Browsing by Subject "Babbitt Cu-Ni deposit"

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    The Babbitt Copper-Nickel Deposit: Part A: Digital Drill Hole Data Files for the Babbitt and Serpentine Copper-Nickel Deposits
    (University of Minnesota Duluth, 1994-09) Patelke, Richard L
    The main objective of this investigation is to assist Arimetco International, Inc. in their evaluation of establishing a non-ferrous mine in northeastern Minnesota. This portion of the report presents data compilation work done on the Babbitt and Serpentine Cu-Ni deposits by the NRRI. The purpose was to put all available copper-nickel-sulfur assays, precious metal assays, RQD (Rock Quality Designation) information, and down hole drill hole survey data into a uniform digital format.
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    The Babbitt Copper-Nickel Deposit: Part B: Structural Datums
    (University of Minnesota Duluth, 1994-09) Severson, Mark J; Patelke, Richard L; Hauck, Steven A; Zanko, Lawrence M
    This portion of the investigation concentrated on determining specific structural and stratigraphic datums within the Babbitt Cu-Ni deposit of the Partridge River Intrusion, Duluth Complex, northeastern Minnesota. Structural datums and footwall lithologies were obtained by relogging the footwall portions of all surface drill holes (391) within the confines of the deposit. Specific lithologies recorded during relogging included depth to: 1) basal contact of the Duluth Complex with the footwall rocks; 2) distinctive units within the footwall Virginia Formation; and 3) top of the underlying Biwabik Iron-formation and the specific iron-formation submembers intersected in drill hole. In addition, 100 surface drill holes were relogged in detail and compared with 166 previously relogged drill holes. The top of Unit I, the main sulfide-bearing igneous unit of the Babbitt deposit, was determined for all 266 drill holes that were relogged. The top of the first significant sulfide-bearing zone (not always the top of Unit I) was also determined for the relogged drill holes. All these datum points are used to generate several contoured surface maps to gain a better understanding of the main structural features present within the Babbitt deposit. The contoured surface for the top of the Biwabik Iron-formation is an excellent means of displaying the major structural features, i.e., the Local Boy Anticline, Bathtub Syncline, and Grano Fault. These same features are evident in the contoured surface of the basal contact and indicate that pre-existing structures in the footwall were important to how the basal portion of the Duluth Complex was emplaced. Datum points within the upper portion of the Duluth Complex also suggest that these structures were reactivated throughout the emplacement history of the Duluth Complex (see discussion in Part C). Some of the structures were also important controls of Cu-Ni mineralization. A contoured surface of the bedrock ledge is also presented for the Babbitt deposit. Several structural features are outlined by the bedrock ledge. A crude subsurface geologic map is also portrayed for the bedrock ledge. In addition, an isopach map of glacial overburden thickness is included in this report.
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    The Babbitt Copper-Nickel Deposit: Part C: Igneous Geology, Footwall Lithologies, and Cross-Sections
    (University of Minnesota Duluth, 1996-03) Severson, Mark J; Patelke, Richard L; Hauck, Steven A; Zanko, Lawrence M
    Twenty-five cross-sections are presented that display the detailed igneous geology for several areas of the Babbitt Cu-Ni deposit. Shown in the cross-sections are the stratigraphic relationships of at least seven major igneous units - Units I through VII of the Partridge River Troctolite Series (PRTS). However, not all seven units are equally present throughout the deposit due to "pinch-out" relationships and lateral gradational rock type changes. In addition to these seven units, three new units are briefly discussed and include the: 1) Bathtub Layered Series (BTLS) of Hauck (1993); 2) Basal Ultramafic Unit (BU Unit) of Severson (1994); and 3) Upper Layered Series (ULS). Small plug-like bodies of Oxide-bearing Ultramafic Intrusions (OUIs) are also locally present within the Babbitt deposit. They intrude the rocks of the PRTS and are often positioned adjacent to, or within, fault zones. Rock types found within the footwall rocks beneath the Complex at the Babbitt deposit are also described. Metamorphic textural variations are described for select units within the Virginia Formation (RXTAL, DISRUPTED, and BDD PO units). These textural variations indicate that the effects of structural deformation, recrystallization, and partial melting are more pronounced than previously thought. The exact origin of the textures is unknown, but is believed to be associated with early stages of Duluth Complex emplacement. Also present within the basal portion of the Virginia Formation are early intrusive rocks that predate emplacement of the Partridge River intrusion (PRI). These early intrusive rocks are referred to as the Virg Sill and "Massive Gray" Unit ("MG" Unit); both are interrelated and are submembers of a single composite sill. At least three major structural features are present in the footwall rocks and include the: Local Boy Anticline, Bathtub Syncline, and Grano Fault (for a more detailed discussion see Part B - Severson et al., 1994). During intrusion of the Partridge River intrusion, specifically during emplacement of the lowest unit (Unit I), the Local Boy Anticline and Bathtub Syncline were important factors controlling how the base of the Complex was formed (see Part B). In addition, these same structures also appear to have been repeatedly reactivated during continued emplacement of the Complex and affected the distribution of specific units within overlying Unit III and the BTLS. Also, the distribution of the "MG" and Virg Sill units are affected by these same two structures. These relationships suggest that reactivation of the structures created "void spaces" into which specific PRTS units were emplaced. The exact details and of this complicated emplacement history have yet to be unraveled.