SKI and are under lease by Duluth Metals, Inc..  Two general styles of mineralization are noted in these deposits: a low-grade, large volume type called open-style and a higher-grade, lower-volume type called confined style (Peterson, 2001).  A major objective of my thesis is to better characterize these contrasting mineralization styles and to test a model proposed by Peterson (2001) that explains the two styles as reflecting different hydrodynamic conditions of sulfide-bearing magma flow under and around a large inclusion block of older gabbroic anorthosite.  My methods of investigation will involve field mapping, drill core logging, petrographic observations, microprobe analysis, and whole rock geochemistry.  This research will result in a more detailed characterization of the igneous stratigraphy and sulfide mineralization and which will in turn lead to a better understanding of the magmatic and metallogenic evolution of the South Kawishiwi intrusion.

References
Peterson, D.M., 2001, Development of a conceptual model of Cu-Ni-PGE mineralization in a portion of the South Kawishiwi intrusion, Duluth Complex, Minnesota: Society of Economic Geologists, Second Annual PGE Workshop, Sudbury, Ontario.
Severson, M.J., 1994, Igneous stratigraphy of the South Kawishiwi Intrusion, Duluth Complex, northeastern Minnesota: NRRI/TR-93/34, 210 p.

Chris and Benedek at Maturi

 

Chris at Omaday Lake

Research Grants

2012Grantees

Student

School

Amount

Purpose

ResearchTopic

Aubrey Lee University of Minnesota Duluth $1000 Thin Sections and Mineral Chemical Analyses for MS thesis Petrographic and Geochemical Study of the Seine Bay - Bad Vermilion Lake Mafic Layered Intrusion, Numax Resources Inc., Mine Centre Property, Ontario, Canada
Adam Leu University of Minnesota Duluth $1000 Thin Sections and Mineral Chemical Analyses for MS thesis Geology and Petrology of the Wilder Lake Intrusion, Duluth Complex, NE Minnesota
Craig Caton University of Minnesota Duluth $1000 Thin Sections and Mineral Chemical Analyses for MS thesis Petrogenesis and Metallogenesis of the Southern Troctolite Zone of the Bald Eagle IntrusionDuluth Complex, Northeastern MN

2011 Grantees

Student

School

Amount

Purpose

ResearchTopic

Ernest Thalhammer U of Wisc. Milwaukee $1000 Field Expenses & Thin Sections for MS thesis Analyzing ductile shear zone network geometries in the Grassy Portage Sill, Rainy Lake region, northwestern Ontario, Canada
Jon Dyess University of Minnesota Duluth $1000 Field Expenses & Thin Sections for PhD thesis Emplacement of Late Archean granitoid bodies in the Superior Province, northeastern Minnesota
Chris Goscinak University of Minnesota Duluth $1000 Field Expenses & Thin Sections for MS thesis Crystallographic preferred orientations and structural and kinematic analysis of multiple Archean shear zones, Superior Province Northeastern Minnesota
Amy Radakovich University of Minnesota Duluth $1000 Mineral Chemical Analyses for MS thesis Metamorphic petrology of glacial clasts from the Byrd Glacier drainage: Implications for the crustal history of East Antarctica
Ben Brooker University of Minnesota Duluth $1400 Mineral Chemical Analyses for MS thesis Geology and petrology of the Sawbill Lake intrusion, Brule Lake and Cherokee Lake 7.5’ Quadrangles, Northeastern Minnesota

2010 Grantees

Student

School

Amount

Purpose

ResearchTopic

Michael DeVasto U of Wisc. Milwaukee $1000 Thin Sections for MS thesis Quantifying the relationship between geochemical and microtextural changes across small-scale granitic shear zones near Mountain, WI
Robert Mahon Idaho St University $1000 Thin Sections for MS thesis Geologic Map of the Saddle Peak Hills 7.5’ Quadrangle and Sedimentology and Age Constraints of the Meso-Neoproterozoic Pahrump Group, Death Valley, California
Nicholas Swanson-Hysell Princeton University $1000 Field Expenses A stratigraphic approach to determining the paleointensity of the late Mesoproterozoic geomagnetic field during a period of rapid latitudinal plate motion, Mamainse Pt, ON

2009 Grantees

Student

School

Amount

Purpose

ResearchTopic

Melissa Hage Univ. of Tennessee-Knoxville $1000 Thin sections for PhD thesis

The Effects of Metamorphism on the Petrology and Geochemistry of ~1.9 Ga Gunflint Iron Formation, Minnesota and Ontario

Evan Finnes University of Minnesota $1000 Thin sections and field expenses for MS thesis

AMS Study of Duluth Complex Igneous Intrusions

 

Shelby Frost UMD $1000 Thin sections for MS thesis Effects of Contact Metamorphism by the Duluth Complex on Proterozoic Footwall Rocks in Northeastern Minnesota

Dan Costello UMD $134 Thin sections for MS thesis

Geology and Petrology of the Tuscarora Intrusion of the
Duluth Complex, Gillis Lake 7.5’ Quadrangle, Northeastern Minnesota

Eric Stifter UMD $457 Whole rock analyses for undergraduate research

Cyclical Phase Layering in the Duluth Complex at Duluth – Evidence for Periodic Magma Venting from a Shallow Staging Chamber

Ryan Dayton UMD $111 Whole rock analyses for MS thesis Quantifying Assimilation vs. Fractional Crystallization using Sm-Nd, Lu-Hf and Pb isotope systems: The Geochemical Evolution of the Sonju Lake Intrusion, Finland, MN

2008 Grantees

Student

School

Amount

Purpose

ResearchTopic

Chris White

UMD

1400

Microprobe analyses for MS thesis

Magmatic evolution and Cu-Ni-PGE mineralization of the northern South Kawishiwi Intrusion, Duluth Complex, northeastern Minnesota

Terra Anderson

U of Wisc.-
Milwaukee

1000

Thin sections for MS thesis

Linking the development of quartz fabrics and quantified strains during transpressional deformation

Emerald Erickson

UMD

495

Thin sections for MS thesis

Structural and kinematic analysis of the Shagawa Lake shear zone, Superior Province, northeastern Minnesota: Implications for Archean (~2.75 Ga) crustal evolution

Susan Karberg

UMD

506

Thin sections for MS thesis

Structural and kinematic analysis of the Mud Creek shear zone, Superior Province, northeastern Minnesota: Implications for Archean (~2.7 Ga) tectonics

Tom Johnson

UMD

1000

Field expenses for MS thesis

Structural, kinematic, and hydrothermal fluid investigation of the Murray Shear Zone, northeastern Minnesota with implications for gold mineralization



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