Precambrian Research Center

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.

Student: Adam Leu
Status: 1st Year MS candidate
Primary Advisor: Jim Miller

Support: USGS EDMAP Grant ($14,670), PRC graduate research assistantship for Fall 2012 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: 2nd Year MS candidate
Primary Advisor: Penny Morton

Support: PRC graduate research assistantship for 2012-13 academic year, 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: 2nd Year 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: 3rd Year PhD candidate
Primary Advisor: Vicki Hansen

Support: PRC graduate research assistantship for Fall 2012 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

Student: Ben Brooker
Status: 2nd Year 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.  

Student: Matt Chaffee
Status: 2nd year 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.

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

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

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.

2010 Grantees

2009 Grantees

2008 Grantees

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